EC21 Hardware Design
LTE Standard Module Series
Rev. EC21_Hardware_Design_V1.7
Date: 2019-08-19
Status: Released
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LTE Standard Module Series
EC21 Hardware Design
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EC21_Hardware_Design 1 / 120
LTE Standard Module Series
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About the Document
History
Revision Date Author Description
1.0 2016-04-15 Yeoman CHEN Initial
Yeoman CHEN/
1.1 2016-09-22
1.2 2016-11-04
Frank WANG/
Lyndon LIU
Lyndon LIU/
Michael ZHANG
1. Updated frequency bands in Table 1.
2. Updated transmitting power, supported maximum
baud rate of main UART, supported internet
protocols, supported USB drivers of USB interface,
and temperature range in Table 2.
3. Updated timing of turning on module in Figure 12.
4. Updated timing of turning off module in Figure 13.
5. Updated timing of resetting module in Figure 16.
6. Updated main UART supports baud rate in Chapter
3.11.
7. Added notes for ADC interface in Chapter 3.13.
8. Updated GNSS Performance in Table 21.
9. Updated operating frequencies of module in Table
23.
10. Added current consumption in Chapter 6.4.
11. Updated RF output power in Chapter 6.5.
12. Added RF receiving sensitivity in Chapter 6.6.
1. Added SGMII and WLAN interfaces in Table 2.
2. Updated function diagram in Figure 1.
3. Updated pin assignment (Top View) in Figure 2.
4. Added description of SGMII and WLAN interfaces in
Table 4.
5. Added SGMII interface in Chapter 3.17.
6. Added WLAN interface in Chapter 3.18.
7. Added USB_BOOT interface in Chapter 3.19.
8. Added reference design of RF layout in Chapter
5.1.4.
9. Added current consumption of EC21-V in Chapter
EC21_Hardware_Design 2 / 120
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6.4
10. Added note about SIMO in Chapter 6.6.
1. Updated frequency bands in Table 1.
2. Updated function diagram in Figure 1.
3. Updated pin assignment (top view) in Figure 2.
4. Added BT interface in Chapter 3.18.2.
5. Updated reference circuit of wireless connectivity
1.3 2017-01-24
Lyndon LIU/
Rex WANG
interfaces with FC20 module in Figure 29.
6. Updated GNSS performance in Table 24.
7. Updated module operating frequencies in Table 26.
8. Added EC21-AUV current consumption in Table 38.
9. Updated EC21-A conducted RF receiving sensitivity
of in Table 42.
10. Added EC21-J conducted RF receiving sensitivity in
Table 48.
1.4 2017-03-01 Geely YANG Deleted the LTE band TDD B41 of EC21-CT
1. Updated functional diagram in Figure 1.
2. Updated frequency bands in Table 1.
3. Updated UMTS and GSM features in Table 2.
4. Updated description of pin 40/136/137/138.
5. Updated PWRKEY pulled down time to 500ms in
chapter 3.7.1 and reference circuit in Figure 10.
6. Updated reference circuit of (U)SIM interface in
Figure 17&18.
7. Updated reference circuit of USB interface in Figure
19.
8. Updated PCM mode in Chapter 3.12.
9. Updated USB_BOOT reference circuit in Chapter
Annice ZHANG/
1.5 2018-03-05
Lyndon LIU/
Frank WANG
3.20.
10. Added SD card interface in Chapter 3.13.
11. Updated module operating frequencies in Table 26.
12. Updated EC21 series modules current consumption
in Chapter 6.5.
13. Updated EC21 series modules conducted RF
receiving sensitivity in Chapter 6.6.
14. Added thermal consideration description in Chapter
6.8.
15. Updated dimension tolerance information in
Chapter 7.
16. Added storage temperature range in Table 2 and
Chapter 6.3.
17. Updated RF output power in Table 42.
18. Updated antenna requirements in Table 29.
EC21_Hardware_Design 3 / 120
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19. Updated GPRS multi-slot classes in Table 55.
20. Updated storage information in Chapter 8.1
1. Added new variants EC21-EU and related
information.
2. Updated star structure of the power supply in Figure
8.
3. Updated power-on scenario of module in Figure 12.
4. Updated reference circuit with translator chip in
Figure 20.
5. Added timing sequence for entering into emergency
download mode of USB_BOOT interface in Figure
32.
6. Updated GNSS frequency in Table 29.
7. Updated antenna requirements in Table 30.
8. Added EC21-EU current consumption in Table 41.
9. Added EC21-EC current consumption in Table 42.
Woody WU/
1.6 2019-04-30
Nathan LIU/
Frank WANG
10. Updated EC21-E conducted RF receiving sensitivity
in Table 44.
11. Updated EC21-A conducted RF receiving sensitivity
in Table 45.
12. Updated EC21-V conducted RF receiving sensitivity
in Table 46.
13. Updated EC21-AUT conducted RF receiving
sensitivity in Table 47.
14. Updated EC21-AU conducted RF receiving
sensitivity in Table 51.
15. Added EC21-EU conducted RF receiving sensitivity
in Table 52.
16. Added EC21-EC conducted RF receiving sensitivity
in Table 53.
17. Updated recommended stencil thickness as
0.18mm~0.20mm and reflow soldering thermal
profile in Chapter 8.2.
1. Added ThreadX variant EC21-AUX and updated
related information in Table 1 and Chapter 2.1.
2. Deleted the information of GNSS supported on
EC21-EC in Table 1
1.7 2019-08-19
Ward WANG/
Owen WEI
3. Updated supported protocols and USB serial driver
in Table 2.
4. Updated functional diagram in Figure 1.
5. Updated notes in Chapter 3.7.1.
6. Updated EC21-E current consumption (GSM voice
call) in Table 34.
7. Updated EC21-EU current consumption in Table 41.
EC21_Hardware_Design 4 / 120
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8. Updated EC21-EC current consumption in Table 42.
9. Added EC21-AUX current consumption in Table 43.
10. Updated EC21-EU conducted RF receiving
sensitivity in Table 53.
11. Added EC21-AUX conducted RF receiving
sensitivity in Table 55.
12. Updated module bottom dimensions (bottom view)
in Figure 45.
13. Added tape and reel directions in Figure 51.
EC21_Hardware_Design 5 / 120
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Contents
About the Document ................................................................................................................................ 2
Contents .................................................................................................................................................... 6
Table Index ............................................................................................................................................... 9
Figure Index ............................................................................................................................................ 11
1 Introduction ..................................................................................................................................... 13
1.1. Safety Information ................................................................................................................. 14
2 Product Concept ............................................................................................................................. 18
2.1. General Description .............................................................................................................. 18
2.2. Key Features ......................................................................................................................... 19
2.3. Functional Diagram ............................................................................................................... 22
2.4. Evaluation Board ................................................................................................................... 23
3 Application Interfaces ..................................................................................................................... 24
3.1. General Description .............................................................................................................. 24
3.2. Pin Assignment ..................................................................................................................... 25
3.3. Pin Description ...................................................................................................................... 26
3.4. Operating Modes .................................................................................................................. 38
3.5. Power Saving ........................................................................................................................ 38
3.5.1.
Sleep Mode.................................................................................................................. 38
3.5.1.1. UART Application ............................................................................................... 39
3.5.1.2. USB Application with USB Remote Wakeup Function ....................................... 39
3.5.1.3. USB Application with USB Suspend/Resume and RI Function .......................... 40
3.5.1.4. USB Application without USB Suspend Function ............................................... 41
3.5.2. Airplane Mode .............................................................................................................. 41
3.6. Power Supply ........................................................................................................................ 42
3.6.1. Power Supply Pins ....................................................................................................... 42
3.6.2. Decrease Voltage Drop ................................................................................................ 43
3.6.3. Reference Design for Power Supply ............................................................................ 44
3.6.4. Monitor the Power Supply ............................................................................................ 44
3.7. Power-on/off Scenarios ......................................................................................................... 45
3.7.1. Turn on Module Using the PWRKEY ........................................................................... 45
3.7.2. Turn off Module ............................................................................................................ 47
3.7.2.1. Turn off Module Using the PWRKEY Pin ........................................................... 47
3.7.2.2. Turn off Module Using AT Command ................................................................. 47
3.8. Reset Module ........................................................................................................................ 48
3.9. (U)SIM Interface .................................................................................................................... 49
3.10. USB Interface ........................................................................................................................ 51
3.11. UART Interfaces .................................................................................................................... 53
3.12. PCM and I2C Interfaces ........................................................................................................ 55
3.13. SD Card Interface ................................................................................................................. 58
3.14. Wireless Connectivity Interfaces ........................................................................................... 59
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3.14.1. WLAN Interface ........................................................................................................... 62
3.14.2. BT Interface* ................................................................................................................ 62
3.15. ADC Interfaces ...................................................................................................................... 62
3.16. SGMII Interface ..................................................................................................................... 63
3.17. Network Status Indication ...................................................................................................... 66
3.18. STATUS ................................................................................................................................ 67
3.19. Behaviors of RI ..................................................................................................................... 68
3.20. USB_BOOT Interface ............................................................................................................ 69
4 GNSS Receiver ................................................................................................................................ 71
4.1. General Description .............................................................................................................. 71
4.2. GNSS Performance .............................................................................................................. 71
4.3. Layout Guidelines ................................................................................................................. 72
5 Antenna Interfaces .......................................................................................................................... 73
5.1. Main/Rx-diversity Antenna Interfaces.................................................................................... 73
5.1.1. Pin Definition ................................................................................................................ 73
5.1.2. Operating Frequency ................................................................................................... 73
5.1.3. Reference Design of RF Antenna Interface ................................................................. 74
5.1.4.
Reference Design of RF Layout ................................................................................... 75
5.2. GNSS Antenna Interface ....................................................................................................... 77
5.3. Antenna Installation ............................................................................................................... 79
5.3.1. Antenna Requirement .................................................................................................. 79
5.3.2. Recommended RF Connector for Antenna Installation ................................................ 80
6 Electrical, Reliability and Radio Characteristics .......................................................................... 82
6.1. Absolute Maximum Ratings .................................................................................................. 82
6.2. Power Supply Ratings ........................................................................................................... 83
6.3. Operation and Storage Temperatures ................................................................................... 83
6.4. Current Consumption ............................................................................................................ 84
6.5. RF Output Power .................................................................................................................. 98
6.6. RF Receiving Sensitivity ....................................................................................................... 99
6.7. Electrostatic Discharge ....................................................................................................... 105
6.8. Thermal Consideration ........................................................................................................ 105
7 Mechanical Dimensions................................................................................................................ 108
7.1. Mechanical Dimensions of the Module................................................................................ 108
7.2. Recommended Footprint
...................................................................................................... 110
7.3. Design Effect Drawings of the Module ................................................................................. 111
8 Storage, Manufacturing and Packaging ...................................................................................... 112
8.1. Storage................................................................................................................................. 11 2
8.2. Manufacturing and Soldering ............................................................................................... 113
8.3. Packaging ............................................................................................................................ 114
9 Appendix A References ................................................................................................................ 116
10 Appendix B GPRS Coding Schemes ........................................................................................... 120
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11 Appendix C GPRS Multi-slot Classes .......................................................................................... 121
12 Appendix D EDGE Modulation and Coding Schemes ................................................................ 123
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Table Index
TABLE 1: FREQUENCY BANDS OF EC21 SERIES MODULE ........................................................................ 18
TABLE 2: KEY FEATURES OF EC21 MODULE ............................................................................................... 19
TABLE 3: I/O PARAMETERS DEFINITION ....................................................................................................... 26
TABLE 4: PIN DESCRIPTION ........................................................................................................................... 26
TABLE 5: OVERVIEW OF OPERATING MODES ............................................................................................. 38
TABLE 6: VBAT AND GND PINS ....................................................................................................................... 42
TABLE 7: PIN DEFINITION OF PWRKEY ........................................................................................................ 45
TABLE 8: PIN DEFINITION OF RESET_N ....................................................................................................... 48
TABLE 9: PIN DEFINITION OF (U)SIM INTERFACE ....................................................................................... 50
TABLE 10: PIN DESCRIPTION OF USB INTERFACE ..................................................................................... 52
TABLE 11: PIN DEFINITION OF MAIN UART INTERFACE ............................................................................. 53
TABLE 12: PIN DEFINITION OF DEBUG UART INTERFACE ......................................................................... 54
TABLE 13: LOGIC LEVELS OF DIGITAL I/O .................................................................................................... 54
TABLE 14: PIN DEFINITION OF PCM AND I2C INTERFACES ....................................................................... 57
TABLE 15: PIN DEFINITION OF SD CARD INTERFACE ................................................................................ 58
TABLE 16: PIN DEFINITION OF WIRELESS CONNECTIVITY INTERFACES ................................................ 60
TABLE 17: PIN DEFINITION OF ADC INTERFACES ....................................................................................... 63
TABLE 18: CHARACTERISTIC OF ADC .......................................................................................................... 63
TABLE 19: PIN DEFINITION OF SGMII INTERFACE ...................................................................................... 64
TABLE 20: PIN DEFINITION OF NETWORK CONNECTION STATUS/ACTIVITY INDICATOR ...................... 66
TABLE 21: WORKING STATE OF NETWORK CONNECTION STATUS/ACTIVITY INDICATOR ................... 66
TABLE 22: PIN DEFINITION OF STATUS ........................................................................................................ 67
TABLE 23: BEHAVIORS OF RI ......................................................................................................................... 68
TABLE 24: PIN DEFINITION OF USB_BOOT INTERFACE ............................................................................. 69
TABLE 25: GNSS PERFORMANCE ................................................................................................................. 71
TABLE 26: PIN DEFINITION OF RF ANTENNAS ............................................................................................. 73
TABLE 27: MODULE OPERATING FREQUENCIES ........................................................................................ 73
TABLE 28: PIN DEFINITION OF GNSS ANTENNA INTERFACE ..................................................................... 77
TABLE 29: GNSS FREQUENCY ....................................................................................................................... 78
TABLE 30: ANTENNA REQUIREMENTS .......................................................................................................... 79
TABLE 31: ABSOLUTE MAXIMUM RATINGS .................................................................................................. 82
TABLE 32: POWER SUPPLY RATINGS ........................................................................................................... 83
TABLE 33: OPERATION AND STORAGE TEMPERATURES .......................................................................... 83
TABLE 34: EC21-E CURRENT CONSUMPTION ............................................................................................. 84
TABLE 35: EC21-A CURRENT CONSUMPTION ............................................................................................. 86
TABLE 36: EC21-V CURRENT CONSUMPTION ............................................................................................. 87
TABLE 37: EC21-AUT CURRENT CONSUMPTION ........................................................................................ 87
TABLE 38: EC21-AUV CURRENT CONSUMPTION ........................................................................................ 88
TABLE 39: EC21-J CURRENT CONSUMPTION .............................................................................................. 89
TABLE 40: EC21-KL CURRENT CONSUMPTION ........................................................................................... 90
TABLE 41: EC21-EU CURRENT CONSUMPTION ........................................................................................... 91
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TABLE 42: EC21-EC CURRENT CONSUMPTION ........................................................................................... 93
TABLE 43: EC21-AUX CURRENT CONSUMPTION ........................................................................................ 95
TABLE 44: RF OUTPUT POWER ..................................................................................................................... 98
TABLE 45: EC21-E CONDUCTED RF RECEIVING SENSITIVITY .................................................................. 99
TABLE 46: EC21-A CONDUCTED RF RECEIVING SENSITIVITY ................................................................ 100
TABLE 47: EC21-V CONDUCTED RF RECEIVING SENSITIVITY ................................................................ 100
TABLE 48: EC21-AUT CONDUCTED RF RECEIVING SENSITIVITY ........................................................... 100
TABLE 49: EC21-KL CONDUCTED RF RECEIVING SENSITIVITY .............................................................. 101
TABLE 50: EC21-J CONDUCTED RF RECEIVING SENSITIVITY................................................................. 101
TABLE 51: EC21-AUV CONDUCTED RF RECEIVING SENSITIVITY ........................................................... 101
TABLE 52: EC21-AU CONDUCTED RF RECEIVING SENSITIVITY ............................................................. 102
TABLE 53: EC21-EU CONDUCTED RF RECEIVING SENSITIVITY ............................................................. 103
TABLE 54: EC21-EC CONDUCTED RF RECEIVING SENSITIVITY ............................................................. 103
TABLE 55: EC21-AUX CONDUCTED RF RECEIVING SENSITIVITY ........................................................... 104
TABLE 56: ELECTROSTATICS DISCHARGE CHARACTERISTICS (25ºC, 45% RELATIVE HUMIDITY) .... 105
TABLE 57: RECOMMENDED THERMAL PROFILE PARAMETERS .............................................................. 113
TABLE 58: RELATED DOCUMENTS ............................................................................................................... 116
TABLE 59: TERMS AND ABBREVIATIONS ..................................................................................................... 116
TABLE 60: DESCRIPTION OF DIFFERENT CODING SCHEMES ................................................................ 120
TABLE 61: GPRS MULTI-SLOT CLASSES .................................................................................................... 121
TABLE 62: EDGE MODULATION AND CODING SCHEMES ......................................................................... 123
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Figure Index
FIGURE 1: FUNCTIONAL DIAGRAM ............................................................................................................... 23
FIGURE 2: PIN ASSIGNMENT (TOP VIEW) .................................................................................................... 25
FIGURE 3: SLEEP MODE APPLICATION VIA UART ....................................................................................... 39
FIGURE 4: SLEEP MODE APPLICATION WITH USB REMOTE WAKEUP .................................................... 40
FIGURE 5: SLEEP MODE APPLICATION WITH RI ......................................................................................... 40
FIGURE 6: SLEEP MODE APPLICATION WITHOUT SUSPEND FUNCTION ................................................ 41
FIGURE 7: POWER SUPPLY LIMITS DURING BURST TRANSMISSION ...................................................... 43
FIGURE 8: STAR STRUCTURE OF THE POWER SUPPLY ............................................................................ 43
FIGURE 9: REFERENCE CIRCUIT OF POWER SUPPLY .............................................................................. 44
FIGURE 10: TURN ON THE MODULE BY USING DRIVING CIRCUIT ........................................................... 45
FIGURE 11: TURN ON THE MODULE BY USING KEYSTROKE .................................................................... 46
FIGURE 12: TIMING OF TURNING ON MODULE ........................................................................................... 46
FIGURE 13: TIMING OF TURNING OFF MODULE ......................................................................................... 47
FIGURE 14: REFERENCE CIRCUIT OF RESET_N BY USING DRIVING CIRCUIT ...................................... 48
FIGURE 15: REFERENCE CIRCUIT OF RESET_N BY USING BUTTON ...................................................... 49
FIGURE 16: TIMING OF RESETTING MODULE ............................................................................................. 49
FIGURE 17: REFERENCE CIRCUIT OF (U)SIM INTERFACE WITH AN 8-PIN (U)SIM CARD CONNECTOR
................................................................................................................................................................... 50
FIGURE 18: REFERENCE CIRCUIT OF (U)SIM INTERFACE WITH A 6-PIN (U)SIM CARD CONNECTOR . 51
FIGURE 19: REFERENCE CIRCUIT OF USB APPLICATION ......................................................................... 52
FIGURE 20: REFERENCE CIRCUIT WITH TRANSLATOR CHIP ................................................................... 54
FIGURE 21: REFERENCE CIRCUIT WITH TRANSISTOR CIRCUIT .............................................................. 55
FIGURE 22: PRIMARY MODE TIMING ............................................................................................................ 56
FIGURE 23: AUXILIARY MODE TIMING .......................................................................................................... 56
FIGURE 24: REFERENCE CIRCUIT OF PCM APPLICATION WITH AUDIO CODEC .................................... 57
FIGURE 25: REFERENCE CIRCUIT OF SD CARD INTERFACE .................................................................... 58
FIGURE 26: REFERENCE CIRCUIT OF WIRELESS CONNECTIVITY INTERFACES WITH FC20 MODULE
................................................................................................................................................................... 61
FIGURE 27: SIMPLIFIED BLOCK DIAGRAM FOR ETHERNET APPLICATION ............................................. 64
FIGURE 28: REFERENCE CIRCUIT OF SGMII INTERFACE WITH PHY AR8033 APPLICATION ................. 65
FIGURE 29: REFERENCE CIRCUIT OF THE NETWORK INDICATOR .......................................................... 67
FIGURE 30: REFERENCE CIRCUITS OF STATUS ......................................................................................... 68
FIGURE 31: REFERENCE CIRCUIT OF USB_BOOT INTERFACE ................................................................ 69
FIGURE 32: TIMING SEQUENCE FOR ENTERING EMERGENCY DOWNLOAD MODE ............................. 70
FIGURE 33: REFERENCE CIRCUIT OF RF ANTENNA INTERFACE ............................................................. 75
FIGURE 34: MICROSTRIP DESIGN ON A 2-LAYER PCB ............................................................................... 76
FIGURE 35: COPLANAR WAVEGUIDE DESIGN ON A 2-LAYER PCB ........................................................... 76
FIGURE 36: COPLANAR WAVEGUIDE DESIGN ON A 4-LAYER PCB (LAYER 3 AS REFERENCE GROUND)
................................................................................................................................................................... 76
FIGURE 37: COPLANAR WAVEGUIDE DESIGN ON A 4-LAYER PCB (LAYER 4 AS REFERENCE GROUND)
................................................................................................................................................................... 77
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FIGURE 38: REFERENCE CIRCUIT OF GNSS ANTENNA ............................................................................. 78
FIGURE 39: DIMENSIONS OF THE U.FL-R-SMT CONNECTOR (UNIT: MM) ................................................ 80
FIGURE 40: MECHANICALS OF U.FL-LP CONNECTORS ............................................................................. 80
FIGURE 41: SPACE FACTOR OF MATED CONNECTOR (UNIT: MM) ........................................................... 81
FIGURE 42: REFERENCED HEATSINK DESIGN (HEATSINK AT THE TOP OF THE MODULE) ................ 106
FIGURE 43: REFERENCED HEATSINK DESIGN (HEATSINK AT THE BACKSIDE OF CUSTOMERS’ PCB)
................................................................................................................................................................. 106
FIGURE 44: MODULE TOP AND SIDE DIMENSIONS ................................................................................... 108
FIGURE 45: MODULE BOTTOM DIMENSIONS (BOTTOM VIEW) ............................................................... 109
FIGURE 46: RECOMMENDED FOOTPRINT (TOP VIEW) ............................................................................. 110
FIGURE 47: TOP VIEW OF THE MODULE ..................................................................................................... 111
FIGURE 48: BOTTOM VIEW OF THE MODULE ............................................................................................. 111
FIGURE 49: REFLOW SOLDERING THERMAL PROFILE ............................................................................. 113
FIGURE 50: TAPE AND REEL SPECIFICATIONS .......................................................................................... 115
FIGURE 51: TAPE AND REEL DIRECTIONS .................................................................................................. 115
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1 Introduction
This document defines EC21 module and describes its air interface and hardware interfaces which are
connected with customers’ applications.
This document can help customers quickly understand module interface specifications, electrical and
mechanical details, as well as other related information of EC21 module. To facilitate its application in
different fields, relevant reference design is also provided for customers’ reference. Associated with
application note and user guide, customers can use EC21 module to design and set up mobile
applications easily.
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1.1. Safety Information
The following safety precautions must be observed during all phases of operation, such as usage, service
or repair of any cellular terminal or mobile incorporating EC21 module. Manufacturers of the cellular
terminal should send the following safety information to users and operating personnel, and incorporate
these guidelines into all manuals supplied with the product. If not so, Quectel assumes no liability for
customers’ failure to comply with these precautions.
Full attention must be given to driving at all times in order to reduce the risk of an
accident. Using a mobile while driving (even with a handsfree kit) causes
distraction and can lead to an accident. Please comply with laws and regulations
restricting the use of wireless devices while driving.
Switch off the cellular terminal or mobile before boarding an aircraft. The operation
of wireless appliances in an aircraft is forbidden to prevent interference with
communication systems. If the device offers an Airplane Mode, then it should be
enabled prior to boarding an aircraft. Please consult the airline staff for more
restrictions on the use of wireless devices on boarding the aircraft.
Wireless devices may cause interference on sensitive medical equipment, so
please be aware of the restrictions on the use of wireless devices when in
hospitals, clinics or other healthcare facilities.
Cellular terminals or mobiles operating over radio signals and cellular network
cannot be guaranteed to connect in all possible conditions (for example, with
unpaid bills or with an invalid (U)SIM card). When emergent help is needed in such
conditions, please remember using emergency call. In order to make or receive a
call, the cellular terminal or mobile must be switched on in a service area with
adequate cellular signal strength.
The cellular terminal or mobile contains a transmitter and receiver. When it is ON, it
receives and transmits radio frequency signals. RF interference can occur if it is
used close to TV set, radio, computer or other electric equipment.
In locations with potentially explosive atmospheres, obey all posted signs to turn
off wireless devices such as your phone or other cellular terminals. Areas with
potentially explosive atmospheres include fuelling areas, below decks on boats,
fuel or chemical transfer or storage facilities, areas where the air contains
chemicals or particles such as grain, dust or metal powders, etc.
EC21_Hardware_Design 14 / 120
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FCC Certification Requirements.
According to the definition of mobile and fixed device is described in Part 2.1091(b), this device is a
mobile device.
And the following conditions must be met:
1. This Modular Approval is limited to OEM installation for mobile and fixed applications only. The antenna
installation and operating configurations of this transmitter, including any applicable source-based time-
averaging duty factor, antenna gain and cable loss must satisfy MPE categorical Exclusion Requirements
of 2.1091.
2. The EUT is a mobile device; maintain at least a 20 cm separation between the EUT and the user’s body
and must not transmit simultaneously with any other antenna or transmitter.
3.A label with the following statements must be attached to the host end product: This device contains
FCC ID: XMR201909EC21AUX.
4.To comply with FCC regulations limiting both maximum RF output power and human exposure to RF
radiation, maximum antenna gain (including cable loss) must not exceed:
❒ GSM850: <11.206dBi
❒ GSM1900: <12.140dBi
❒ WCDMA B2/LTE B2/ LTE B7: <8dBi
❒ WCDMA B4LTE B4: <5dBi
❒ WCDMA B5/LTE B5: <9.416dBi
5. This module must not transmit simultaneously with any other antenna or transmitter
6. The host end product must include a user manual that clearly defines operating requirements and
conditions that must be observed to ensure compliance with current FCC RF exposure guidelines.
For portable devices, in addition to the conditions 3 through 6 described above, a separate approval is
required to satisfy the SAR requirements of FCC Part 2.1093
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If the device is used for other equipment that separate approval is required for all other operating
configurations, including portable configurations with respect to 2.1093 and different antenna
configurations.
For this device, OEM integrators must be provided with labeling instructions of finished products.
Please refer to KDB784748 D01 v07, section 8. Page 6/7 last two paragraphs:
A certified modular has the option to use a permanently affixed label, or an electronic label. For a
permanently affixed label, the module must be labeled with an FCC ID - Section 2.926 (see 2.2
Certification (labeling requirements) above). The OEM manual must provide clear instructions
explaining to the OEM the labeling requirements, options and OEM user manual instructions that are
required (see next paragraph).
For a host using a certified modular with a standard fixed label, if (1) the module’s FCC ID is not visible
when installed in the host, or (2) if the host is marketed so that end users do not have straightforward
commonly used methods for access to remove the module so that the FCC ID of the module is visible;
then an additional permanent label referring to the enclosed module:“Contains Transmitter Module FCC
ID: XMR201909EC21AUX” or “Contains FCC ID: XMR201909EC21AUX” must be used. The host OEM
user manual must also contain clear instructions on how end users can find and/or access the module
and the FCC ID.
The final host / module combination may also need to be evaluated against the FCC Part 15B criteria
for unintentional radiators in order to be properly authorized for operation as a Part 15 digital device.
The user’s manual or instruction manual for an intentional or unintentional radiator shall caution the
user that changes or modifications not expressly approved by the party responsible for compliance
could void the user's authority to operate the equipment. In cases where the manual is provided only in
a form other than paper, such as on a computer disk or over the Internet, the information required by
this section may be included in the manual in that alternative form, provided the user can reasonably be
expected to have the capability to access information in that form.
This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions:
EC21_Hardware_Design 16 / 120
LTE Standard Module Series
EC21 Hardware Design
(1) This device may not cause harmful interference, and (2) this device must accept any interference
received, including interference that may cause undesired operation.
Changes or modifications not expressly approved by the manufacturer could void the user’s authority to
operate the equipment.
To ensure compliance with all non-transmitter functions the host manufacturer is responsible for ensuring
compliance with the module(s) installed and fully operational. For example, if a host was previously
authorized as an unintentional radiator under the Declaration of Conformity procedure without a
transmitter certified module and a module is added, the host manufacturer is responsible for ensuring that
the after the module is installed and operational the host continues to be compliant with the Part 15B
unintentional radiator requirements.
EC21_Hardware_Design 17 / 120
LTE Standard Module Series
EC21 Hardware Design
2 Product Concept
2.1. General Description
EC21 is a series of LTE-FDD/LTE-TDD/WCDMA/GSM wireless communication module with receive
diversity. It provides data connectivity on LTE-FDD, LTE-TDD, DC-HSDPA, HSPA+, HSDPA, HSUPA,
WCDMA, EDGE and GPRS networks. It also provides GNSS
specific applications. EC21 contains 11 variants: EC21-E, EC21-A, EC21-V, EC21-AU, EC21-EU,
EC21-EC, EC21-AUT, EC21-AUV, EC21-J, EC21-KL and EC21-AUX. Customers can choose a dedicated
type based on the region or operator. The following table shows the frequency bands of EC21 series
module.
1)
and voice functionality2) for customers’
Table 1: Frequency Bands of EC21 Series Module
Modules2) LTE Bands
EC21-E
EC21-A
EC21-V
EC21-AU3)
EC21-EU
EC21-AUT
EC21-EC
EC21-AUV
EC21-J
FDD:
B1/B3/B5/B7/B8/B20
FDD: B2/B4/B12 B2/B4/B5 N Y
FDD: B4/B13 N N Y
FDD:
B1/B2/B3/B4/B5/B7/B8/
B28
TDD: B40
FDD:
B1/B3/B7/B8/B20/B28A
FDD:
B1/B3/B5/B7/B28
FDD:
B1/B3/B7/B8/B20/B28A
FDD:
B1/B3/B5/B8/B28
FDD:
B1/B3/B8/B18/B19/B26
WCDMA
Bands
B1/B5/B8 900/1800MHz Y
B1/B2/B5/B8
B1/B8 900/1800MHz Y
B1/B5 N Y
B1/B8 900/1800MHz Y N
B1/B5/B8 N Y N
N N Y N
GSM Bands
850/900/
1800/1900MHz
Rxdiversity
Y
GNSS1)
GPS,
GLONASS,
BeiDou/
Compass,
Galileo,
QZSS
EC21_Hardware_Design 18 / 120
LTE Standard Module Series
EC21 Hardware Design
EC21-KL
FDD:
B1/B3/B5/B7/B8
N N Y N
FDD:
EC21-AUX3)
B1/B2/B3/B4/B5/B7/B8/
B28
B1/B2/B4/B5/
B8
850/900/
1800/1900MHz
Y Y
TDD: B40
NOTES
1)
1.
GNSS function is optional.
2)
2.
EC21 series module contains Telematics version and Data-only version. Telematics version
supports voice and data functions, while Data-only version only supports data function.
3. 3) B2 band on EC21-AU and EC21-AUX module does not support Rx-diversity. Additionally,
EC21-AUX is based on ThreadX OS.
4. Y = Supported. N = Not supported.
With a compact profile of 29.0mm × 32.0mm × 2.4mm, EC21 can meet almost all requirements for M2M
applications such as automotive, metering, tracking system, security, router, wireless POS, mobile
computing device, PDA phone, tablet PC, etc.
EC21 is an SMD type module which can be embedded into applications through its 144-pin pads,
including 80 LCC signal pads and 64 LGA pads.
2.2. Key Features
The following table describes the detailed features of EC21 module.
Table 2: Key Features of EC21 Module
Features Details
Power Supply
Transmitting Power
Supply voltage: 3.3V~4.3V
Typical supply voltage: 3.8V
Class 4 (33dBm±2dB) for GSM850
Class 4 (33dBm±2dB) for EGSM900
Class 1 (30dBm±2dB) for DCS1800
Class 1 (30dBm±2dB) for PCS1900
Class E2 (27dBm±3dB) for GSM850 8-PSK
Class E2 (27dBm±3dB) for EGSM900 8-PSK
Class E2 (26dBm±3dB) for DCS1800 8-PSK
Class E2 (26dBm±3dB) for PCS1900 8-PSK
EC21_Hardware_Design 19 / 120
LTE Standard Module Series
EC21 Hardware Design
Class 3 (24dBm+1/-3dB) for WCDMA bands
Class 3 (23dBm±2dB) for LTE-FDD bands
Class 3 (23dBm±2dB) for LTE-TDD bands
Support up to non-CA Cat 1 FDD and TDD
Support 1.4/3/5/10/15/20MHz RF bandwidth
LTE Features
Support MIMO in DL direction
LTE-FDD: Max 10Mbps (DL)/Max 5Mbps (UL)
LTE-TDD: Max 8.96Mbps (DL)/Max 3.1Mbps (UL)
Support 3GPP R8 DC-HSDPA, HSPA+, HSDPA, HSUPA and WCDMA
Support QPSK, 16-QAM and 64-QAM modulation
UMTS Features
DC-HSDPA: Max 42Mbps (DL)
HSUPA: Max 5.76Mbps (UL)
WCDMA: Max 384Kbps (DL)/Max 384Kbps (UL)
GPRS:
Support GPRS multi-slot class 33 (33 by default)
Coding scheme: CS-1, CS-2, CS-3 and CS-4
Max 107Kbps (DL)/Max 85.6Kbps (UL)
EDGE:
GSM Features
Support EDGE multi-slot class 33 (33 by default)
Support GMSK and 8-PSK for different MCS (Modulation and Coding
Scheme)
Downlink coding schemes: CS 1-4 and MCS 1-9
Uplink coding schemes: CS 1-4 and MCS 1-9
Max 296Kbps (DL)/Max 236.8Kbps (UL)
Support TCP/UDP/PPP/FTP/FTPS/HTTP/HTTPS/NTP/PING/QMI/NITZ/
MMS/SMTP/SSL/MQTT/FILE/CMUX*/SMTPS* protocols
Internet Protocol Features
Support PAP (Password Authentication Protocol) and CHAP (Challenge
Handshake Authentication Protocol) protocols which are usually used for
PPP connections
Text and PDU mode
SMS
Point to point MO and MT
SMS cell broadcast
SMS storage: ME by default
(U)SIM Interface Support USIM/SIM card: 1.8V, 3.0V
Support one digital audio interface: PCM interface
GSM: HR/FR/EFR/AMR/AMR-WB
Audio Features
WCDMA: AMR/AMR-WB
LTE: AMR/AMR-WB
Support echo cancellation and noise suppression
Used for audio function with external codec
PCM Interface
Support 16-bit linear data format
Support long frame synchronization and short frame synchronization
Support master and slave modes, but must be the master in long frame
EC21_Hardware_Design 20 / 120
LTE Standard Module Series
EC21 Hardware Design
synchronization
Compliant with USB 2.0 specification (slave only); the data transfer rate
can reach up to 480Mbps
USB Interface
Used for AT command communication, data transmission, GNSS NMEA
output, software debugging, firmware upgrade and voice over USB
Support USB serial drivers for: Windows 7/8/8.1/10, Linux 2.6/3.x/4.1~4.15,
Android 4.x/5.x/6.x/7.x/8.x/9.x, etc.
Main UART:
Used for AT command communication and data transmission
Baud rates reach up to 921600bps, 115200bps by default
UART Interfaces
Support RTS and CTS hardware flow control
Debug UART:
Used for Linux console and log output
115200bps baud rate
SD Card Interface1)
Support SD 3.0 protocol
SGMII Interface1) Support 10M/100M/1000M Ethernet work mode
Wireless Connectivity
Interfaces
1)
Support a low-power SDIO 3.0 interface for WLAN and UART/PCM
interfaces for Bluetooth
Rx-diversity Support LTE/WCDMA Rx-diversity
GNSS Features
AT Commands
Network Indication
Antenna Interfaces
Physical Characteristics
Temperature Range
Gen8C Lite of Qualcomm
Protocol: NMEA 0183
Compliant with 3GPP TS 27.007, 27.005 and Quectel enhanced AT
commands
Two pins including NET_MODE and NET_STATUS to indicate network
connectivity status
Including main antenna interface (ANT_MAIN), Rx-diversity antenna
interface (ANT_DIV) and GNSS antenna interface (ANT_GNSS)
Size: (29.0±0.15)mm × (32.0±0.15)mm × (2.4±0.2)mm
Weight: approx. 4.9g
2)
Operation temperature range: -35°C ~ +75°C
Extended temperature range: -40°C ~ +85°C
3)
Storage temperature range: -40°C ~ +90°C
Firmware Upgrade USB interface or DFOTA*
RoHS All hardware components are fully compliant with EU RoHS directive
EC21_Hardware_Design 21 / 120
LTE Standard Module Series
EC21 Hardware Design
NOTES
1)
1.
SD card, wireless connectivity and SGMII interfaces are not supported on ThreadX module.
2. 2) Within operation temperature range, the module is 3GPP compliant.
3. 3) Within extended temperature range, the module remains the ability to establish and maintain a
voice, SMS, data transmission, emergency call* (emergency call is not supported on ThreadX
module), etc. There is no unrecoverable malfunction. There are also no effects on radio spectrum
and no harm to radio network. Only one or more parameters like P
might reduce in their value and
out
exceed the specified tolerances. When the temperature returns to normal operation temperature
levels, the module will meet 3GPP specifications again.
4. “*” means under development.
2.3. Functional Diagram
The following figure shows a block diagram of EC21 and illustrates the major functional parts.
Power management
Baseband
DDR+NAND flash
Radio frequency
Peripheral interfaces
EC21_Hardware_Design 22 / 120
LTE Standard Module Series
EC21 Hardware Design
ANT_MAIN ANT_DIVANT_GNSS
VBAT_RF
VBAT_BB
PWRKEY
RESET_N
ADCs
STATUS
APT
PMIC
VDD_EXT
SAW
Tx
Control
19.2M
PAM
Duplex
PA
PRx DRx
Transceiver
IQ Cont rol
XO
USB (U)SIM PCM UARTsI2C
SAW
LNA
Switch
SAW
Baseband
SGMII
NAND
DDR2
SDRAM
WLAN SDBT
GPIOs
Figure 1: Functional Diagram
2.4. Evaluation Board
In order to help customers develop applications with EC21, Quectel supplies an evaluation board
(UMTS<E EVB), USB to RS-232 converter cable, earphone, antenna and other peripherals to control
or test the module. For more details, please refer to document [8].
EC21_Hardware_Design 23 / 120
LTE Standard Module Series
EC21 Hardware Design
3 Application Interfaces
3.1. General Description
EC21 is equipped with 80 LCC pads plus 64 LGA pads that can be connected to cellular application
platform. The subsequent chapters will provide detailed descriptions of the following functions/pins/
interfaces.
Power supply
(U)SIM interface
USB interface
UART interfaces
PCM and I2C interfaces
SD card interface
ADC interfaces
Status indication
SGMII interface
Wireless connectivity interfaces
USB_BOOT interface
1)
1)
1)
NOTE
1)
SD card, wireless connectivity and SGMII interfaces are not supported on ThreadX module.
EC21_Hardware_Design 24 / 120
LTE Standard Module Series
EC21 Hardware Design
3.2. Pin Assignment
The following figure shows the pin assignment of EC21 module.
RESERVED
WA KEUP _I N
AP _REA D Y
RESERVED
W_ DI SABL E#
NET_MODE
NET _ST AT US
VDD _EX T
RESERVED
RESERVED
GND
GND
USIM_GND
DBG_RXD
DBG_TX D
USIM_PRESENCE
USIM_VDD
USIM_DATA
USIM_CLK
USIM_RST
RESERVED
RESERVED
11 4
1)
1
2
129
130
4
1)
5
131
6
132
7
14 1
14 2
133
134
8
9
135
10
11
12
13
14
15
16
17
18
136
137
138
139
140
1)
1)
1)
11 6
RESERVED
USB_VBUS
USB_DM
USB_DP
GND
11 3
7271706968676665646362616059585756
117
10 8
118
119
120
10 9
121
122
11 0
123
124
11 1
125
126
127
11 2
128
11 5
20212223242526272829303132
19
RESET_N
USB_BOOT
GND
PW RKEY
10 3
10 4
10 5
10 6
10 7
GND
RXD
TXD
82
83
84
SD _I NS_D ET
PCM _I N3)PCM _OU T3)PCM _SY NC3)PCM _C LK
DTR
99
10 0
10 1
10 2
DCD
CTS
RTS
95
96
73
76
79
74
80
77
78
81
75
97
98
SDC2_DATA3
VB AT _BB
VB AT _BB
ST ATU S
RI
90
91
92
93
94
SDC2_DATA2
SDC2_DATA1
SDC2_DATA0
SDC2_CLK
VB AT_ RF
85
86
87
88
89
33
SDC2_CMD
VB AT_ RF
34335
VDD _SD IO
RESERVED
GND
55
GND
54
GND
53
GND
52
GND
51
GND
50
ANT _M AI N
49
GND
48
RESERVED
14 4
RESERVED
14 3
47
ANT _G NSS
GND
46
ADC 0
45
ADC 1
44
RESERVED
43
I2C_SDA
42
I2C_SCL
41
40
39
38
37
36
GND
ANT _D IV
BT _CT S
BT _R XD
BT _TX D
BT _RT S
1)
1)
Powe r Pi ns Si g na l Pin s
GND Pins
2)
Bluetooth Pins
3)
WLAN Pins RESERVED Pins
SG MI I Pi ns
Figure 2: Pin Assignment (Top View)
NOTES
1. 1) means pins WAKEUP_IN, NET_MODE, WLAN_EN, COEX_UART_RX, COEX_UART_TX,
USB_BOOT and BT_CTS cannot be pulled up before startup.
2)
2.
PWRKEY output voltage is 0.8V because of the diode drop in the Qualcomm chipset.
3)
3.
means digital audio (PCM) is only supported on Telematics version.
4. Pins 37~40, 118, 127 and 129~139 are used for wireless connectivity interfaces, among which pads
118, 127 and 129~138 are WLAN function pins, and the rest are Bluetooth (BT) function pins. BT
function is under development.
EC21_Hardware_Design 25 / 120
LTE Standard Module Series
EC21 Hardware Design
5. Pins 119~126 and 128 are used for SGMII interface.
6. Pins 24~27 for PCM function are multiplexing pins used for audio design on EC21 module and BT
function on FC20 module.
7. SD card, wireless connectivity and SGMII interfaces (pins 37~40, 118, 127, 129~139, 119~126, 128,
23, 28~34) are not supported on ThreadX module.
8. Keep all RESERVED pins and unused pins unconnected.
9. GND pads 85~112 should be connected to ground in the design. RESERVED pads 73~84 should not
be designed in schematic and PCB decal, and these pins should be served as a keepout area.
3.3. Pin Description
The following tables show the pin definition of EC21 module.
Table 3: I/O Parameters Definition
Type Description
AI Analog Input
AO Analog Output
DI Digital Input
DO Digital Output
IO Bidirectional
OD Open Drain
PI Power Input
PO Power Output
Table 4: Pin Description
Power Supply
Pin Name Pin No. I/O Description DC Characteristics Comment
VBAT_BB 59, 60 PI
Power supply for
module’s baseband
part
Vmax=4.3V
Vmin=3.3V
Vnorm=3.8V
It must be provided with
sufficient current up to
0.8A.
EC21_Hardware_Design 26 / 120
LTE Standard Module Series
EC21 Hardware Design
It must be provided with
sufficient current up to
1.8A in a burst
transmission.
VBAT_RF 57, 58 PI
Power supply for
module’s RF part
Vmax=4.3V
Vmin=3.3V
Vnorm=3.8V
Power supply for
VDD_EXT 7 PO
Provide 1.8V for
external circuit
Vnorm=1.8V
I
max=50mA
O
external GPIO’s pull-up
circuits.
If unused, keep it open.
8, 9, 19,
22, 36, 46,
GND
48, 50~54,
Ground
56, 72,
85~112
Power-on/off
Pin Name Pin No. I/O Description DC Characteristics Comment
The output voltage is
PWRKEY 21 DI
Turn on/off the
module
V
H
=0.8V
0.8V because of the
diode drop in the
Qualcomm chipset.
V
max=2.1V
IH
V
min=1.3V
IH
V
max=0.5V
IL
If unused, keep it
open.
RESET_N 20 DI
Reset signal of the
module
Status Indication
Pin Name Pin No. I/O Description DC Characteristics Comment
An external pull-up
resistor is required.
If unused, keep it
open.
STATUS 61 OD
Indicate the module
operating status
The drive current
should be less than
0.9mA.
1.8V power domain.
It cannot be pulled up
before startup.
If unused, keep it
NET_MODE 5 DO
Indicate the
module’s network
registration mode
V
min=1.35V
OH
V
max=0.45V
OL
open.
NET_
STATUS
Indicate the
6 DO
module’s network
activity status
V
min=1.35V
OH
V
max=0.45V
OL
1.8V power domain.
If unused, keep it
open.
USB Interface
Pin Name Pin No. I/O Description DC Characteristics Comment
EC21_Hardware_Design 27 / 120
LTE Standard Module Series
EC21 Hardware Design
USB power supply,
USB_VBUS 71 PI
used for USB
detection
USB_DP 69 IO
USB_DM 70 IO
USB differential data
bus (+)
USB differential data
bus (-)
Vmax=5.25V
Vmin=3.0V
Vnorm=5.0V
Compliant with USB
2.0 standard
specification.
Compliant with USB
2.0 standard
specification.
Typical: 5.0V
If unused, keep it
open.
Require differential
impedance of 90Ω.
If unused, keep it
open.
Require differential
impedance of 90Ω.
If unused, keep it
open.
(U)SIM Interface
Pin Name Pin No. I/O Description DC Characteristics Comment
USIM_GND 10
Specified ground for
(U)SIM card
For 1.8V (U)SIM:
Vmax=1.9V
USIM_VDD 14 PO
Power supply for
(U)SIM card
Vmin=1.7V
For 3.0V (U)SIM:
Vmax=3.05V
Either 1.8V or 3.0V is
supported by the
module automatically.
Vmin=2.7V
IOmax=50mA
USIM_DATA 15 IO
USIM_CLK 16 DO
Data signal of
(U)SIM card
Clock signal of
(U)SIM card
For 1.8V (U)SIM:
V
max=0.6V
IL
V
min=1.2V
IH
V
max=0.45V
OL
V
min=1.35V
OH
For 3.0V (U)SIM:
max=1.0V
V
IL
V
min=1.95V
IH
V
max=0.45V
OL
V
min=2.55V
OH
For 1.8V (U)SIM:
V
max=0.45V
OL
V
min=1.35V
OH
For 3.0V (U)SIM:
max=0.45V
V
OL
V
min=2.55V
OH
EC21_Hardware_Design 28 / 120
LTE Standard Module Series
EC21 Hardware Design
For 1.8V (U)SIM:
max=0.45V
V
OL
V
min=1.35V
OH
For 3.0V (U)SIM:
max=0.45V
V
OL
V
min=2.55V
OH
V
min=-0.3V
IL
V
max=0.6V
IL
V
min=1.2V
IH
V
max=2.0V
IH
1.8V power domain.
If unused, keep it
open.
USIM_RST 17 DO
USIM_
PRESENCE
13 DI
Reset signal of
(U)SIM card
(U)SIM card
insertion detection
Main UART Interface
Pin Name Pin No. I/O Description DC Characteristics Comment
V
RI 62 DO Ring indicator
DCD 63 DO
Data carrier
detection
CTS 64 DO Clear to send
RTS 65 DI Request to send
DTR 66 DI
Data terminal ready,
sleep mode control
OL
V
OH
V
OL
V
OH
V
OL
V
OH
V
IL
V
IL
V
IH
V
IH
V
IL
V
IL
V
IH
V
IH
max=0.45V
min=1.35V
max=0.45V
min=1.35V
max=0.45V
min=1.35V
min=-0.3V
max=0.6V
min=1.2V
max=2.0V
min=-0.3V
max=0.6V
min=1.2V
max=2.0V
1.8V power domain.
If unused, keep it
open.
1.8V power domain.
If unused, keep it
open.
1.8V power domain.
If unused, keep it
open.
1.8V power domain.
If unused, keep it
open.
1.8V power domain.
Pulled up by default.
Low level wakes up
the module.
If unused, keep it
open.
1.8V power domain.
If unused, keep it
open.
1.8V power domain.
If unused, keep it
open.
TXD 67 DO Transmit data
RXD 68 DI Receive data
V
max=0.45V
OL
V
min=1.35V
OH
V
min=-0.3V
IL
V
max=0.6V
IL
V
min=1.2V
IH
V
max=2.0V
IH
Debug UART Interface
EC21_Hardware_Design 29 / 120
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