LD SIM last dialing phonebook (list of numbers most recently dialed)
MC Mobile Equipment list of unanswered MT calls (missed calls)
ON
SIM (or ME) own numbers (MSISDNs) list
RC Mobile Equipment list of received calls
SM SIM phonebook
NC Not connect
SIM300_HD_V3.02 Page 10 of 56
SIM300 Hardware Interface Description
Confidential
SIMCOM
2 Product concept
Designed for global market, SIM300 is a Tri-band GSM/GPRS engine that works on frequencies
EGSM 900 MHz, DCS 1800 MHz and PCS1900 MHz. SIM300 provides GPRS multi-slot class
10/ class 8 (optional) capability and support the GPRS coding schemes CS-1, CS-2, CS-3 and
CS-4.
With a tiny configuration of 40mm x 33mm x 2.85 mm , SIM300 can fit almost all the space
requirement in your application, such as Smart phone, PDA phone and other mobile device.
The physical interface to the mobile application is made through a 60 pins board-to-board
connector, which provides all hardware interfaces between the module and customers’ boards
except the RF antenna interface.
zThe keypad and SPI LCD interface will give you the flexibility to develop customized
applications.
z Two serial ports can help you easily develop your applications.
z Two audio channels include two microphones inputs and two speaker outputs. This can
be easily configured by AT command.
SIM300 provide RF antenna interface with two alternatives: antenna connector and antenna pad.
The antenna connector is MURATA MM9329-2700. And customer’s antenna can be soldered to
the antenna pad.
The SIM300 is designed with power saving technique, the current consumption to as low as
2.5mA in SLEEP mode.
The SIM300 is integrated with the TCP/IP protocol,Extended TCP/IP AT commands are
developed for customers to use the TCP/IP protocol easily, which is very useful for those data
transfer applications.
SIM300_HD_V3.02 Page 11 of 56
SIM300 Hardware Interface Description
Confidential
SIMCOM
2.1 SIM300 key features at a glance
Table 3: SIM300 key features
Feature Implementation
Power supply Single supply voltage 3.4V – 4.5V
Power saving Typical power consumption in SLEEP mode to 2.5mA
Frequency bands
GSM class Small MS
Transmit power z Class 4 (2W) at EGSM900
GPRS connectivity
Temperature range
DATA GPRS:
CSD:
zSIM300 Tri-band: EGSM 900, DCS 1800, PCS 1900. The band
can be set by AT COMMAND, and default band is EGSM 900
and DCS 1800.
z Compliant to GSM Phase 2/2+
z Class 1 (1W) at DCS1800 and PCS 1900
z GPRS multi-slot class 10 (default)
z GPRS multi-slot class 8 (option)
z GPRS mobile station class B
z Normal operation:-20°C to +55°C
z Restricted operation: -30°C to -20°C and +55°C to +80°C
z Storage temperature -40°C to +85°C
z GPRS data downlink transfer: max. 85.6 kbps
z GPRS data uplink transfer: max. 42.8 kbps
z Coding scheme: CS-1, CS-2, CS-3 and CS-4
z SIM300 supports the protocols PAP (Password Authentication
Protocol) usually used for PPP connections.
z The SIM300 integrates the TCP/IP protocol.
z Support Packet Switched Broadcast Control Channel (PBCCH)
z CSD transmission rates: 2.4, 4.8, 9.6, 14.4 kbps, non-transparent
z Unstructured Supplementary Services Data (USSD) support
SMS z MT, MO, CB, Text and PDU mode
z SMS storage: SIM card
z Support transmission of SMS alternatively over CSD or GPRS.
User can choose preferred mode.
FAX Group 3 Class 1
SIM interface Supported SIM card: 1.8V ,3V
External antenna Connected via 50 Ohm antenna connector or antenna pad
Audio features Speech codec modes:
z Half Rate (ETS 06.20)
z Full Rate (ETS 06.10)
z Enhanced Full Rate (ETS 06.50 / 06.60 / 06.80)
z Echo suppression
Two serial interfaces z Serial Port 1 Seven lines on Serial Port Interface
SIM300_HD_V3.02 Page 12 of 56
SIM300 Hardware Interface Description
Confidential
SIMCOM
zSerial Port 1 can be used for CSD FAX, GPRS service and send
AT command of controlling module.
zSerial Port 1 can use multiplexing function, but you can not use
the Serial Port 2 at the same time;
z Autobauding supports baud rate from 1200 bps to 115200bps.
z Serial port 2 Two lines on Serial Port Interface /TXD and /RXD
z Serial Port 2 only used for transmitting AT command.
SIM Application Toolkit Supports SAT class 3, GSM 11.14 Release 98
Real time clock Implemented
Timer function Programmable via AT command
Physical characteristics Size: 40±0.15 x 33±0.15 x 3.3±0.3 mm (including application
connector)
40±0.15 x 33±0.15 x 2.85±0.3 mm (excluding application connector)
Weight: 8g
Firmware upgrade Firmware upgradeable over serial interface
Table 4: Coding schemes and maximum net data rates over air interface
Coding scheme 1 Timeslot 2 Timeslot 4 Timeslot
CS-1: 9.05kbps 18.1kbps 36.2kbps
CS-2: 13.4kbps 26.8kbps 53.6kbps
CS-3: 15.6kbps 31.2kbps 62.4kbps
CS-4: 21.4kbps 42.8kbps 85.6kbps
SIM300_HD_V3.02 Page 13 of 56
SIM300 Hardware Interface Description
Confidential
SIMCOM
3 Application Interface
All hardware interfaces except RF interface that connects SIM300 to the customers’ cellular
application platform is through a 60-pin 0.5mm pitch board-to-board connector. Sub-interfaces
included in this board-to-board connector are described in detail in following chapters:
z Power supply (see Chapters 3.3)
z Dual serial interface (
z Two analog audio interfaces (
z SIM interface (
Electrical and mechanical characteristics of the board-to-board connector are specified in Chapter
6. There we also order information for mating connectors.
see Chapter 3.8)
see Chapter 3.9)
see Chapter 3.11)
3.1 SIM300 Pin description
Table 5: Board-to-Board Connector pin description
Power Supply
PIN NAME I/O DESCRIPTION DC CHARACTERISTICS
VBAT Eight BAT pins of the board-to-board
connector are dedicated to connect
the supply voltage. The power supply
of SIM300 has to be a single voltage
source of VBAT= 3.4V...4.5V. It must
be able to provide sufficient current
in a transmit burst which typically
rises to 2A.mostly, these 8 pins are
voltage input
VRTC I/O Current input for RTC when the
battery is not supplied for the system.
Current output for backup battery
when the main battery is present and
the backup battery in low voltage
state.
Vmax= 4.5V
Vmin=3.4V
Vnorm=4.0V
Vmax=2.0V
Vmin=1.2V
Vnorm=1.8V
Inorm= 20uA
VDD_EXT O Supply 2.93V voltage for external
circuit. By measure this pin, user
can judge the system is on or off.
When the voltage is low, the system
is off. Otherwise, the system is on.
GND Digital ground
SIM300_HD_V3.02 Page 14 of 56
Vmax=3.0V
Vmin=2.75V
Vnorm=2.93V
Imax=60mA
SIM300 Hardware Interface Description
Confidential
SIMCOM
Power on or power off
PIN NAME I/O DESCRIPTION DC CHARACTERISTICS
PWRKEY I Voltage input for power on key.
PWRKEY get a low level Voltage for
user to power on or power off the
VILmax=0.3*VBAT
VIHmin=0.7*VBAT
VImax=VBAT
system, The user should keep
pressing the key for a moment when
power on or power off the system.
Because the system need margin time
assert the software.
Audio interfaces
PIN NAME I/O DESCRIPTION DC CHARACTERISTICS
MIC1P
MIC1N
MIC2P
MIC2N
SPK1P
SPK1N
SPK2P
SPK2N
I Positive and negative voice-band
input
I Auxiliary positive and negative
voice-band input
O Positive and negative voice-band
output
O Auxiliary positive and negative
voice-band output
Audio DC Characteristics
refer to chapter 3.9.4
Buzzer/GPIO8O Buzzer Output
AGND Analog ground
General purpose input/output
PIN NAME I/O DESCRIPTION DC CHARACTERISTICS
KBC0~KBC4 O
KBR0~KBR4 I
SPI_DATA I/O
SPI_CLK O
SPI_CS O
SPI_D/C O
SPI_RST O
Network LED
O
The GPO can be configured by AT
command for outputting high or low
level voltage. All of the GPOs are
initial low without any setting from
AT command.
VILmin=0V
VILmax=0.3 *VDD_EXT
VIHmin=0.7*VDD_EXT
VIHmax= VDD_EXT+0.3
VOLmin=GND
VOLmax=0.2V
VOHmin= VDD_EXT-0.2
VOHmax= VDD_EXT
GPIO5I/O Normal Input/Output Port
Serial 1 interface
PIN NAME I/O DESCRIPTION DC CHARACTERISTICS
DTR I Data Terminal Ready
RXD I Receive Data
TXD O Transmit Data
RTS I Request to Send
VILmin=0V
VILmax=0.3*VDD_EXT
VIHmin=0.7*VDD_EXT
VIHmax= VDD_EXT+0.3
VOLmin=GND
CTS O Clear to Send
SIM300_HD_V3.02 Page 15 of 56
SIM300 Hardware Interface Description
Confidential
SIMCOM
RI O Ring Indicator
DCD
O Data Carrier detection
Serial 2 interface
DBGTX O
Serial interface for debugging and
VOLmax=0.2V
VOHmin= VDD_EXT-0.2
VOHmax= VDD_EXT
communication
DBGRX I
SIM interface
PIN NAME I/O DESCRIPTION DC CHARACTERISTICS
SIM_VDD O Voltage Supply for SIM card The voltage can be select
by software either 1.8v or
3V
SIM_I/O I/O SIM Data Output
SIM_CLK O SIM Clock
SIM_PRESENCE I SIM Card Detection
SIM_RST O SIM Reset
VILmin=0V
VILmax=0.3*SIM_VDD
VIHmin=0.7*SIM_VDD
VIHmax= SIM_VDD+0.3
VOLmin=GND
VOLmax=0.2V
VOHmin= SIM_VDD-0.2
VOHmax= SIM_VDD
AUXADC
PIN NAME I/O DESCRIPTION DC CHARACTERISTICS
ADC0 I General purpose analog to digital
converter.
Input voltage value scope
0V to 2.4V
3.2 Operating modes
The following table summarizes the various operating modes, each operating modes is referred to
in the following chapters.
Table 6: Overview of operating modes
Mode Function
Normal operation GSM/GPRS
SLEEP
Module will automatically go into SLEEP mode if DTR is set
to high level and there is no on air or audio activity is required
and no hardware interrupt (such as GPIO interrupt or data on
serial port).
In this case, the current consumption of module will reduce to
the minimal level.
During sleep mode, the module can still receive paging
message and SMS from the system normally.
SIM300_HD_V3.02 Page 16 of 56
SIM300 Hardware Interface Description
Confidential
SIMCOM
GSM IDLE Software is active. Module has registered to the GSM network,
and the module is ready to send and receive.
GSM TALK CSD connection is going on between two subscribers. In this
case, the power consumption depends on network settings such
as DTX off/on, FR/EFR/HR, hopping sequences, antenna.
GPRS IDLE Module is ready for GPRS data transfer, but no data is
currently sent or received. In this case, power consumption
depends on network settings and GPRS configuration (e.g.
multi-slot settings).
GPRS DATA There is GPRS data in transfer (PPP or TCP or UDP). In this
case, power consumption is related with network settings (e.g.
power control level), uplink / downlink data rates and GPRS
configuration (e.g. used multi-slot settings).
POWER DOWN Normal shutdown by sending the “AT+CPOWD=1” command or using the
PERKEY. The power management ASIC disconnects the power supply from the
base band part of the module, only the power supply for the RTC is remained.
Software is not active. The serial interfaces are not accessible. Operating voltage
(connected to VBAT) remains applied.
Minimum
functionality
mode (without
remove power
supply)
Use the “AT+CFUN” command can set the module to a minimum functionality
mode without remove the power supply. In this case, the RF part of the module
will not work or the SIM card is not accessible, or RF part and SIM card be
closed all, the serial interfaces is still accessible. The power consumption in this
case is very low.
Alarm mode RTC alert function launches this restricted operation while the module is in
POWER DOWN mode. SIM300 will not be registered to GSM network and
only parts of AT commands can be available.
3.3 Power supply
The power supply of SIM300 is from a single voltage source of VBAT= 3.4V...4.5V. In some
case, the ripple in a transmit burst may cause voltage drops when current consumption rises to
typical peaks of 2A, So the power supply must be able to provide sufficient current up to 2A.
For the VBAT input, a local bypass capacitor is recommended. A capacitor (about 100µF, low
ESR) is recommended. Multi-layer ceramic chip (MLCC) capacitors can provide the best
combination of low ESR and small size but may not be cost effective. A lower cost choice may be
a 100 µF tantalum capacitor (low ESR) with a small (1 µF to 10µF) ceramic in parallel, which is
illustrated as following figure. And the capacitors should put as closer as possible to the SIM300
VBAT pins. The following figure is the recommended circuit.
SIM300_HD_V3.02 Page 17 of 56
SIM300 Hardware Interface Description
Confidential
SIMCOM
Figure 1: VBAT input
The following figure is the VBAT voltage ripple wave at the maximum power transmit phase,
the test condition is VBAT=4.0V, VBAT maximum output current =2A, C
capacitor (ESR=0.7Ω) and C
=4.7µF. B
B
=100 µF tantalum
A
Figure2: VBAT ripple wave at the maximum power transmit phase
3.3.1 Power supply pins on the board-to-board connector
Eight VBAT pins of the board-to-board connector are dedicated to connect the supply voltage;
four GND pins are recommended for grounding. BACKUP can be used to back up the RTC.
3.3.2 Minimizing power losses
Please pay special attention to the supply power when you are designing your applications. Please
make sure that the input voltage will never drops below 3.4V even in a transmit burst during
which the current consumption may rise up to 2A. If the power voltage drops below 3.4V, the
module may be switched off. Using the board-to-board connector will be the best way to reduce
the voltage drops. You should also take the resistance of the power supply lines on the host board
or of battery pack into account.
SIM300_HD_V3.02 Page 18 of 56
SIM300 Hardware Interface Description
Confidential
3.3.3 Monitoring power supply
To monitor the supply voltage, you can use the “AT+CBC” command which include three
parameters: voltage percent and voltage value (in mV). It returns the battery voltage 1-100 percent
of capacity and actual value measured at VBAT and GND.
The voltage is continuously measured at intervals depending on the operating mode. The
displayed voltage (in mV) is averaged over the last measuring period before the AT+CBC
command was executed.
For details please refer to document [1]
SIMCOM
3.4 Power up and power down scenarios
3.4.1 Turn on SIM300
SIM300 can be turned on by various ways, which are described in following chapters:
z Via PWRKEY pin: starts normal operating mode (see chapter 3.4.1.1);
z Via RTC interrupt: starts ALARM modes (see chapter 3.4.1.2)
Note: The AT command must be set after the SIM300 is power on and Unsolicited Result
Code “RDY” is received from the serial port. But if the SIM300 was set autobauding, the
serial port received nothing, the AT command can be set after 2-3S from the SIM300 is
power on. You can use AT+IPR=x;&W to set a fix baud rate and save the configuration to
non-volatile flash memory. After the configuration was saved as fix baud rate, the Code
“RDY” should be received from the serial port all the time when the SIM300 was power on.
See Chapter AT+IPR in document [1].
3.4.1.1 Turn on SIM300 using the PWRKEY pin (Power on)
You can turn on the SIM300 by driving the PWRKEY to a low level voltage for period time. The
power on scenarios illustrate as following figure.
Figure 3: Timing of turn on system
SIM300_HD_V3.02 Page 19 of 56
SIM300 Hardware Interface Description
Confidential
When power on procedure complete, the SIM300 will send out following result code to indicate
the module is ready to operate when set fixed baud rate.
RDY
Note that if SIM300 was set as autobauding, the serial port sends nothing.
3.4.1.2 Turn on SIM300 using the RTC (Alarm mode)。
Alarm mode is a power-on approach by using the RTC. The alert function of RTC makes the
SIM300 wake up while the module is power off. In alarm mode, SIM300 will not register to GSM
network and the software protocol stack is close. Thus the parts of AT commands related with
SIM card and Protocol stack will not accessible, and the others can be used as well as in normal
mode.
Use the AT+CALARM command to set the alarm time. The RTC remains the alarm time if
SIM300 was power down by “AT+CPOWD=1” or by PWRKEY pin. Once the alarm time expires
and executed, SIM300 goes into the Alarm mode. In this case, SIM300 will send out an
Unsolicited Result Code (URC) when set fixed baud rate:
SIMCOM
RDY
ALARMMODE
During Alarm mode, using AT+CFUN command to query the status of software protocol stack; it
will return 0 which indicates that the protocol stack is closed. Then after 90S, SIM300 will power
down automatically. However, during Alarm mode, if the software protocol is started by
AT+CFUN=1, 1 command, the process of automatic power down will not available. In ALARM
mode, driving the PWRKEY to a low level voltage for a period will cause SIM300 to power down
(Please refer to the power down scenarios in 3.3.2.1).
The table follow briefly summarizes the AT commands that are used usually during alarm mode,
for details of the instructions refer to document [1]:
Table 7: AT commands used in Alarm mode
AT command USE
AT+CALARM Set alarm time
AT+CCLK Set data and time of RTC
AT + CP O W D Power down
AT+CFUN Start or close the protocol stack
SIM300_HD_V3.02 Page 20 of 56
SIM300 Hardware Interface Description
Confidential
SIMCOM
3.4.2 Turn off SIM300
Following procedure can be used to turn off the SIM300:
z Normal power down procedure: Turn off SIM300 using the PWRKEY pin
z Normal power down procedure: Turn off SIM300 using AT command
z Under-voltage automatic shutdown: Takes effect if Under-voltage is detected
z Over-temperature automatic shutdown: Takes effect if Over-temperature is detected
3.4.2.1 Turn off SIM300 using the PWRKEY pin (Power down)
You can turn off the SIM300 by driving the PWRKEY to a low level voltage for period time. The
power down scenarios illustrate as following Figure.
This procedure will let the module to log off from the network and allow the software to enter into
a secure state and save data before completely disconnect the power supply.
Before the completion of the switching off procedure the module will send out result code:
NORMAL POWER DOWN
After this moment, no any AT commands can be executed. Module enters the POWER DOWN
mode, only the RTC is still active. POWER DOWN can also be indicated by VDD_EXT pin,
which is a low level voltage in this mode.
Figure 4: Timing of turn off system
SIM300_HD_V3.02 Page 21 of 56
SIM300 Hardware Interface Description
Confidential
SIMCOM
3.4.2.2 Turn off SIM300 using AT command
You can use an AT command “AT+CPOWD=1” to turn off the module. This command will let
the module to log off from the network and allow the software to enter into a secure state and safe
data before completely disconnect the power supply.
Before switching off the module will send out result code:
NORMAL POWER DOWN
After this moment, no any AT commands can be executed. Module enters the POWER DOWN
mode, only the RTC is still active. POWER DOWN can also be indicated by VDD_EXT pin,
which is a low level voltage in this mode.
Please refer to document [1] for detail about the AT command of “AT+CPOWD”.
3.4.2.3 Under-voltage automatic shutdown
Software will constantly monitors the voltage applied on the VBAT, if the measured battery
voltage is no more than 3.5V, the following URC will be presented:
POWER LOW WARNNING
If the measured battery voltage is no more than 3.4V, the following URC will be presented:
POWER LOW DOWN
After this moment, no further more AT commands can be executed. The module will log off from
network and enters POWER DOWN mode, only the RTC is still active. POWER DOWN can also
be indicated by VDD_EXT pin, which is a low level voltage in this mode.
3.4.2.4 Over-temperature automatic shutdown
Software will constantly monitors the temperature of the module, if the measured temperature is
equal or higher than 80℃, the following URC will be presented:
+CMTE: 1
If the measured temperature is equal or lower than -30℃, the following URC will be presented:
+CMTE: -1
The uncritical temperature range is -35℃ to 85℃. If the measured temperature is equal or beyond
this range, the module will be automatic shutdown soon.
If the measured temperature is equal or higher than 85℃, the following URC will be presented:
+CMTE: 2
SIM300_HD_V3.02 Page 22 of 56
SIM300 Hardware Interface Description
Confidential
If the measured temperature is equal or lower than -35℃, the following URC will be presented:
+CMTE:-2
After this moment, no further more AT commands can be executed. The module will log off from
network and enters POWER DOWN mode, only the RTC is still active. POWER DOWN can also
be indicated by VDD_EXT pin, which is a low level voltage in this mode.
To monitor the temperature, you can use the “AT+CMTE” command to measure the temperature
when the module power on.
For details please refer to document [1]
3.4.3 Restart SIM300 using the PWRKEY pin
You can restart SIM300 by driving the PWRKEY to a low level voltage for period time, same as
turn on SIM300 using the PWRKEY pin. Before restart the SIM300, you need delay at least
500mS from detecting the VDD_EXT low level on. The restart scenarios illustrate as the
following figure.
SIMCOM
Figure 5: Timing of restart system
3.5 Power saving
There are two methods to achieve SIM300 module extreme low power. “AT+CFUN” is used to
set module into minimum functionality mode and /DTR hardware interface signal can be used to
set system to be SLEEP mode (or Slow clocking mode).
SIM300_HD_V3.02 Page 23 of 56
SIM300 Hardware Interface Description
Confidential
SIMCOM
3.5.1 Minimum functionality mode
Minimum functionality
mode reduces the functionality of the module to a minimum and, thus,
minimizes the current consumption to the lowest level. This mode is set with the “AT+CFUN”
command which provides the choice of the functionality levels <fun>=0,
1,4
z 0: minimum functionality;
z 1: full functionality (Default);
z 4: disable phone both transmit and receive RF circuits;
If SIM300 has been set to minimum functionality by “AT+CFUN=0”, then the RF function and
SIM card function will be closed, in this case, the serial ports is still accessible, but all AT
commands need RF function or SIM card function will not accessible.
If SIM300 has disable all RF function by “AT+CFUN=4”, then RF function will be closed, the
serial ports is still active in this case but all AT commands need RF function will not accessible.
When SIM300 is in minimum functionality or has been disable all RF functionality by
“AT+CFUN=4”, it can return to full functionality by “AT+CFUN=1”.
For Detailed info about “AT+CFUN”, please refer to [1].
3.5.2 Sleep mode (Slow Clocking mode)
Through DTR signal control SIM300 module to enter or exit the SLEEP mode in customer
applications.
When DTR is in high level, at the same time there is no on air or audio activity is required and no
hardware interrupt (such as GPIO interrupt or data on serial port), SIM300 will enter SLEEP mode
automatically. In this mode, SIM300 can still receive paging or SMS from network.
In SLEEP mode, the serial port is not accessible.
Note: For SIM300, it requests to set AT command “AT+CSCLK=1” to enable the sleep
mode; the default value is 0, that can’t make the module enter sleep mode, for more details
please refer to our AT command list.
3.5.3 Wake up SIM300 from SLEEP mode
When SIM300 is SLEEP mode, the following method can wake up the module.
zEnable DTR pin to wake up SIM300;
If DTR Pin is pull down to a low level,this signal will wake up SIM300 from power saving
mode. The serial port will be active after DTR change to low level about 20ms.
SIM300_HD_V3.02 Page 24 of 56
SIM300 Hardware Interface Description
Confidential
SIMCOM
z Receive a voice or data call from network to wake up SIM300;
z Receive a SMS from network to wake up SIM300
z RTC alarm expired to wake up SIM300;
3.6 Summary of state transitions (except SLEEP mode)
Table 8: Summary of state transitions
Further mode
Current mode
POWER
DOWN
Normal mode AT+CPOWD or use
Alarm mode Use PWRKEY pin or wait
POWER DOWN Normal modeAlarm mode
Use PWRKEY Switch on from POWER DOWN mode bye
RTC
Set alarm by “AT+CALARM”, and then
PWRKEY pin
Use AT+CFUN
module switch off
automatically
switch off the module. When the timer
expire, the module turn on and enter Alarm
mode
3.7 RTC backup
The RTC (Real Time Clock) power supply of module can be provided by an external battery or a
battery (rechargeable or non-chargeable) through the PIN15 on the board-to-board connector.
There is a 10K resistance has been integrated in SIM300 module used for restricting current. You
need only a coin-cell battery or a super-cap to PIN15 to backup power supply for RTC.
Note: The VRTC couldn’t be designed to a NC pin in your circuit. You should connect the
VRTC pin to a battery or a capacitor.
The following figures show various sample circuits for RTC backup.
6: RTC supply from non-chargeable battery
Figure
SIM300_HD_V3.02 Page 25 of 56
SIM300 Hardware Interface Description
Confidential
SIMCOM
7: RTC supply from rechargeable battery
Figure
8: RTC supply from capacitor
Figure
zLi-battery backup
Rechargeable Lithium coin cells such as the TC614 from Maxell, or the TS621 from Seiko, are
also small in size, but have higher capacity than the double layer capacitors resulting in longer
backup times.
Typical charge curves for each cell type are shown in following figures. Note that the rechargeable
Lithium type coin cells generally come pre-charged from the vendor.
enabled. This gives you the flexibility to put the GSM engine into operation no matter what bit
rate your host application is configured to. To take advantage of autobaud mode specific attention
must be paid to the following requirements:
Synchronization between DTE and DCE.
Ensure that DTE and DCE are correctly synchronized and the bit rate used by the DTE is detected
by the DCE (= ME). To allow the bit rate to be synchronized simply issue an "AT" or "at" string.
This is necessary.
z after you have activated autobauding
z when you start up the GSM engine while autobauding is enabled. It is recommended to wait 3
to 5 seconds before sending the first AT character. Otherwise undefined characters might be
returned.
Restrictions on autobauding operation
z The serial interface has to be operated at 8 data bits, no parity and 1 stop bit (factory setting).
z The Unsolicited Result Codes like "RDY", "+CFUN: 1" and "+CPIN: READY” are not
indicated when you start up the ME while autobauding is enabled. This is due to the fact that
the new bit rate is not detected unless DTE and DCE are correctly synchronized as described
above.
Note: You can use AT+IPR=x;&W to set a fix baud rate and save the configuration to
non-volatile flash memory. After the configuration was saved as fix baud rate, the Unsolicited
Result Codes like "RDY" should be received from the serial port all the time when the SIM300
was power on.
Serial port 2
z Two lines on Serial Port Interface
z Only contains Data lines /TXD and /RXD
z Serial Port 2 only used for transmitting AT command. It cannot be used for CSD call, FAX
call. And the Serial port 2 can not use multiplexing function;
zSerial port 2 supports the communication rate as following:
9600, 19200, 38400, 57600, 115200
Note: You should configure the serial port2 by AT command of “AT+UART” before you can use
serial port2. Please refer to the “SIM300 Dual Serial Ports User Guide” and document [1] for
detail.
SIM300_HD_V3.02 Page 30 of 56
SIM300 Hardware Interface Description
Confidential
SIMCOM
3.8.2 Software upgrade and Software debug
The TXD、RXD、DBGTX、DBGRX、GND must be connected to the IO connector when
user need to upgrade software and debug software, the TXD、RXD should be used for software
upgrade and the DBGTX、DBGRX for software debug. The PWRKEY pin is recommended to
connect to the IO connector. The user also can add a switch between the PWRKEY and the GND.
The PWRKEY should be connected to the GND when SIM300 is upgrading software. Please refer
to the following figures.
Figure 13: Interface of software upgrade
Figure 14: Interface of software debug
Note: The serial port doesn’t support the RS_232, it only supports the TTL level. You should add
the level converter IC between the DCE and DTE, if you connect it to the PC.
SIM300_HD_V3.02 Page 31 of 56
SIM300 Hardware Interface Description
Confidential
SIMCOM
3.9 Audio interfaces
Table 10: Audio interface signal
Name Pin Function
(AIN1/AOUT1)
(AIN2/AOUT2)
The module provides two Analogy input channels, AIN1 and AIN2, which may be used for both
microphone and line inputs. The AIN1 and AIN2 channels are identical. One of the two channels
is typically used with a microphone built into a handset. The other channel is typically used with
an external microphone or external line input. The Module Analogy input configuration is
determined by control register settings and established using Analogy multiplexes.
For each channels, you can use AT+CMIC to set the input gain level of microphone, use
AT+ECHO to set the parameters for echo suppression. Also, you can use AT+SIDET to set the
side-tone level. For detail, please refer to [1].
It is suggested that you adopt the one of following two matching circuits in order to satisfy speaker
effect。 The difference audio signals have to be layout according to difference signal layout rules.
As show in following Figures(Note : all components package are 0603) .If you want to adopt a
amplifier circuit for audio, we commend National company’s LM4890. But you can select it
according to your needs.
Mic1p 53 Microphone1 input +
Mic1n 55 Microphone1 input -
Spk1p 54 Audio1 output+
Spk1n 56 Audio1 output-
Mic2p 57 Microphone2 input +
Mic2n 59 Microphone2 input -
Spk2p 58 Audio2 output+
Spk2n 60 Audio2 output-
SIM300_HD_V3.02 Page 32 of 56
SIM300 Hardware Interface Description
Confidential
3.9.1 Speaker interface configuration
SIMCOM
Figure 15: Speaker interface configuration
Figure 16: Speaker interface with amplifier configuration
SIM300_HD_V3.02 Page 33 of 56
SIM300 Hardware Interface Description
Confidential
3.9.2 Microphone interfaces configuration
SIMCOM
Figure 17: Microphone interface configuration
3.9.3 Earphone interface configuration
Figure 18: Earphone interface configuration
SIM300_HD_V3.02 Page 34 of 56
SIM300 Hardware Interface Description
Confidential
3.9.4 Referenced Electronic Characteristic
SIMCOM
Table 11: MICInput DC Characteristics
Parameter Min Typ Max Unit
Work i ng Vol tage 1.25 2.5 V
Working Current 5 300 uA
External
Microphone
Load Resistance
1.2 2.2 k Ohms
Table 12: Audio Output Characteristics
Parameter MinTypMax Unit
Normal
Output(SPK1)
Auxiliary
Output(SPK2)
Ended
Differential
Ended
Differential
load
Resistance
Ref level 1.0954Vpp
load
Resistance
Ref level 0.5477Vpp
load
Resistance
Ref level 1.0954Vpp
load
Resistance
Ref level 0.5477Vpp
27 32 Ohm Single
27 32
27 32 Ohm Single
27 32
Table 13: Buzzer Output DC Characteristics
Parameter Min Typ Max Unit
Work i ng Vol tage 2.4 2.8 3.3 V
Working Current 8 mA
Load Resistance 1 k Ohms
3.10 Buzzer
The PIN 36 on the board-to-board connector can be used to drive a buzzer to indicate incoming
call. The output volume of buzzer can be set by “AT+CRSL”. The reference circuit for buzzer as
shown as following Figure:
SIM300_HD_V3.02 Page 35 of 56
SIM300 Hardware Interface Description
Confidential
SIMCOM
Figure 19: Reference circuit for Buzzer
3.11 SIM card interface
3.11.1 SIM card application
You can use AT Command to get information in SIM card. For more information, please refer to
[1].
The SIM interface supports the functionality of the GSM Phase 1 specification and also supports
the functionality of the new GSM Phase 2+ specification for FAST 64 kbps SIM (intended for use
with a SIM application Tool-kit).
Both 1.8V and 3.0V SIM Cards are supported.
The SIM interface is powered from an internal regulator in the module having nominal voltage
2.8V. All pins reset as outputs driving low. Logic levels are as described in table
SIM300_HD_V3.02 Page 36 of 56
SIM300 Hardware Interface Description
Confidential
Table 14: Signal of SIM interface (board-to-board connector)
Pin Signal Description
19 SIM_VDD SIM Card Power output automatic output on SIM mode,one is
21 SIM_I/O SIM Card data I/O
23 SIM_CLK SIM Card Clock
25 SIM_RST SIM Card Reset
16 SIM_PRESENCE SIM Card Presence
Following is the reference circuit about SIM interface. We recommend an Electro-Static discharge
device ST (
ANTI”. The 22Ω resistors showed in the following figure should be added in series on the IO line
between the module and the SIM card for matching the impedance. The pull up resistor (about
10KΩ) must be added on the SIM_I/O line. Note that the SIM peripheral circuit close to the SIM
card socket.
The SIM_PRESENCE pin is used for detecting the SIM card removal. You can use the AT
command “AT+CSDT” to set the SIMCARD configure. For detail of this AT command, please
refer to
You can select the 8 pins SIM card. The reference circuit about 8 pins SIM card illustrates as
following figure.
SIMCOM
3.0V±10%, another is 1.8V±10%. Current is about 10mA.
www.st.com ) ESDA6V1W5 or ON SEMI (www.onsemi.com ) SMF05C for “ESD