Radicom Research WHM900 Users Manual
Radicom Research, Inc.
Development Guide
For the
WHM900
Wireless Half Inch Radio Frequency
Module
Revision: July 8, 2005 Preliminary
Information furnished by Radicom Research is believed to be accurate and reliable. However
Radicom Research assumes no responsibility for its use, or any infringement of patents or other
rights of third parties that may result from its use. Radicom Research reserves the right to
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change circuitry at any time without notice. This document is subject to change without notice.
Table of Contents
Introduction 3
General Specifications 4
Mechanical Specification and Pin Orientation 5
Serial TTL Interface Signal Level Pin Assignments 6
Functional Description of the Serial Interface Signals 7
Antenna Connection 8
FCC Compliance 8
Wireless Data Link Options 10
Point to Point Operation 11
Auto Link Operation 12
Point to Multi-point Operation 13
Suggestions for Improving the Connection 14
Changing from Data Mode to Command Mode 14
The AT Command Set 15
AT Command Listing 16
AT S Registers 25
Command Result Codes 26
Receiver Sensitivity 27
MDK-2001 Development Board 27
MDK-2001 Lights and Description 28
RS232 EIA Serial Port Cable Information 29
Uploading New WHM900 Code 29
Limited Warranty 31
Contacting Radicom Research 33
2
Introduction
The WHM900 RF Module is designed to provide designers a hardware solution for
integrating RF wireless data communication applications into different types of
embedded host systems or remote equipment. The WHM900 requires only a serial 3.3 V
TTL interface and antenna to provide wire-less data communications for these systems.
The designer will be required to implement the necessary hardware to host the WHM900
as well as write the software to control the modules wireless link by using the popular AT
command set. The WHM900 is designed to communicate using Radio Frequencies in the
license free ISM bandwidth (900 – 928 MHz). The wireless link operates at speeds up to
76.8Kbps and will reach distances up to 1000 feet depending on the environment and
operational mode. The modules provide 32 user selectable frequencies with 256 different
channel IDs. Frequency hopping with 50 channels and adjustable transmit levels are also
featured. Data error correction and flow control functions are standard. The modules can
be used for point-to-point, point-to-multi-point, or multiple point-to-point wireless
operation. The WHM900 can also be configured to automatically connect and maintain a
continuous wireless using the modules Auto Link option. This document provides all of
the information integrators need to incorporate the Radicom WHM900 RF Module into
their system for state of the art wireless data communication.
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General Specifications
.
Radio Frequency: 900 – 928 MHz (License-Free ISM Band)
Range: Up to 1000 feet
Channels: 256 Different User Selectable Channels
Full RF Range Frequency Hopping or 32 User Selectable Frequency Settings
RF Data Rates (bps): 1200, 2400, 4800, 9600, 19.2K, 38.4K, 76.8K
Transmit Levels: AT Command Selectable Range – Max: 0dBm to Min: –20dBm
Modulation Scheme: Frequency Shift Keying (FSK)
Coding: Manchester Mode
Receiver Sensitivity: Data Rate and RF Frequency dependent
Built in Error Correction
Supports Hardware (RTS/CTS) and Software (XON/XOFF) Flow Control
AT Command Data Format: Asynchronous 10 Bit – 1 Start, 8 Data No Parity, 1 Stop
Terminal Data Rate in bits per second (DTE): 300, 1200, 2400, 9600, 19.2K, 57.6K
Terminal Data Rate Tolerance: Over-speed / Under-speed + / - 1%
Interface: Serial TTL compatible I/O (3.3volts)
Voltage Range: 3.0V- 6.0V operation
Uses Popular “AT” command set for easy software configuration
Includes on board NVRAM for storing configuration into memory
Power Consumption: Transmit Mode: 36mA typical
Receive Mode: 28mA typical
Idle Mode (off line) 16mA typical
Low Power Down Mode 4mA typical
Antenna Type: ¼ wave omni-directional with Reverse Polarity SMA Plug (Male)
Antenna Gain: Maximum 2dBi
Input Impedance: 50 ~ Nominal
Physical Dimensions: 1.0(W) x 1.0(L) x 0.3(H) in.
Weight: 0.3oz. or 7g
Operating Temperature: -40C to +85C
FCC: Complies with FCC CFR47 Part 15.247 and 15.249
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Mechanical Specification and Pin Orientation
5
Serial TTL Interface Signal Level Pin Assignments
The WHM900¹ is designed for easy connection to any standard serial 3.3V TTL
interface. The connection is made through two 10pin headers.
Serial TTL Interface Signal Level Definition:
PIN Number Name Type Comments
1 P_RXD Input Vih: 2.31V ~ 3.6V
Vil: 0V ~ 0.99V
2 PROG Input Vih: 2.31V ~ 3.6V
Vil: 0V ~ 0.99V
3 MI Output Voh: 2.5V ~3.3V
Vol: 0 ~ 0.4V
4 CTS Output Voh: 2.5V ~3.3V
Vol: 0 ~ 0.4V
5 LIP Output Voh: 2.5V ~3.3V
Vol: 0 ~ 0.4V
6 DTR Input Vih: 2.31V ~ 3.6V
Vil: 0V ~ 0.99V
7 RTS Input Vih: 2.31V ~ 3.6V
Vil: 0V ~ 0.99V
8 TXD Input Vih: 2.31V ~ 3.6V
Vil: 0V ~ 0.99V
9 RXD Output Voh: 2.5V ~3.3V
Vol: 0 V~ 0.4V
10 GND ----
11 P_CLK Input Vih: 2.31V ~ 3.6V
Vil: 0V ~ 0.99V
12 P_TXD Output Voh: 2.5V ~3.3V
Vol: 0V~ 0.4V
13 TXD2 Output Voh: 2.5V ~3.3V
Vol: 0V ~ 0.4V
14 RXD2 Input Vih: 2.31V ~ 3.6V
Vil: 0V ~ 0.99V
15 GND ----
16 RST Input
17 VCC Power Vih: 6.0V
Vil: 3.0V
18 N/C Pin has been
removed
19 ---- Not Used
20 ---- Not Used
KEYED
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Functional Description of the Serial Interface Signals
PIN Name Definition
1 *P_RXD – Program Receive Data – Input pin for uploading flash code into
CC1010 *
2 *PROG – Program – Input pin to activate flash program *
3 MI – Mode Indicator – Low output indicates the module is in Data Mode. If this
output is High, the module is ready to receive commands (Off Line Command
Mode). This signal can also be forced with the AT&C1 command. Note: The MI
signal will always be low when AT\I1 polling is enabled.
4 CTS – Clear to Send – Low output signal from the module telling the DTE, that
it’s OK to send data. The CTS and RTS signals work in conjunction to control the
flow of data in the event of a full data buffer. CTS will always be low unless the
module is in a flow control situation.
5 LIP - Link in Process – Low output indicates that the module is attempting to
establish a link with another module. It also will reflect when data retransmission
is occurring. This signal will constantly toggle during a Frequency Hopping Link.
This LIP signal is disabled when Polling is enabled (See AT\I command)
6 DTR – Data Terminal Ready – A low signal indicates the module is in data mode
and is ready to go online. This signal must be provided to establish a data link.
This signal can also be forced with the AT&D0 command. If connected to a
remote WHM900 and the DTR signal goes high, the module will stop data
communications and go into command mode. If the DTR signal is not used it
should be pulled down to ground.
7 RTS – Request to Send – Low input signal from the DTE to ask if the module is
ready to send data. This signal is used to flow off and on data when the module
buffers are full. RTS works in conjunction with the CTS output signal from the
module. If the RTS signal is not used, it should be pulled down to ground.
8 TXD – Transmit Data – Used for transmitting data from the DTE.
9 RXD – Receive Data – Used for received data path.
10 GND – Ground
11 *P_CLK – Program Clock – Input clock signal for programming flash*
12 *P_TXD- Program Transmit Data – Output for flash programming*
13 *TXD2 – Transmit Debug – Output transmit data for debugging purposes*
14 *RXD2 – Receive Debug – Input receive data for debugging purposes*
15 GND – Ground
16 RST—Module Reset –A 50ms low input will reset the module.
Wait 3 seconds after resetting before issuing commands to the module.
This signal is not required and can be left floating if not used.
17 VCC – Voltage – 3.0 – 6.0 volt input
18 No Pin – Should be Keyed to prevent accidentally plugging module in backwards
19 Not Used – No Connection- Can be used for mounting purposes
20 Not Used – No Connection- Can be used for mounting purposes
* Note: These pins are proprietary and are not required for normal wireless
communication. These pins should be considered not used and have no electrical
signals connected to them.
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Antenna and Cable Connections
The FCC Part 15 approved WHM900 RF Module comes equipped with a Reverse
Polarity SMA Female Jack for connection to a Reverse Polarity SMA Male plug antenna.
The WHM900 can be purchased with a ¼ Wave Omni-Directional Antenna with 2dBi
gain. The integrator may use other manufacturers antennas providing they are ¼ wave
Omni-Directional type with a gain of 2dBi or lower and meet the FCC Part 15 Antenna
Information listed in the FCC Compliance section of this manual. Note that a Reverse
Polarity SMA Antenna meets the FCC requirement for an antenna connection. A cable
may be added between the WHM900 and the antenna providing it meets the same
connection requirements as the antenna and providing that the finished product still
passes the FCC Part 15 Emissions Requirements.
FCC Compliance
The WHM900 module is designed for integration into a finished product. The WHM900
module is certified to meet the sections 247 and 249 of Part 15 of the FCC Rules. The
finished product containing the module must meet all other testing, labeling, and user’s
information requirements per Part 15 of the FCC rules.
FCC Antenna Information – Per FCC Part 15 rules, no antenna type other than that
furnished or approved by the responsible party (integrator or designer) shall be used with
the device. The use of a permanently attached antenna or an antenna that uses a unique
coupling to the device shall be considered sufficient. The manufacturer may design the
device so that a broken antenna is replaceable by the end user providing that a standard
antenna jack or electrical connector is not used. Refer to the FCC Part 15 Rules and
Regulations for more information.
WARNING: Using an antenna other then the type approved for
use with this product requires the finished product, with the
WHM900 module and new antenna type installed to be tested to
comply with all sections of FCC Part 15 requirements!
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The enclosed device complies with Part 15 of the FCC Rules. Operation is subject to
the following two conditions: (1) this device may not cause harmful interference and
FCC Part 15 User Information – The manual or installation guide for the finished
product must contain the following information:
This equipment has been tested and found to comply with the limits for a Class B digital
device, pursuant to part 15 of the FCC Rules. These limits are designed to provide
reasonable protection against harmful interference in a residential installation. This
equipment generates, uses and can radiate radio frequency energy and, if not installed and
used in accordance with the instructions, may cause harmful interference to radio
communications. However, there is no guarantee that interference will not occur in a
particular installation. If this equipment does cause harmful interference to radio or
television reception, which can be determined by turning the equipment off and on, the
user is encouraged to try to correct the interference by one or more of the following:
Reorient or relocate the receiving antenna.
Increase the separation between the equipment and receiver.
Consult the dealer or an experienced radio/TV technician for help.
Connect the equipment into an outlet on a circuit different from that to which the
receiver is connected.
Changes or modifications not expressly approved by the party responsible for
compliance could void the user’s authority to operate the equipment!
RF EXPOSURE WARNING - The FCC has developed guidelines to reduce any
possible hazard due to exposure of the human body to electromagnetic radiation The
antenna installation must provide a separation distance of 20cm (8") between the antenna
and all persons.”
FCC Part 15 Labeling Information - When the module is installed in a finished
product with no antenna modifications, the finished product must be labeled with the
following:
The above labeling information may be added to the finished product’s label or can be on
a separate label. The finished product’s label must have it’s own FCC ID (XXX-XXXX)
and the following information.
FCC ID: XXX-XXXXX
(2) this device must accept any interference received, including interference that
may cause undesired operation. Contains FCC ID: K7T-WHM900
Contains FCC ID: K7T-WHM900
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Wireless Data Link Options
The WHM900 is capable of establishing different types of wireless data links. The three
most common methods are described below. Review these choices to determine which
best fits your application. The mode of operation is determined by issuing specific “AT”
commands to the module. These “AT” commands are also used to select the speed,
frequencies, transmit levels and many other features the WHM900 RF module offers.
Point-to-Point Operation - This method allows the user to set-up single or multiple pointto-point locations by setting different channel IDs, frequencies, and speeds. This method
requires writing software to communicate to each module individually and determine
when to enter the online mode by issuing specific “AT” commands to the module.
Checking the modules I/O signals or result codes can monitor the current status of each
location.
Auto Link Operation - This feature forces the two modules to automatically maintain a
point-to-point connection. If a power outage were to occur or if the link was lost due to
temporary interference, the modules will detect the lost data link and automatically
establish a new wireless data link.
Point to Multi-Point Broadcasting – This mode allows for a Master module to broadcast
data to multiple remote Slave modules. The host software will control all data flow
between the masters and slaves. This method is sometimes referred to as Polling.
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