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 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 Comma
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.
. 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.
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.
Functional Description of the Serial Interface Signals PIN 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Name Definition *P_RXD – Program Receive Data – Input pin for uploading flash code into CC1010 * *PROG – Program – Input pin to activate flash program * 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.
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.
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.
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 To demonstrate a simple point-to-point connection, with both modules in their default state, send the “ ATD” command followed by a (carriage return or Enter Key) on one module and then send the “ ATA” command followed by a to the other module. The “ ATD” command instructs the module to attempt to establish a wireless data link in the Originate Mode. The “ ATA” command instructs the other module to attempt to establish a wireless data link in the Answer mode.
Auto Link Operation Setting and storing the modules Auto Link settings into the modules Non Volatile Memory (NVRAM) allows the pre-configuring of the modules DTE speed, data link speed, transmit levels, frequency of operation, and channel Ids for establishing a constant wireless data link. Once these parameters are stored, the module will be conditioned to automatically maintain a connection.
Point to Multi-point Operation In this mode, a Master module will broadcast or transmit data to all available Slave modules operating on the same frequency. All Slaves will receive data from the Master and the host software will determine which of the Slaves transmit data back to the Master. It is invalid for more than one Slave to respond at the same time. The Master will only receive data that is transmitted by the Slave. Slave-to-Slave operation is not possible.
Suggestions for Improving the Connection Optimum performance between two WHM900 modules will vary depending on the proximity of the two modules and the type of antenna used. Try adjusting the antenna for best reception. Start by positioning the antenna straight up and adjust as necessary. Pointing the antenna towards the other module will not improve the reception. Do not place the antenna next to large pieces of metal because it will cause additional interference.
4) Toggling the DTR signal (Pin #6) from On to Off can be used to put the module in either the On Line Command Mode or Off Line Command Mode. If AT&D1 is set and the DTR signal is turned off, the module will enter the On Line Command Mode and will require an ATO to return on line or an ATH to disconnect. If AT&D2 is set and DTR is turned off, the module will enter the Off Line Command Mode.
AT Command Listing This section will list the basic commands required for most applications. Some commands have parameters associated with them. The format is as follows: AT&Dn where “ n” equals the parameter, usually 0 or 1. If a command with a parameter (n) is issued without the (n), the module will assume that n = 0. For example issuing AT&D would equivalent to AT&D0. The following lists the available AT commands. AT Commands A/ Repeat previous command.
%An Transmit Level. This command will set the modules transmit level. Use the chart below to set the modules transmit level. The default is 0dBm. Issuing AT%A160 will set the module transmit level to 0dBm. The FCC has placed transmit level limits on particular frequencies. In those cases the %Fn (Set Frequency Command) will override and limit the %An Transmit setting.
&Cn Mode Indicator - The Mode Indicate Pin (3) reflects whether the module is In Data Mode or Command Mode. A Low output indicates the module is in connected (Data Mode). If this output is High, the module is ready to receive commands (Command Mode). The MI signal can be forced with the AT&Cn command. &C0 Mode Indicate signal is forced high. &C1 Mode Indicate signal will indicate whether the module is in On Line Data Mode or Off Line Command Mode (default).
En Command Echo. The ATEn command determines whether the AT command string will be echoed back to the Host DTE when issued. E0 E1 &F Disables command echo. Enables command echo (default). Restore factory configuration (profile). The AT&F command will reset all commands and registers to their factory default values. Any changes to the module settings will be lost when the AT&F command is issued unless they were previously saved into the module memory with the AT&W command.
H Exit RF Link – This command can be used to end an RF wireless On Line session. The ATH command can only be used if the module is placed in the On Line Command Mode by entering the “ +++” escape mode sequence. See “ Changing from Data mode to Command Mode” for more information on using this command. I4 Firmware Identification - This command will display the modules current firmware version. Example: 09/27/2004-001 Wireless V 1.
Mn Auto Pole – This command enables the module to automatically search for any available IDs or Frequencies. Select ATM2 for an ID search or ATM3 for a frequency search. For Point-to-Point search operation issue the ATD command. For Auto Link search operation issue the ATS0=2 command. If the module finds a valid ID (M2) or frequency (M3), the two modules will automatically connect and display the appropriate connect result codes.
O Return to Data Mode - The ATO command is used to exit the On Line Command Mode and return to the On Line Data Mode. When this command is entered the module will respond with the appropriate CONNECT result code. This command is invalid if frequency hopping is enabled. See Changing from Data Mode To Command Mode for more information on the ATO command. Qn Quiet results codes control – Each time an “ AT” command is issued, the module will respond with a response or result code.
%Sn Select Channel ID – Use this command to choose one of the available 256 Channel IDs that you want to use to communicate. To communicate with one of more remote modules, they must all use the same unique Channel Id Number. The channel range is between 0 and 255. The default is Channel 255.
\Vn Extended Result Code – This command defines the attributes of the CONNECT result code. \V0 Connect result code will be appended with the DTE (Serial Port Host Interface) Speed. For example “ CONNECT 9600” indicates the Serial Interface is 9600bps. \V1 Connect result code will reflect the RF data link speed. For example “ CONNECT RF9600” indicates that the RF data link is at 9600.
AT S Registers This section lists the basic AT Command Set S registers. The S registers use the following format: ATSr=n where “ r” is the S register number and “ n” is the value or parameter to set it to. To read the current contents of an S Register, issue ATSr? where “ r” is the register in question. The module will then display the value of the S Register. Register Range Units Default Description______________________________ This register serves several functions.
Command Result Codes The module will issue result codes in response to processing an AT command. The ATQn command controls if result codes are issued (ATQ0) or not issued (ATQ1). The En command determines if the result codes and commands are echoed. Connect result codes are controlled by the AT\Vn command. The ATVn will select numeric or verbose result codes.
Receiver Sensitivity The following reflects the RF Data Rate and corresponding Receive Sensitivity with frequency separation fixed at 64Khz intervals and the module is operating at 915 MHz. RF Data Rate 600bps 1200bps 2400bps 4800bps Sensitivity (Manchester Mode) -110dBm -108dBm -106dBm -103dBm RF Data Rate 9600bps 19.2Kbps 38.4Kbps 76.
To communicate with the module test fixture you must first set-up your terminal or PC. Make sure you select the appropriate communication serial port. For most applications, select 8 DATA bits, No Parity bit, 1 STOP bit, and Hardware Flow Control. If you are using a terminal program, you may find these options under communication settings or terminal settings. Some software packages require that you select a specific brand or type of modem. You may select Hayes compatible, Standard or Default.
RS232 EIA Serial Port Cable Information The RS232 EIA Serial Port cable contains 25 pins through which the terminal or PC can communicate to the MDK2001. The following table will describe the connections.
4 - Attach one end of the parallel cable to the 25pin connector on the right side of the MDK2001. Connect the other end to the parallel port of the PC. 5 – Place the power switch located at the rear of the MDK2001 in the OFF (down) position. Connect the power jack of the MDK power supply into the power receptacle next to the power switch. Insert the power adapter into any available 110 VAC outlet. Turn the power switch into the ON (up) position. The RI/WIP, CTS, and PWR lights should be illuminated.
Limited Warranty Warranty Coverage and Duration Radicom Research, Inc. (“ RRI” ) warrants to the original purchaser its RRI-manufactured products (“ Product” ) against defects in material and workmanship under normal use and service for a period of one year from the date of delivery. During the applicable warranty period, at no charge, RRI will, at its option, either repair, replace or refund the purchase price of this Product, provided it is returned in accordance with the terms of this warranty to RRI.
(d) Disassembly or repair of the Product in such a manner as to adversely affect performance or prevent adequate inspection and testing to verify any warranty claim. (e) Any Product that has had its serial number or date code removed or made illegible. How to Receive Warranty Service: To obtain warranty service, contact RRI by phone (408)383 9006 for RMA Department or email to rma@radi.com for an RMA (Return Merchandise Authorization) number.
Contacting Radicom Research If more information or technical support is needed, please contact us: Radicom Research, Inc. 2148 Bering Drive San Jose, CA. 95131 Telephone: (408) 383 9006 Fax: (408) 383 9007 Or e-mail: sales@radi.com http://www.radi.
