Added firmware changes, updated the name of the removed old references to
LT2510 part numbers, added new information on cyclic sleep and Antenna
Switch Override. Added a table under Max Power and a table for the Set Max
Power command.
Minor grammatical fixes.
PWM output data was corrected to a 39.3846 µS period vs. 315.077, as was
stated previously.
Minor edits, removed Firmware History and references irrelevant to RM024.
Corrected Antenna Select Override information error. Changed 0x59 to 0x5B
Separated Hardware Integration Guide (HIG) from User Guide information
(created two separate documents).
Add Related Documents section.
Added information on FW v2.0, deprecated 50mW radio versions and added
10mW radio versions
2.2
2.3
2.4
2.5
3.0
27 June 2013
12 July 2013
10 Oct 2013
10 Dec 2013
3.1
13 Jan 2014
Americas: +1-800-492-2320 Option 2
Europe: +44-1628-858-940
Hong Kong: +852-2923-0610
www.lairdtech.com/ramp
2
CONN-GUIDE-RAMP24
RM024 User Guide
Version 3.1
C
ONTENTS
Revision History ............................................................................................................................................ 2
Key Features ........................................................................................................................................... 4
Theory of Operation .................................................................................................................................... 5
Adjustable RF Data Rate ............................................................................................................................. 5
Modes of Operation ................................................................................................................................... 6
Serial Interface Baud Rate........................................................................................................................... 7
Flow Control ........................................................................................................................................... 9
Radio Configurations ............................................................................................................................... 10
Configuring the RM024 ............................................................................................................................. 30
AT Commands ......................................................................................................................................... 30
Status Commands .................................................................................................................................... 34
Process to Manually Upgrade RM024 ....................................................................................................... 46
API Operation ............................................................................................................................................ 47
API Send Data Complete .......................................................................................................................... 47
API Receive Packet.................................................................................................................................... 47
API Transmit Packet .................................................................................................................................. 48
Related Documents and Files .................................................................................................................... 49
Americas: +1-800-492-2320 Option 2
Europe: +44-1628-858-940
Hong Kong: +852-2923-0610
www.lairdtech.com/ramp
3
CONN-GUIDE-RAMP24
RM024 User Guide
Version 3.1
RAMP M
ODULES
Laird RAMP (Range Amplified MultiPoint) modules are designed to provide robust wireless communications
for any number of applications requiring a wireless transport for serial data. RAMP modules feature a
Frequency Hopping Spread Spectrum (FHSS) protocol for excellent interference and multipath immunity.
RAMP modules server/client architecture allows for more than 16 million clients to be addressed and
communicating within the network.
Overview
The RM024 RAMP module is based on Laird LT2510 core technology, enhanced with a new RF front end for
improved sleep, improved link budget, and a switchable antenna output. The RM024 is available in two
versions, one with 125 mW maximum conducted output power which is approved for North American and
similar markets, and one with 10 mW maximum conducted output power which is approved for European
and similar markets. These modules are identical except for output power, transmit power consumption, and
the number of RF channels available. Differences between the two versions, where applicable, are denoted
based on part number.
This document contains information about the hardware and software interface between a Laird RM024
transceiver and an OEM host. Information includes the theory of operation, specifications, interface
definitions, and mechanical drawings.
Note:
Unless mentioned specifically by name, the RM024 modules are referred to as “radio” or
“transceiver”. Individual naming is used to differentiate product specific features. The host
(PC/microcontroller/any device to which the RM024 module is connected) are referred to as “OEM
host” or “host.”
Key Features
Forward Error Correction option for longer range
Retries and acknowledgements
Configurable network parameters
Multiple generic I/O
280 kbps or 500 kbps RF data stream
Idle current draw of 9.5 mA, sleep current of 38 uA
Software selectable interface baud rates from 1200 bps to 460.8 kbps
Upgradable FW through serial port
Low cost, low power, and small size ideal for high volume, portable, and battery powered applications
All modules are qualified for Industrial temperatures (-40°C to 85°C)
Advanced configuration available using AT commands
Easy to use Configuration and Test Utility software
Switchable antenna output, either integrated antenna or external antenna through U.FL
Americas: +1-800-492-2320 Option 2
Europe: +44-1628-858-940
Hong Kong: +852-2923-0610
www.lairdtech.com/ramp
4
CONN-GUIDE-RAMP24
RM024 User Guide
Version 3.1
T
HEORY OF
O
PERATION
Server/Client Architecture
The RM024 utilizes server-client network architecture to synchronize the frequency hopping. Each network
must have one radio configured as a server and all other radios configured as clients. When a radio is
configured as a server, it transmits a beacon containing timing and identification information at the
beginning of each hop. The beacon is never visible to the OEM host. Upon boot, radios configured as clients
enter receive mode where they are scanning the available frequencies listening for a beacon from a server in
their network. When a client detects the server’s beacon, the client synchronizes its frequency hopping to
that of the server and transition the In Range pin Low. When the server and the client are synchronized they
can begin transferring data.
Each network consists of only one server. Multiple networks can exist in the same area, provided the
networks are configured on different channels. The RM024 utilizes an intelligent Frequency Hopping
algorithm which ensures minimal interference between networks. The possible interference between
collocated networks is given by the following equation:
Maximum number of interfering bins = # of collocated servers -1
For example, with ten collocated networks, there is up to nine bins every hop cycle that are occupied by more
than one network at the same time. Although two or more networks might occupy the same hop bin at the
same time, there is truly only interference if two or more radios from alternate networks are trying to
transmit on the same bin at the same time in the same coverage area.
Adjustable RF Data Rate
The RM024’s RF data rate can be adjusted to provide a trade-off between throughput and range.
Table 1: RM024 RF Data Rate
Product Model
All RM024
125 mW versions
(RM024-X125) only
RF Profile
0x00
0x01
RF Data Rate
500 kbps
280 kbps
Number of Hops
43
79
Receiver Sensitivity
-94 dBm
-95 dBm
Throughput
1
250 kbps
120 kbps
All RM024
0x03
280 kbps
43
-95 dBm
120 kbps
1. Throughput is ideal, one direction, with no retransmissions. All practical RF applications should allow
for retransmission of data due to interference or less than ideal RF conditions.
Deciding which RF data rate to choose depends on the individual application. The fast RF data rate delivers
much faster throughput, but has much less range. In addition, because the lower data rate solution uses
more hops, it is better situated for collocated networks.
A rule of thumb for RF systems is every six dB of gain doubles the effective distance. The four dB increase of
receive sensitivity for the lower data rate solution means it is able to transmit almost 60% further than the
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