RM024 – RAMP Wireless Module

Datasheet

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Figure 2: RF hop frame diagram

2.1 Pin Descriptions

2.1.1 RXD and TXD

The RM024 accepts 3.3 VDC TTL level asynchronous serial data from the OEM host via the RXD pin. Data is sent

from the transceiver, at 3.3 volt levels, to the OEM host via the TXD pin. Pins should be left floating or high when

not in use. Leaving the RXD tied low results in the radio transmitting garbage serial data across the RF.

2.1.2

Force 9600 /Sleep Interrupt

When pulled logic Low before applying power or resetting, the transceiver’s serial interface is forced to 9600,

8-N-1 (8 data bits, no parity, 1 stop bit) regardless of the actual EEPROM setting. RTS is ignored, the interface

timeout is also set to three milliseconds, and the RF packet size is set to the default size for the selected RF data

rate. To exit, the transceiver must be reset or power-cycled with the test pin logic High or disconnected. When

in Force 9600 mode, the radio’s receiver is disabled.

When enabled in the EEPROM, the 9600 Boot option causes the 9600 pin to be ignored on cold boot (power-up),

command boot (0xCC 0xFF), and brown-out conditions. Therefore, the 9600 pin is only observed on warm boots

(reset pin toggled). This can be helpful so that brown-out conditions don’t cause the baud rate to change if the

9600 pin happens to be low at the time. When 9600 Boot option is disabled, the 9600 pin is used for all boot

conditions. 9600 Boot option is enabled by default.

Force 9600 is also used to wake the radio from sleep. When the pin is taken low, the radio wakes. The

transceiver does not sleep if the pin is low when the sleep command is issued.

Note: Because this pin disables some modes of operation, it should not be permanently pulled Low during

normal operation.