Ro (Packetization Timeout) Command; Rp (Rssi Pwm Timer) Command - Digi XTend User Manual

RO (Packetization Timeout) Command

<Serial Interfacing> The RO command is used to set/read the Packetization Timeout setting. RF transmission begins
when data is in the DI buffer and either of the following criteria are met:
•
RO character times of silence on the UART receive lines (after receiving at least 1 byte)
•
RB characters have been received by the UART
RB and RO criteria only apply to the first packet of a multi-packet transmission. If data remains in the DI Buffer (UART
receive) after the first packet, transmissions will continue in a streaming manner until there is no data left in the DI
Buffer.
When RO is the transmission-beginning criteria: The actual time between the reception of the last character from
the UART and the beginning of RF transmission will be at least 800 µsec longer than the actual RO time to allow for
transmission setup. Additionally, it is subject to 100-200 µsec of additional uncertainty, which could be significant for
small values of RO at high UART bit rates.
The correct UART character time (10, 11, or 12 bits) is calculated based on the following criteria:
•
1 start bit
•
8 data bits
•
0 or 1 parity bit [as determined by the NB (Parity) Command)
•
1 or 2 stop bits [as determined by SB (Stop Bits) Command]
AT Command: ATRO
Binary Command: 0x21 (33 decimal)
Parameter Range:0 - 0xFFFF [ x UART character times ]
Default Parameter Value: 3
Number of bytes returned: 2
Related Commands: RB (Packetization Threshold)

RP (RSSI PWM Timer) Command

<Diagnostics> RP Command is used to enable a PWM ("Pulse Width Modulation") output on the Config/RSSI pin (pin
11 of the OEM RF Module). The pin is calibrated to show the difference between received signal strength and the
sensitivity level of the RF module. PWM pulses vary from zero to 95 percent. Zero percent means the received RF
signal is at or below the published sensitivity level of the module.
AT Command: ATRP
Binary Command: 0x22 (34 decimal)
Parameter Range:0 - 0xFF [x 100 milliseconds]
Default Parameter Value: 0x20 (32d)
Number of bytes returned: 1
The following table shows dB levels above sensitivity and PWM values (The total time period of the PWM output is 8.32
ms. PWM output consists of 40 steps and therefore the minimum step size is 0.208 ms.):
XTend RF Module User Guide
Command descriptions
49