AC4490 User Guide
Version 4.5
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Read Digital Inputs
The OEM Host issues this command to read the state of both digital input lines.
Command: <0xCC> <0x20>
Number of Bytes Returned: 2
Response: <0xCC> <Digital In>
Parameter Range:
<Digital In> = bit-0: GI0
bit-1: GI1
Read ADC
The OEM Host issues this command to read any of the three onboard 10-bit A/D converters. Because the RF is
still active in On-the-Fly Command Mode, the transceiver will not process the command until there is no
activity on the network. The Read RSSI command is therefore useful for detecting interfering sources but will
not report the RSSI from a remote transceiver on the network. The equations for converting these 10 bits into
analog values are as follows:
Analog Voltage = (10 bits / 0x3FF) * 3.3 V
Temperature (
o
C) = ((Analog Voltage - 0.3) / 0.01) - 30
Instantaneous RSSI value (dBm) = -105 + (0.22 * (0x3FF - 10 bits))
Command: <0xCC> <0x21> <Port>
Number of Bytes Returned: 3
Response: <0xCC> <Hi ADC> <Lo ADC>
Parameter Range:
<Port>
=
0x00: AD In
0x01: Temperature
0x02: Instantaneous RSSI
<Hi ADC> = MSB of requested 10-bit ADC value
<Lo ADC> =
LSB of requested 10-bit ADC value
Report Last Valid RSSI
Since RSSI values are only valid when the local transceiver is receiving an RF packet from a remote transceiver,
instantaneous RSSI can be tricky to use. Therefore, the transceiver stores the most recent valid RSSI value as
measured the last time the transceiver received a packet or beacon. The Host issues this command to retrieve
that value.
Note: This value will default to 0xFF on a client and 0x00 on a server if no valid RSSI measurement has
been made since power-up.
Command: <0xCC> <0x22>
Number of Bytes Returned: 2
Response: <0xCC> <Last Valid RSSI>
