Adeunis RF ARF868 ULR Mode D'emploi page 43

ARF868 Radio Modems - User guide version V1.6
toring equipment is set to: 8bits, 1 stop bit, no parity and that the UART proposed corresponds with one of the data rates available in register
S210.
Sending of the synchronisation character "U" is only useful on first switching on or as long as a UART configuration has not been memorised on
registers S210 by the AT&W command.
On equipment that is already synchronised, it will not be interpreted as a synchronisation request and will be transferred onto the air link like
any other character chain.
The self-detection mode (type & data rate) will be retained for the next switching on in the following three situations:
• No saving of register S210 by the AT&W command before switching off.
• Brief pressure on BP1 before the power is cut off
• Return of register S210 to the value of 0 by ATR and AT&W commands before the power is cut off.
4.3. RSSI
The Received Signal Strength Indication or RSSI provides an indication of the RF level in the selected audio channel.
Depending on the value observed, it indicates the availability of the channel and the noise level in the product's environment, or the quality of
reception of the frames from a distant product. The terminals are -127dBm for the lower limit and -20dBm for the upper limit
The RSSI is deactivated (by default) by positioning register S230 at: 0
4.3.1 RSSI continu
The RSSI is coded on one octet in absolute values of the channel level value in dBm and transmitted to the UART. The RSSI is refreshed conti-
nuously every 10 ms. There is no frame demodulation in this mode.
Register settings and values
Selection of the continuous RSSI mode is done by register S230, by setting the value to: 4
4.3.2 Frame RSSI
The frame RSSI is the code on one octet at the beginning of each frame transmitted on the UART. The encoding is identical to the continuous
RSSI.
Register settings and values
Selection of the continuous RSSI mode is done by register S230, by setting the value to: 1
4.4. Scan Free function
The Scan Free function is a function that is unique to ARF868 modems.
This function enables sweeping of all channels available on the product in a few seconds. It is activated by the ATT02 command.
The ARF868 modem scans all the channels available and returns the RSSI levels on each of the channels to the UART link in the following form: :
Cxxx=-090dBm<cr><lf> ; with xxx = channel no
Cyyy=-101dBm<cr><lf> ; with yyy = No of the following channel
......
The polling time of a channel is defined as 25ms. The result of this polling may show that some channels are more usable than others in a given
environment.
As a second stage and for a more reliable assessment, we can use the ATT03 command which enables the channel to be listened to over a
longer period:
ATT03<c (channel)><t (polling time)>
With : <c> = Channel no
With: <t> = Polling time in seconds
E.g.: ATT03 529 60 -> Scan of channel 529 for 1 minute. The result returned has the following form:
C529=-087/-096/-101dBm<cr><lf>; i.e. in order: RSSI min. RSSI mean/RSSI max. measured over this period.
4.5. Transmission/reception test
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