R308 AT Command Manual - wless.ru
R308 AT Command Manual - wless.ru
R308 AT Command Manual - wless.ru
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<strong>R308</strong> <strong>AT</strong> <strong>Command</strong>s<br />
8.2 Interpreting RSSI Energy Levels<br />
On the ETRX2 and ETRX3 series modules the readings from <strong>AT</strong>+ESCAN represent the<br />
hexadecimal readings from the RSSI register of the EM250 or EM35x, offset by +127 to make it a<br />
positive number. <strong>AT</strong>+ESCAN returns the background radio power so that the quietest channel can<br />
be selected for a new network; if you want to measure the RSSI of incoming messages you must<br />
set bit C of register S10 (see page 65).<br />
The EM250 and EM35x SoCs calculate the RSSI over an 8-symbol period as well as at the end of<br />
a received packet. They utilize the RX gain settings and the output level of the ADC within its<br />
algorithm. The linear range of RSSI is specified to be 40dB over all temperatures. At room<br />
temperature, the linear range is approximately 60dB (-90 dBm to -30dBm).<br />
©2012 Telegesis (UK) Ltd - 105 - <strong>AT</strong> <strong>Command</strong> <strong>Manual</strong> (Rev 3.08)
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