[87] RADIO: RSSI parameter adjustment

This anomaly applies to IC Rev. Rev 1, build codes QKAA-D00.

It was inherited from the previous IC revision Engineering D.

Domains

Network

Symptoms

RSSI varies with temperature and input power level.

Conditions

Always.

Consequences

RSSI parameter is not within specified accuracy.

Workaround

Add the following compensation to the RSSI sample value based on temperature measurement and RSSISAMPLE. The on-chip TEMP peripheral can be used to measure temperature.

compensated_rssi = (uint8_t)round(
    (float)((float)(1.56f * rssi_sample) + (float)(4.9e-5 * pow(rssi_sample, 3)) -
    (float)(9.9e-3 * pow(rssi_sample, 2)) - (0.05f * ((float)(temp)*0.25f)) - 7.2f));
where
temp
Temperature sample value as reported by register NRF_TEMP.TEMP in increments of 0.25.
drssi_sample
Sample value as reported by register NRF_RADIO.RSSISAMPLE.