CC1101 Direct Mode getRSSI() only ever returns -74.0

[Crsarmv7l]

Describe the bug
When using Direct Mode with CC1101 and attempting to get the RSSI with getRSSI(), only -74.0 is ever returned, even when txing right next to the receiver.

Some output with basic debug, let me know if you want one of the other debugs enabled:

RLB_DBG: RadioLib Debug Info
RLB_DBG: Version:  6.5.0.0
RLB_DBG: Platform: ESP32
RLB_DBG: Compiled: Apr 24 2024 16:50:28

RLB_DBG: M	CC1101
CC1101 Init: Success!
-74.00
-74.00
-74.00
-74.00
-74.00
-74.00
-74.00
-74.00
-74.00
-74.00
-74.00
-74.00
-74.00
-74.00
-74.00

To Reproduce

#include <RadioLib.h>

CC1101 radio = new Module(6, 16, RADIOLIB_NC, 17);

const int pin = 17;


void IRAM_ATTR readBit(void) {
  // read the data bit
  radio.readBit(pin);
}


void setup() {
  Serial.begin(19200);
  while (!Serial) {};

  int state = radio.begin();
  if (state == RADIOLIB_ERR_NONE) {
    Serial.println(F("CC1101 Init: Success!"));
  }
  else {
    Serial.print(F("CC1101 Failed: Code "));
    Serial.println(state);
    while (true);
  }
  state = radio.setFrequency(433.92);
  if (!state == RADIOLIB_ERR_NONE) {
    Serial.print(F("Freq Failed, Code "));
    Serial.println(state);
    while (true);
  }
  state = radio.setBitRate(8.00);
  if (!state == RADIOLIB_ERR_NONE) {
    Serial.print(F("Datarate Failed, Code "));
    Serial.println(state);
    while (true);
  }
  state = radio.setOOK(true);
  if (!state == RADIOLIB_ERR_NONE) {
    Serial.print(F("Modulation Failed, Code "));
    Serial.println(state);
    while (true);
  }
  state = radio.setRxBandwidth(58);
  if (!state == RADIOLIB_ERR_NONE) {
    Serial.print(F("Bandwidth Failed, Code "));
    Serial.println(state);
    while (true);
  }
  state = radio.setPromiscuousMode(true, true);
  if (!state == RADIOLIB_ERR_NONE) {
    Serial.print(F("Promiscuous Failed, Code "));
    Serial.println(state);
    while (true);
  }
  state = radio.setDirectSyncWord(0, 0);
  if (!state == RADIOLIB_ERR_NONE) {
    Serial.print(F("Direct SyncWord Failed, Code "));
    Serial.println(state);
    while (true);
  }
  radio.setDirectAction(readBit);
  radio.receiveDirect();
}

void loop() {
  if (radio.available() >= 61) {
    Serial.println(radio.getRSSI());
    while (radio.available()) {
      byte b = radio.read();
    }
  }
}

Expected behavior
RSSI should vary.

Additional info (please complete):

• MCU: Adafruit Qt py ESP32-S2
• Wireless module type: CC1101
• Arduino IDE version: 1.8.19
• Library version: Latest

[jgromes]

Looks like the logic inside CC1101::getRSSI was inverted, returning the packet RSSI value in direct mode and the instantenous one in packet mode. Because you never received a packet in packet mode, the initial value was set to 0 from which offset of 74 dBm is subtracted, hence the -74 dBm return value.

I pushed a fix for this in the latest commit, thanks for reporting!

[Crsarmv7l]

Thanks!