AP_RCProtocol: CRSF: use subtraction with times, not time+timedelta

peterbarker · tridge · commit b19f8ed57f65 · 2024-02-22T20:46:40.000+11:00
diff --git a/libraries/AP_RCProtocol/AP_RCProtocol_CRSF.h b/libraries/AP_RCProtocol/AP_RCProtocol_CRSF.h
@@ -58,13 +58,13 @@ class AP_RCProtocol_CRSF : public AP_RCProtocol_Backend {
     bool is_rx_active() const override {
         // later versions of CRSFv3 will send link rate frames every 200ms
         // but only before an initial failsafe
-        return AP_HAL::micros() < _last_rx_frame_time_us + CRSF_RX_TIMEOUT;
+        return _last_rx_frame_time_us != 0 && AP_HAL::micros() - _last_rx_frame_time_us < CRSF_RX_TIMEOUT;
     }
 
     // is the transmitter active, used to adjust telemetry data
     bool is_tx_active() const {
         // this is the same as the Copter failsafe timeout
-        return AP_HAL::micros() < _last_tx_frame_time_us + CRSF_TX_TIMEOUT;
+        return _last_tx_frame_time_us != 0 && AP_HAL::micros() - _last_tx_frame_time_us < CRSF_TX_TIMEOUT;
     }
 
     // get singleton instance

Original file line number	Diff line number	Diff line change
`@@ -58,13 +58,13 @@ class AP_RCProtocol_CRSF : public AP_RCProtocol_Backend {`
`58`	`58`	`bool is_rx_active() const override {`
`59`	`59`	`// later versions of CRSFv3 will send link rate frames every 200ms`
`60`	`60`	`// but only before an initial failsafe`
`61`		`- return AP_HAL::micros() < _last_rx_frame_time_us + CRSF_RX_TIMEOUT;`
	`61`	`+ return _last_rx_frame_time_us != 0 && AP_HAL::micros() - _last_rx_frame_time_us < CRSF_RX_TIMEOUT;`
`62`	`62`	`}`
`63`	`63`
`64`	`64`	`// is the transmitter active, used to adjust telemetry data`
`65`	`65`	`bool is_tx_active() const {`
`66`	`66`	`// this is the same as the Copter failsafe timeout`
`67`		`- return AP_HAL::micros() < _last_tx_frame_time_us + CRSF_TX_TIMEOUT;`
	`67`	`+ return _last_tx_frame_time_us != 0 && AP_HAL::micros() - _last_tx_frame_time_us < CRSF_TX_TIMEOUT;`
`68`	`68`	`}`
`69`	`69`
`70`	`70`	`// get singleton instance`