Softserial can now be enabled/disabled via the SOFTSERIAL feature switch in the command line. Softserial baud rate can be set via softserial_baudrate setting. Added input & output inversion support, use softserial_inverted setting.

src/board.h

@@ -74,6 +74,7 @@ typedef enum {
     FEATURE_POWERMETER = 1 << 12,
     FEATURE_VARIO = 1 << 13,
     FEATURE_3D = 1 << 14,
+    FEATURE_SOFTSERIAL = 1 << 15,
 } AvailableFeatures;
 
 typedef enum {

src/cli.c

@@ -44,7 +44,7 @@ static const char * const mixerNames[] = {
 static const char * const featureNames[] = {
     "PPM", "VBAT", "INFLIGHT_ACC_CAL", "SERIALRX", "MOTOR_STOP",
     "SERVO_TILT", "GYRO_SMOOTHING", "LED_RING", "GPS",
-    "FAILSAFE", "SONAR", "TELEMETRY", "POWERMETER", "VARIO", "3D",
+    "FAILSAFE", "SONAR", "TELEMETRY", "POWERMETER", "VARIO", "3D", "SOFTSERIAL",
     NULL
 };
 
@@ -115,6 +115,8 @@ const clivalue_t valueTable[] = {
     { "servo_pwm_rate", VAR_UINT16, &mcfg.servo_pwm_rate, 50, 498 },
     { "retarded_arm", VAR_UINT8, &mcfg.retarded_arm, 0, 1 },
     { "serial_baudrate", VAR_UINT32, &mcfg.serial_baudrate, 1200, 115200 },
+    { "softserial_baudrate", VAR_UINT32, &mcfg.softserial_baudrate, 9600, 19200 },
+    { "softserial_inverted", VAR_UINT8, &mcfg.softserial_inverted, 0, 1 },
     { "gps_baudrate", VAR_UINT32, &mcfg.gps_baudrate, 1200, 115200 },
     { "serialrx_type", VAR_UINT8, &mcfg.serialrx_type, 0, 2 },
     { "vbatscale", VAR_UINT8, &mcfg.vbatscale, 10, 200 },

src/config.c

@@ -13,7 +13,7 @@ master_t mcfg;  // master config struct with data independent from profiles
 config_t cfg;   // profile config struct
 const char rcChannelLetters[] = "AERT1234";
 
-static const uint8_t EEPROM_CONF_VERSION = 51;
+static const uint8_t EEPROM_CONF_VERSION = 52;
 static uint32_t enabledSensors = 0;
 static void resetConf(void);
 
@@ -209,6 +209,8 @@ static void resetConf(void)
     mcfg.gps_baudrate = 115200;
     // serial (USART1) baudrate
     mcfg.serial_baudrate = 115200;
+    mcfg.softserial_baudrate = 19200;
+    mcfg.softserial_inverted = 0;
     mcfg.looptime = 3500;
     mcfg.rssi_aux_channel = 0;
 

src/drv_pwm.c

@@ -323,11 +323,9 @@ bool pwmInit(drv_pwm_config_t *init)
         if (init->useUART && (port == PWM3 || port == PWM4))
             continue;
 
-#ifdef SOFTSERIAL_19200_LOOPBACK
         // skip softSerial ports
-        if ((port == PWM5 || port == PWM6 || port == PWM7 || port == PWM8))
+        if (init->useSoftSerial && (port == PWM5 || port == PWM6 || port == PWM7 || port == PWM8))
             continue;
-#endif
 
         // skip ADC for powerMeter if configured
         if (init->adcChannel && (init->adcChannel == port))

src/drv_pwm.h

@@ -8,6 +8,7 @@ typedef struct drv_pwm_config_t {
     bool enableInput;
     bool usePPM;
     bool useUART;
+    bool useSoftSerial;
     bool useServos;
     bool extraServos;    // configure additional 4 channels in PPM mode as servos, not motors
     bool airplane;       // fixed wing hardware config, lots of servos etc

src/drv_softserial.c

@@ -17,12 +17,16 @@ void onSerialTimer(uint8_t portIndex, uint16_t capture);
 
 uint8_t readRxSignal(softSerial_t *softSerial)
 {
-    return !(digitalIn(softSerial->rxTimerHardware->gpio, softSerial->rxTimerHardware->pin) == 0);
+    uint8_t invertedSignal = (digitalIn(softSerial->rxTimerHardware->gpio, softSerial->rxTimerHardware->pin) == 0);
+    if (softSerial->isInverted) {
+          return invertedSignal;
+    }
+    return !invertedSignal;
 }
 
 void setTxSignal(softSerial_t *softSerial, uint8_t state)
 {
-    if (state) {
+    if ((state == 1 && softSerial->isInverted == false) || (state == 0 && softSerial->isInverted == true)) {
         digitalHi(softSerial->txTimerHardware->gpio, softSerial->txTimerHardware->pin);
     } else {
         digitalLo(softSerial->txTimerHardware->gpio, softSerial->txTimerHardware->pin);
@@ -82,7 +86,7 @@ void serialOutputPortConfig(const timerHardware_t *timerHardwarePtr)
     softSerialGPIOConfig(timerHardwarePtr->gpio, timerHardwarePtr->pin, Mode_Out_PP);
 }
 
-void setupSoftSerial1(uint32_t baud)
+void setupSoftSerial1(uint32_t baud, uint8_t inverted)
 {
     int portIndex = 0;
     softSerial_t *softSerial = &(softSerialPorts[portIndex]);
@@ -90,6 +94,7 @@ void setupSoftSerial1(uint32_t baud)
     softSerial->port.vTable = softSerialVTable;
     softSerial->port.mode = MODE_RXTX;
     softSerial->port.baudRate = baud;
+    softSerial->isInverted = inverted;
 
     softSerial->rxTimerHardware = &(timerHardware[SOFT_SERIAL_1_TIMER_RX_HARDWARE]);
     softSerial->txTimerHardware = &(timerHardware[SOFT_SERIAL_1_TIMER_TX_HARDWARE]);

src/drv_softserial.h

@@ -29,6 +29,7 @@ typedef struct softSerial_s {
     uint16_t         internalRxBuffer;  // excluding start/stop bits
     uint16_t         internalTxBuffer;  // includes start and stop bits
 
+    uint8_t          isInverted;
 } softSerial_t;
 
 extern timerHardware_t* serialTimerHardware;
@@ -36,7 +37,7 @@ extern softSerial_t softSerialPorts[];
 
 extern const struct serialPortVTable softSerialVTable[];
 
-void setupSoftSerial1(uint32_t baud);
+void setupSoftSerial1(uint32_t baud, uint8_t inverted);
 
 // serialPort API
 void softSerialWriteByte(serialPort_t *instance, uint8_t ch);

src/main.c

@@ -30,6 +30,7 @@ int main(void)
     uint8_t i;
     drv_pwm_config_t pwm_params;
     drv_adc_config_t adc_params;
+    serialPort_t* loopbackPort = NULL;
 
     systemInit();
 #ifdef USE_LAME_PRINTF
@@ -59,6 +60,7 @@ int main(void)
     else
         pwm_params.airplane = false;
     pwm_params.useUART = feature(FEATURE_GPS) || feature(FEATURE_SERIALRX); // spektrum/sbus support uses UART too
+    pwm_params.useSoftSerial = feature(FEATURE_SOFTSERIAL);
     pwm_params.usePPM = feature(FEATURE_PPM);
     pwm_params.enableInput = !feature(FEATURE_SERIALRX); // disable inputs if using spektrum
     pwm_params.useServos = core.useServo;
@@ -130,11 +132,14 @@ int main(void)
         batteryInit();
 
     serialInit(mcfg.serial_baudrate);
-#ifdef SOFTSERIAL_19200_LOOPBACK
-    setupSoftSerial1(19200);
-    serialPort_t* loopbackPort = (serialPort_t*)&(softSerialPorts[0]);
-    serialPrint(loopbackPort, "LOOPBACK 19200 ENABLED\r\n");
+    
+    if (feature(FEATURE_SOFTSERIAL)) {
+      setupSoftSerial1(mcfg.softserial_baudrate, mcfg.softserial_inverted);
+#ifdef SOFTSERIAL_LOOPBACK
+      loopbackPort = (serialPort_t*)&(softSerialPorts[0]);
+      serialPrint(loopbackPort, "LOOPBACK ENABLED\r\n");
 #endif
+    }
 
     previousTime = micros();
     if (mcfg.mixerConfiguration == MULTITYPE_GIMBAL)
@@ -146,13 +151,15 @@ int main(void)
     // loopy
     while (1) {
         loop();
-#ifdef SOFTSERIAL_19200_LOOPBACK
-        while (serialTotalBytesWaiting(loopbackPort)) {
+#ifdef SOFTSERIAL_LOOPBACK
+        if (loopbackPort) {
+            while (serialTotalBytesWaiting(loopbackPort)) {
     
-            uint8_t b = serialRead(loopbackPort);
-            serialWrite(loopbackPort, b);
-            //serialWrite(core.mainport, b);
-        };
+                uint8_t b = serialRead(loopbackPort);
+                serialWrite(loopbackPort, b);
+                //serialWrite(core.mainport, b);
+            };
+        }
 #endif
     }
 }

src/mw.h

@@ -291,6 +291,9 @@ typedef struct master_t {
 
     uint32_t serial_baudrate;
     
+    uint32_t softserial_baudrate;
+    uint8_t softserial_inverted;           // use inverted softserial input and output signals
+
     config_t profile[3];                    // 3 separate profiles
     uint8_t current_profile;                // currently loaded profile