TasmotaSerial:

- Added transmit parity to software TX.  Software RX just consumes in the incoming parity bit with no error checking.
- Fixed issue where Serial.begin for the ESP8266 was not passing the UART SerialConfig compatible values.

support.ino
- Cleanup to use already present ConvertSerialConfig API.

tasmota.ino:
- Force the baudrate + serial config settings after boot.  Previously, the baudrate would change, but any non 8N1 settings were not applied.

xdrv_08_serial_bridge.ino:
- Increased the software serial bridge buffer size and changed type to prevent overflow.
- Added missing serial config settings to the serial begin.  Previously was forcing 8N1.

xdrv_10_scripter.ino
- Cleanup to use already present ConvertSerialConfig API.

lib/default/TasmotaSerial-3.3.0/src/TasmotaSerial.cpp

@@ -55,6 +55,7 @@ TasmotaSerial::TasmotaSerial(int receive_pin, int transmit_pin, int hardware_fal
   m_hardserial = false;
   m_hardswap = false;
   m_stop_bits = 1;
+  m_parity = -1;
   m_nwmode = nwmode;
   serial_buffer_size = buffer_size;
   m_rx_pin = receive_pin;
@@ -121,26 +122,23 @@ bool TasmotaSerial::isValidGPIOpin(int pin) {
 
 bool TasmotaSerial::begin(uint32_t speed, uint32_t config) {
   if (!m_valid) { return false; }
-  if (config > 2) {
-    // Legacy support where software serial fakes two stop bits if either stop bits is 2 or parity is not None
-    m_stop_bits = ((config &0x30) >> 5) +1;
-    if ((1 == m_stop_bits) && (config &0x03)) {
-      m_stop_bits++;
+  // get the number of stop bits
+  m_stop_bits = (config &0x20) ? 2 : 1;
+  // check for parity
+  if (config &0x02) {           // parity is enabled
+    if (config &0x01) {
+      m_parity = HIGH;          // odd parity
+    } else {
+      m_parity = LOW;           // even parity
     }
   } else {
-    m_stop_bits = ((config -1) &1) +1;
-#ifdef ESP8266
-    config = (2 == m_stop_bits) ? (uint32_t)SERIAL_8N2 : (uint32_t)SERIAL_8N1;
-#endif  // ESP8266
-#ifdef ESP32
-    config = (2 == m_stop_bits) ? SERIAL_8N2 : SERIAL_8N1;
-#endif  // ESP32
+    m_parity = -1;              // no parity
   }
 
   if (m_hardserial) {
 #ifdef ESP8266
     Serial.flush();
-    Serial.begin(speed, (SerialConfig)config);
+    Serial.begin(speed, (SerialConfig)ConvertSerialConfig(config));
     if (m_hardswap) {
       Serial.swap();
     }
@@ -285,14 +283,23 @@ int TasmotaSerial::available(void) {
 void IRAM_ATTR TasmotaSerial::_fast_write(uint8_t b) {
   uint32_t wait = m_bit_time;
   uint32_t start = ESP.getCycleCount();
+  uint8_t numOnes = 0;
+  uint8_t bit;
   // Start bit;
   digitalWrite(m_tx_pin, LOW);
   TM_SERIAL_WAIT_SND_FAST;
   for (uint32_t i = 0; i < 8; i++) {
-    digitalWrite(m_tx_pin, (b & 1) ? HIGH : LOW);
+    bit = (b &1);
+    numOnes += bit;
+    digitalWrite(m_tx_pin, bit ? HIGH : LOW);
     TM_SERIAL_WAIT_SND_FAST;
     b >>= 1;
   }
+  // parity bit
+  if (m_parity != -1) {
+    digitalWrite(m_tx_pin, (numOnes %2) ? !m_parity : m_parity);
+    TM_SERIAL_WAIT_SND_FAST;
+  }
   // Stop bit(s)
   digitalWrite(m_tx_pin, HIGH);
   for (uint32_t i = 0; i < m_stop_bits; i++) {
@@ -318,14 +325,23 @@ size_t TasmotaSerial::write(uint8_t b) {
       uint32_t wait = m_bit_time;
       //digitalWrite(m_tx_pin, HIGH);     // already in HIGH mode
       uint32_t start = ESP.getCycleCount();
+      uint8_t numOnes = 0;
+      uint8_t bit;      
       // Start bit;
       digitalWrite(m_tx_pin, LOW);
       TM_SERIAL_WAIT_SND;
       for (uint32_t i = 0; i < 8; i++) {
-        digitalWrite(m_tx_pin, (b & 1) ? HIGH : LOW);
+        bit = (b &1);
+        numOnes += bit;     
+        digitalWrite(m_tx_pin, bit ? HIGH : LOW);        
         TM_SERIAL_WAIT_SND;
         b >>= 1;
       }
+      // parity bit
+      if (m_parity != -1) {
+        digitalWrite(m_tx_pin, (numOnes %2) ? !m_parity : m_parity);
+        TM_SERIAL_WAIT_SND;
+      }      
       // Stop bit(s)
       digitalWrite(m_tx_pin, HIGH);
       // re-enable interrupts during stop bits, it's not an issue if they are longer than expected
@@ -359,6 +375,12 @@ void IRAM_ATTR TasmotaSerial::rxRead(void) {
         m_in_pos = next;
       }
 
+      // just consume the parity bit -- no parity checking is occuring
+      if (m_parity != -1) {
+        TM_SERIAL_WAIT_RCV_LOOP;  // wait for the parity bit
+        wait += m_bit_time / 4;
+      }
+
       TM_SERIAL_WAIT_RCV_LOOP;    // wait for stop bit
       if (2 == m_stop_bits) {
         wait += m_bit_time;

lib/default/TasmotaSerial-3.3.0/src/TasmotaSerial.h

@@ -35,6 +35,8 @@
 #include <HardwareSerial.h>
 #endif
 
+extern uint32_t ConvertSerialConfig(uint8_t serial_config);
+
 class TasmotaSerial : public Stream {
   public:
     TasmotaSerial(int receive_pin, int transmit_pin, int hardware_fallback = 0, int nwmode = 0, int buffer_size = TM_SERIAL_BUFFER_SIZE);
@@ -68,6 +70,7 @@ class TasmotaSerial : public Stream {
     int m_rx_pin;
     int m_tx_pin;
     uint32_t m_stop_bits;
+    uint32_t m_parity;  
     uint32_t ss_byte;
     uint32_t ss_bstart;
     uint32_t ss_index;

tasmota/support.ino

@@ -1885,15 +1885,14 @@ void SetSerialBegin(void) {
   AddLog(LOG_LEVEL_INFO, PSTR(D_LOG_SERIAL "Set to %s %d bit/s"), GetSerialConfig().c_str(), TasmotaGlobal.baudrate);
   Serial.flush();
 #ifdef ESP8266
-  Serial.begin(TasmotaGlobal.baudrate, (SerialConfig)pgm_read_byte(kTasmotaSerialConfig + Settings->serial_config));
+  Serial.begin(TasmotaGlobal.baudrate, (SerialConfig)ConvertSerialConfig(Settings->serial_config));
   SetSerialSwap();
 #endif  // ESP8266
 #ifdef ESP32
   delay(10);  // Allow time to cleanup queues - if not used hangs ESP32
   Serial.end();
   delay(10);  // Allow time to cleanup queues - if not used hangs ESP32
-  uint32_t config = pgm_read_dword(kTasmotaSerialConfig + Settings->serial_config);
-  Serial.begin(TasmotaGlobal.baudrate, config);
+  Serial.begin(TasmotaGlobal.baudrate, ConvertSerialConfig(Settings->serial_config));
 #endif  // ESP32
 }
 

tasmota/tasmota.ino

@@ -337,7 +337,7 @@ void setup(void) {
     Settings->baudrate = APP_BAUDRATE / 300;
     Settings->serial_config = TS_SERIAL_8N1;
   }
-  SetSerialBaudrate(Settings->baudrate * 300);  // Reset serial interface if current baudrate is different from requested baudrate
+  SetSerialBegin();                            // Reset serial interface if current serial settings are different from requested serial settings
 
   if (1 == RtcReboot.fast_reboot_count) {      // Allow setting override only when all is well
     UpdateQuickPowerCycle(true);

tasmota/xdrv_08_serial_bridge.ino

@@ -25,7 +25,7 @@
 #define XDRV_08                    8
 #define HARDWARE_FALLBACK          2
 
-const uint8_t SERIAL_BRIDGE_BUFFER_SIZE = 130;
+const uint16_t SERIAL_BRIDGE_BUFFER_SIZE = 256;
 
 const char kSerialBridgeCommands[] PROGMEM = "|"  // No prefix
   D_CMND_SSERIALSEND "|" D_CMND_SBAUDRATE;
@@ -106,7 +106,13 @@ void SerialBridgeInit(void)
   serial_bridge_active = false;
   if (PinUsed(GPIO_SBR_RX) && PinUsed(GPIO_SBR_TX)) {
     SerialBridgeSerial = new TasmotaSerial(Pin(GPIO_SBR_RX), Pin(GPIO_SBR_TX), HARDWARE_FALLBACK);
-    if (SerialBridgeSerial->begin(Settings->sbaudrate * 300)) {  // Baud rate is stored div 300 so it fits into 16 bits
+#ifdef ESP8266
+    if (SerialBridgeSerial->begin(Settings->sbaudrate * 300, (SerialConfig)ConvertSerialConfig(Settings->serial_config)))  // Baud rate is stored div 300 so it fits into 16 bits
+#endif  // ESP8266
+#ifdef ESP32
+    if (SerialBridgeSerial->begin(Settings->sbaudrate * 300, ConvertSerialConfig(Settings->serial_config)))  // Baud rate is stored div 300 so it fits into 16 bits
+#endif  // ESP32    
+    {
       if (SerialBridgeSerial->hardwareSerial()) {
         ClaimSerial();
         serial_bridge_buffer = TasmotaGlobal.serial_in_buffer;  // Use idle serial buffer to save RAM

tasmota/xdrv_10_scripter.ino

@@ -3620,15 +3620,7 @@ chknext:
             glob_script_mem.sp = new TasmotaSerial(rxpin, txpin, 1, 0, rxbsiz);
 
             if (glob_script_mem.sp) {
-              uint32_t config;
-#ifdef ESP8266
-              config = pgm_read_byte(kTasmotaSerialConfig + sconfig);
-#endif  // ESP8266
-
-#ifdef ESP32
-              config = pgm_read_dword(kTasmotaSerialConfig + sconfig);
-#endif // ESP32
-              fvar = glob_script_mem.sp->begin(br, config);
+              fvar = glob_script_mem.sp->begin(br, ConvertSerialConfig(sconfig));
               uint32_t savc = Settings->serial_config;
               //setRxBufferSize(TMSBSIZ);