Fix SoftwareSerial/SerialPIO inversion and build (#2423)

SWSerial wasn't even building due to a typo in the header, and SerialPIO
needs to set the OE-invert flag after PIO initialization for transmit.

Fixes #2419

Author: earlephilhower

cores/rp2040/SerialPIO.cpp

@@ -201,7 +201,6 @@ void SerialPIO::begin(unsigned long baud, uint16_t config) {
 
         digitalWrite(_tx, HIGH);
         pinMode(_tx, OUTPUT);
-        gpio_set_outover(_tx, _invertTX);
 
         pio_tx_program_init(_txPIO, _txSM, off, _tx);
         pio_sm_clear_fifos(_txPIO, _txSM); // Remove any existing data
@@ -212,6 +211,7 @@ void SerialPIO::begin(unsigned long baud, uint16_t config) {
         pio_sm_exec(_txPIO, _txSM, pio_encode_mov(pio_isr, pio_osr));
 
         // Start running!
+        gpio_set_outover(_tx, _invertTX);
         pio_sm_set_enabled(_txPIO, _txSM, true);
     }
     if (_rx != NOPIN) {

cores/rp2040/SoftwareSerial.h

@@ -37,8 +37,8 @@ class SoftwareSerial : public SerialPIO {
     };
 
     void begin(unsigned long baud, uint16_t config) override {
-        setInvertTX(invert);
-        setInvertRX(invert);
+        setInvertTX(_invert);
+        setInvertRX(_invert);
         SerialPIO::begin(baud, config);
     }
 

keywords.txt

@@ -13,6 +13,7 @@ Dir	KEYWORD1
 File	KEYWORD1
 timeval	KEYWORD1
 time_t	KEYWORD1
+SoftwareSerial	KEYWORD1
 
 #######################################
 # Methods and Functions (KEYWORD2)