Fix outdated README, source comments for readParity. Fix dropped 0xff octets. (#205)

* Fixes #203 

* Check for hidden stop bit at the end of each rxBits. Fixes first-octet in session dropped issue, and

intermittently dropped octets, in particular the delay(2000), issue. 

* Fixes #204 

* Use precise enum value identifier in sample code.

Author: dok-net

README.md

@@ -79,9 +79,10 @@ argument to ``begin()``. Word lengths can be set to between 5 and 8 bits, parity
 can be N(one), O(dd) or E(ven) and 1 or 2 stop bits can be used. The default is
 ``SWSERIAL_8N1`` using 8 bits, no parity and 1 stop bit but any combination can
 be used, e.g. ``SWSERIAL_7E2``. If using EVEN or ODD parity, any parity errors
-can be detected with the ``peekParityError()`` function. Note that parity 
-checking must be done before ``read()``, as the parity information is removed
-from the buffer when reading the corresponding byte.
+can be detected with the ``readParity()`` and ``parityEven()`` or ``parityOdd()``
+functions respectively. Note that the result of ``readParity()`` always applies
+to the preceding ``read()`` or ``peek()`` call, and is undefined if they report
+no data or an error.
 
 To allow flexible 9-bit and data/addressing protocols, the additional parity
 modes MARK and SPACE are also available. Furthermore, the parity mode can be
@@ -93,8 +94,8 @@ up SoftwareSerial with parity mode SPACE, e.g. ``SWSERIAL_8S1``. This will add a
 parity bit to every byte sent, setting it to logical zero (SPACE parity).
 
 To detect incoming bytes with the parity bit set (MARK parity), use the
-``peekParityError()`` function. To send a byte with the parity bit set, just add
-``MARK`` as the second argument when writing, e.g. ``write(ch, MARK)``.
+``readParity()`` function. To send a byte with the parity bit set, just add
+``MARK`` as the second argument when writing, e.g. ``write(ch, SWSERIAL_PARITY_MARK)``.
 
 ## Using and updating EspSoftwareSerial in the esp8266com/esp8266 Arduino build environment
 

library.json

@@ -1,6 +1,6 @@
 {
     "name": "EspSoftwareSerial",
-    "version": "6.12.0",
+    "version": "6.12.1",
     "keywords": [
       "serial", "io", "softwareserial"
     ],

library.properties

@@ -1,5 +1,5 @@
 name=EspSoftwareSerial
-version=6.12.0
+version=6.12.1
 author=Dirk Kaar, Peter Lerup
 maintainer=Dirk Kaar <dok@dok-net.net>
 sentence=Implementation of the Arduino software serial for ESP8266/ESP32.

src/SoftwareSerial.cpp

@@ -421,7 +421,6 @@ int SoftwareSerial::peek() {
 }
 
 void SoftwareSerial::rxBits() {
-    int isrAvail = m_isrBuffer->available();
 #ifdef ESP8266
     if (m_isrOverflow.load()) {
         m_overflow = true;
@@ -433,19 +432,18 @@ void SoftwareSerial::rxBits() {
     }
 #endif
 
+    m_isrBuffer->for_each([this](const uint32_t& isrCycle) { rxBits(isrCycle); });
+
     // stop bit can go undetected if leading data bits are at same level
     // and there was also no next start bit yet, so one byte may be pending.
-    // low-cost check first
-    if (!isrAvail && m_rxCurBit >= -1 && m_rxCurBit < m_pduBits - m_stopBits) {
+    if (m_rxCurBit >= -1 && m_rxCurBit < m_pduBits - m_stopBits) {
         uint32_t detectionCycles = (m_pduBits - m_stopBits - m_rxCurBit) * m_bitCycles;
         if (ESP.getCycleCount() - m_isrLastCycle > detectionCycles) {
             // Produce faux stop bit level, prevents start bit maldetection
             // cycle's LSB is repurposed for the level bit
             rxBits(((m_isrLastCycle + detectionCycles) | 1) ^ m_invert);
         }
     }
-
-    m_isrBuffer->for_each([this](const uint32_t& isrCycle) { rxBits(isrCycle); });
 }
 
 void SoftwareSerial::rxBits(const uint32_t& isrCycle) {

src/SoftwareSerial.h

@@ -138,7 +138,7 @@ class SoftwareSerial : public Stream {
     }
     int peek() override;
     int read() override;
-    /// @returns The verbatim parity bit associated with the last read() or peek() call
+    /// @returns The verbatim parity bit associated with the last successful read() or peek() call
     bool readParity()
     {
         return m_lastReadParity;