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CurieSoftwareSerial Improvements #101

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CurieSoftwareSerial Improvements #101

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101 changes: 46 additions & 55 deletions ...es/CurieSoftwareSerial/SoftwareSerial.cpp → ...urieSoftwareSerial/src/SoftwareSerial.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -42,21 +42,17 @@ char SoftwareSerial::_receive_buffer[_SS_MAX_RX_BUFF];
volatile uint8_t SoftwareSerial::_receive_buffer_tail = 0;
volatile uint8_t SoftwareSerial::_receive_buffer_head = 0;


//
// Globals
//
uint8_t rxPin;
uint16_t bitDelay;
uint16_t rxIntraBitDelay;
int rxCenteringDelay;
int initRxIntraBitDelay;
int firstIntraBitDelay;
int initRxCenteringDelay;
bool firstStartBit = true;
bool bufferOverflow = true;
bool invertedLogic = false;
bool isSOCGpio = false;
static uint8_t _rxPin;
static uint16_t bitDelay;
static uint16_t rxIntraBitDelay;
static int rxCenteringDelay;
static int initRxIntraBitDelay;
static int firstIntraBitDelay;
static int initRxCenteringDelay;
static bool firstStartBit = true;
static bool bufferOverflow = true;
static bool invertedLogic = false;
static bool isSOCGpio = false;

//
// Debugging
Expand Down Expand Up @@ -94,14 +90,21 @@ bool SoftwareSerial::listen()
bufferOverflow = false;
_receive_buffer_head = _receive_buffer_tail = 0;
active_object = this;
rxPin = _receivePin;
_rxPin = _receivePin;
rxIntraBitDelay = _rx_delay_intrabit;
rxCenteringDelay = _rx_delay_centering;
initRxIntraBitDelay = _rx_delay_init_intrabit;
firstIntraBitDelay = _rx_delay_first_intrabit;
initRxCenteringDelay = _rx_delay_init_centering;
invertedLogic = _inverse_logic;
isSOCGpio = _isSOCGpio;
if(invertedLogic)
{
attachInterrupt(rxPin, recv, HIGH);
attachInterrupt(_rxPin, recv, HIGH);
}
else
{
attachInterrupt(rxPin, recv, LOW);
attachInterrupt(_rxPin, recv, LOW);
}

return true;
Expand All @@ -116,7 +119,7 @@ bool SoftwareSerial::stopListening()
if (active_object == this)
{
active_object = NULL;
detachInterrupt(rxPin);
detachInterrupt(_rxPin);
return true;
}
return false;
Expand All @@ -131,7 +134,7 @@ void SoftwareSerial::recv()
uint8_t d = 0;
// If RX line is high, then we don't see any start bit
// so interrupt is probably not for us
if (invertedLogic ? digitalRead(rxPin) : !digitalRead(rxPin))
if (invertedLogic ? digitalRead(_rxPin) : !digitalRead(_rxPin))
{
// The very first start bit the sketch receives takes about 5us longer
if(firstStartBit && !isSOCGpio)
Expand Down Expand Up @@ -162,7 +165,7 @@ void SoftwareSerial::recv()
delayTicks(rxIntraBitDelay);
}
d >>= 1;
if (digitalRead(rxPin))
if (digitalRead(_rxPin))
d |= 0x80;
firstStartBit = false;
}
Expand All @@ -187,15 +190,15 @@ void SoftwareSerial::recv()
uint8_t loopTimeout = 8;
if(invertedLogic)
{
while(digitalRead(rxPin) && (loopTimeout >0))
while(digitalRead(_rxPin) && (loopTimeout >0))
{
delayTicks(bitDelay >> 4);
loopTimeout--;
}
}
else
{
while(!digitalRead(rxPin) && (loopTimeout >0))
while(!digitalRead(_rxPin) && (loopTimeout >0))
{
delayTicks(bitDelay >> 4);
loopTimeout--;
Expand All @@ -208,21 +211,9 @@ void SoftwareSerial::recv()

uint32_t SoftwareSerial::rx_pin_read()
{
return digitalRead(rxPin);
return digitalRead(_rxPin);
}

//
// Interrupt handling
//

/* static */
inline void SoftwareSerial::handle_interrupt()
{
if (active_object)
{
active_object->recv();
}
}

//
// Constructor
Expand All @@ -235,7 +226,7 @@ SoftwareSerial::SoftwareSerial(uint32_t receivePin, uint32_t transmitPin, bool i
_buffer_overflow(false),
_inverse_logic(inverse_logic)
{
invertedLogic = inverse_logic;
_inverse_logic = inverse_logic;
setTX(transmitPin);
_transmitPin = transmitPin;
setRX(receivePin);
Expand Down Expand Up @@ -283,37 +274,37 @@ void SoftwareSerial::begin(long speed)
{
_rx_delay_centering = _rx_delay_intrabit = _rx_delay_stopbit = _tx_delay = 0;
//pre-calculate delays
bitDelay = (F_CPU/speed);
PinDescription *p = &g_APinDescription[rxPin];
_bit_delay = (F_CPU/speed);
PinDescription *p = &g_APinDescription[_rxPin];
if (p->ulGPIOType == SOC_GPIO)
{
isSOCGpio = true;
_isSOCGpio = true;
}
//toggling a pin takes about 62 ticks
_tx_delay = bitDelay - 62;
_tx_delay = _bit_delay - 62;
//reading a pin takes about 70 ticks
rxIntraBitDelay = bitDelay - 70;
_rx_delay_intrabit = _bit_delay - 70;
//it takes about 272 ticks from when the start bit is received to when the ISR is called
rxCenteringDelay = (bitDelay / 2 - 272 - 55);
if(rxCenteringDelay < 0)
_rx_delay_centering = (_bit_delay / 2 - 272 - 55);
if(_rx_delay_centering < 0)
{
firstIntraBitDelay = rxIntraBitDelay + rxCenteringDelay;
if(firstIntraBitDelay < 0)
firstIntraBitDelay = 0;
rxCenteringDelay = 0;
_rx_delay_first_intrabit = _rx_delay_intrabit + _rx_delay_centering;
if(_rx_delay_first_intrabit < 0)
_rx_delay_first_intrabit = 0;
_rx_delay_centering = 0;
}
else
{
firstIntraBitDelay = rxIntraBitDelay;
_rx_delay_first_intrabit = _rx_delay_intrabit;
}
//the first time the ISR is called is about 150 ticks longer
initRxCenteringDelay = rxCenteringDelay - 150;
if(initRxCenteringDelay < 0)
_rx_delay_init_centering = _rx_delay_centering - 150;
if(_rx_delay_init_centering < 0)
{
initRxIntraBitDelay = rxIntraBitDelay + initRxCenteringDelay;
if(initRxIntraBitDelay < 0)
initRxIntraBitDelay = 0;
initRxCenteringDelay = 0;
_rx_delay_init_intrabit = _rx_delay_intrabit + _rx_delay_init_centering;
if(_rx_delay_init_intrabit < 0)
_rx_delay_init_intrabit = 0;
_rx_delay_init_centering = 0;
}

#if _DEBUG
Expand Down
22 changes: 10 additions & 12 deletions ...ries/CurieSoftwareSerial/SoftwareSerial.h → .../CurieSoftwareSerial/src/SoftwareSerial.h
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Original file line number Diff line number Diff line change
Expand Up @@ -40,20 +40,20 @@ class SoftwareSerial : public Stream
// per object data
uint32_t _receivePin;
uint32_t _transmitPin;
uint32_t _receiveBitMask;
volatile uint32_t *_receivePortRegister;
uint32_t _transmitBitMask;
volatile uint32_t *_pcint_maskreg;
uint32_t _pcint_maskvalue;
uint32_t _isSOCGpio;

// delays
uint32_t _rx_delay_centering;
uint32_t _rx_delay_intrabit;
uint32_t _rx_delay_stopbit;
uint32_t _tx_delay;
int _bit_delay;
int _rx_delay_centering;
int _rx_delay_init_centering;
int _rx_delay_init_intrabit;
int _rx_delay_first_intrabit;
int _rx_delay_intrabit;
int _rx_delay_stopbit;
int _tx_delay;

uint32_t _buffer_overflow:1;
uint32_t _inverse_logic:1;
bool _inverse_logic = false;

// static data
static char _receive_buffer[_SS_MAX_RX_BUFF];
Expand Down Expand Up @@ -94,8 +94,6 @@ class SoftwareSerial : public Stream

using Print::write;

// public only for easy access by interrupt handlers
static inline void handle_interrupt() __attribute__((__always_inline__));
};

// Arduino 0012 workaround
Expand Down