Labrador/Desktop_Interface/i2cdecoder.cpp

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#include "i2cdecoder.h"
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using namespace i2c;
i2cDecoder::i2cDecoder(isoBuffer* sda_in, isoBuffer* scl_in, QPlainTextEdit* console_in)
: QObject(nullptr)
, sda(sda_in)
, scl(scl_in)
, console(console_in)
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{
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serialBuffer = new isoBufferBuffer(I2C_BUFFER_LENGTH);
updateTimer = new QTimer();
updateTimer->setTimerType(Qt::PreciseTimer);
updateTimer->start(CONSOLE_UPDATE_TIMER_PERIOD);
connect(updateTimer, SIGNAL(timeout()), this, SLOT(updateConsole()));
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}
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void i2cDecoder::reset()
{
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qDebug () << "Resetting I2C";
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if (sda->back != scl->back)
{
// Perhaps the data could be saved, but just resetting them seems much safer
sda->clearBuffer();
scl->clearBuffer();
}
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serialPtr_bit = sda->back * 8;
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{
std::lock_guard<std::mutex> lock(mutex);
delete serialBuffer;
serialBuffer = new isoBufferBuffer(I2C_BUFFER_LENGTH);
}
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}
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void i2cDecoder::run()
{
// qDebug() << "i2cDecoder::run()";
while (serialDistance(sda) > SERIAL_DELAY * sda->sampleRate_bit)
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{
updateBitValues();
runStateMachine();
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serialPtr_bit ++;
if (serialPtr_bit > (sda->bufferEnd * 8))
serialPtr_bit -= (sda->bufferEnd * 8);
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}
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}
int i2cDecoder::serialDistance(isoBuffer* buffer)
{
int back_bit = buffer->back * 8;
int bufferEnd_bit = buffer->bufferEnd * 8;
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if (back_bit >= serialPtr_bit)
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return back_bit - serialPtr_bit;
else
return bufferEnd_bit - serialPtr_bit + back_bit;
}
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void i2cDecoder::updateBitValues(){
previousSdaValue = currentSdaValue;
previousSclValue = currentSclValue;
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int coord_byte = serialPtr_bit/8;
int coord_bit = serialPtr_bit - (8*coord_byte);
unsigned char dataByteSda = sda->buffer[coord_byte];
unsigned char dataByteScl = scl->buffer[coord_byte];
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unsigned char mask = (0x01 << coord_bit);
currentSdaValue = dataByteSda & mask;
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currentSclValue = dataByteScl & mask;
}
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void i2cDecoder::runStateMachine()
{
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edge sdaEdge = edgeDetection(currentSdaValue, previousSdaValue);
edge sclEdge = edgeDetection(currentSclValue, previousSclValue);
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// if (sdaEdge == edge::rising || sdaEdge == edge::falling)
// qDebug() << "sdaEdge";
// if (sclEdge == edge::rising || sclEdge == edge::falling)
// qDebug() << "sclEdge";
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// if (sclEdge != edge::held_low)
// qDebug() << "sdaEdge" << (uint8_t)sdaEdge << "sclEdge" << (uint8_t)sclEdge;
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if ((sdaEdge == edge::rising) && (sclEdge == edge::falling)) // INVALID STATE TRANSITION
{
state = transmissionState::unknown;
qDebug() << "Dumping I2C state and aborting...";
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for (int i=31; i>=0; i--)
qDebug("%02x\t%02x", sda->buffer[serialPtr_bit/8 - i] & 0xFF, scl->buffer[serialPtr_bit/8 - i] & 0xFF);
throw std::runtime_error("unknown i2c transmission state");
return;
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}
if ((sdaEdge == edge::rising) && (sclEdge == edge::held_high)) // START
{
stopCondition();
return;
}
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if ((sdaEdge == edge::falling) && (sclEdge == edge::held_high)) // STOP
{
startCondition();
return;
}
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switch (state)
{
case transmissionState::idle:
return;
case transmissionState::address:
decodeAddress(sdaEdge, sclEdge);
break;
case transmissionState::data:
decodeData(sdaEdge, sclEdge);
break;
}
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}
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edge i2cDecoder::edgeDetection(uint8_t current, uint8_t prev)
{
if (current && prev)
return edge::held_high;
if (!current && !prev)
return edge::held_low;
if (current && !prev)
return edge::rising;
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if (!current && prev)
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return edge::falling;
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throw std::runtime_error("i2c Edge Detection critical failure");
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}
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void i2cDecoder::decodeAddress(edge sdaEdge, edge sclEdge)
{
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// Read in the next bit.
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if (sclEdge == edge::rising && sdaEdge == edge::held_high && currentBitIndex++ < addressBitStreamLength)
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currentBitStream = (currentBitStream << 1) | 0x0001;
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else if (sclEdge == edge::rising && sdaEdge == edge::held_low && currentBitIndex++ < addressBitStreamLength)
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currentBitStream = (currentBitStream << 1) & 0xFFFE;
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else
return;
if (currentBitIndex == addressBitStreamLength)
{
qDebug() << "Finished Address Decode";
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if (currentBitStream & 0b0000000000000010)
serialBuffer->add("READ: ");
else
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serialBuffer->add("WRITE: ");
char addressStr[8];
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sprintf(addressStr, "0x%02x ", (currentBitStream & 0b0000000111111100) >> 2);
serialBuffer->add(addressStr);
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if (currentBitStream & 0b0000000000000001)
serialBuffer->add("(NACK)");
consoleStateInvalid = true;
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// Prepare for next bit
currentBitIndex = 0;
currentBitStream = 0x0000;
state = transmissionState::data;
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}
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}
void i2cDecoder::decodeData(edge sdaEdge, edge sclEdge)
{
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// Read in the next bit.
if (sclEdge == edge::rising && sdaEdge == edge::held_high && currentBitIndex++ < dataBitStreamLength)
currentBitStream = (currentBitStream << 1) | 0x0001;
else if (sclEdge == edge::rising && sdaEdge == edge::held_low && currentBitIndex++ < dataBitStreamLength)
currentBitStream = (currentBitStream << 1) & 0xFFFE;
else
return;
if (currentBitIndex == dataBitStreamLength)
{
qDebug() << "Finished Data byte Decode";
char dataStr[8];
sprintf(dataStr, "0x%02x ", (currentBitStream & 0b0000000111111110) >> 1);
serialBuffer->add(dataStr);
if (currentBitStream & 0b0000000000000001)
serialBuffer->add("(NACK)");
consoleStateInvalid = true;
// Prepare for next bit
currentBitIndex = 0;
currentBitStream = 0x0000;
}
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}
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void i2cDecoder::startCondition()
{
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currentBitIndex = 0;
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currentBitStream = 0x0000;
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state = transmissionState::address;
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qDebug() << "I2C START";
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}
void i2cDecoder::stopCondition()
{
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state = transmissionState::idle;
serialBuffer->add('\n');
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qDebug() << "I2C STOP";
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}
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void i2cDecoder::updateConsole(){
std::lock_guard<std::mutex> lock(mutex);
if (!consoleStateInvalid)
return;
uint32_t numCharsInBuffer = serialBuffer->getNumCharsInBuffer();
console->setPlainText(QString::fromLocal8Bit(serialBuffer->get(numCharsInBuffer), numCharsInBuffer));
if(sda->serialAutoScroll){
QTextCursor c = console->textCursor();
c.movePosition(QTextCursor::End);
console->setTextCursor(c);
}
consoleStateInvalid = false;
}