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Add new Wire.sendTo(...) and Wire.requestFrom(...) API's that use external buffer #269

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Add new Wire.sendTo(...) and Wire.requestFrom(...) API's that use external buffer #269

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3d5ebc4
Add new Wire:sendTo(...) and Wire.requestFrom(...) API's that use ext…
sandeepmistry Oct 16, 2017
44032f7
Make Wire.endTransmission(...) use new Wire.sendTo(...)
sandeepmistry Oct 16, 2017
7d4bd13
Rename sentTo -> sendTo
sandeepmistry Nov 22, 2017
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88 changes: 60 additions & 28 deletions libraries/Wire/Wire.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -62,7 +62,53 @@ void TwoWire::end() {
sercom->disableWIRE();
}

uint8_t TwoWire::sendTo(uint8_t address, uint8_t buffer[], size_t quantity)
{
return sendTo(address, buffer, quantity, true);
}

uint8_t TwoWire::sendTo(uint8_t address, uint8_t buffer[], size_t quantity, bool stopBit)
{
// Start I2C transmission
if (!sercom->startTransmissionWIRE(address, WIRE_WRITE_FLAG))
{
sercom->prepareCommandBitsWire(WIRE_MASTER_ACT_STOP);
return 2 ; // Address error
}

for (size_t i = 0; i < quantity; i++) {
// Try to send data
if (!sercom->sendDataMasterWIRE(buffer[i]))
{
sercom->prepareCommandBitsWire(WIRE_MASTER_ACT_STOP);
return 3 ; // Nack or error
}
}

if (stopBit)
{
sercom->prepareCommandBitsWire(WIRE_MASTER_ACT_STOP);
}

return 0;
}

uint8_t TwoWire::requestFrom(uint8_t address, size_t quantity)
{
return requestFrom(address, quantity, true);
}

uint8_t TwoWire::requestFrom(uint8_t address, size_t quantity, bool stopBit)
{
return requestFrom(address, NULL, quantity, stopBit);
}

uint8_t TwoWire::requestFrom(uint8_t address, uint8_t buffer[], size_t quantity)
{
return requestFrom(address, buffer, quantity, true);
}

uint8_t TwoWire::requestFrom(uint8_t address, uint8_t buffer[], size_t quantity, bool stopBit)
{
if(quantity == 0)
{
Expand All @@ -76,14 +122,22 @@ uint8_t TwoWire::requestFrom(uint8_t address, size_t quantity, bool stopBit)
if(sercom->startTransmissionWIRE(address, WIRE_READ_FLAG))
{
// Read first data
rxBuffer.store_char(sercom->readDataWIRE());
if (buffer == NULL) {
rxBuffer.store_char(sercom->readDataWIRE());
} else {
buffer[0] = sercom->readDataWIRE();
}

// Connected to slave
for (byteRead = 1; byteRead < quantity; ++byteRead)
{
sercom->prepareAckBitWIRE(); // Prepare Acknowledge
sercom->prepareCommandBitsWire(WIRE_MASTER_ACT_READ); // Prepare the ACK command for the slave
rxBuffer.store_char(sercom->readDataWIRE()); // Read data and send the ACK
if (buffer == NULL) {
rxBuffer.store_char(sercom->readDataWIRE()); // Read data and send the ACK
} else {
buffer[byteRead] = sercom->readDataWIRE();
}
}
sercom->prepareNackBitWIRE(); // Prepare NACK to stop slave transmission
//sercom->readDataWIRE(); // Clear data register to send NACK
Expand All @@ -97,11 +151,6 @@ uint8_t TwoWire::requestFrom(uint8_t address, size_t quantity, bool stopBit)
return byteRead;
}

uint8_t TwoWire::requestFrom(uint8_t address, size_t quantity)
{
return requestFrom(address, quantity, true);
}

void TwoWire::beginTransmission(uint8_t address) {
// save address of target and clear buffer
txAddress = address;
Expand All @@ -120,30 +169,13 @@ uint8_t TwoWire::endTransmission(bool stopBit)
{
transmissionBegun = false ;

// Start I2C transmission
if ( !sercom->startTransmissionWIRE( txAddress, WIRE_WRITE_FLAG ) )
{
sercom->prepareCommandBitsWire(WIRE_MASTER_ACT_STOP);
return 2 ; // Address error
}
uint8_t result = sendTo(txAddress, txBuffer._aucBuffer, txBuffer.available(), stopBit);

// Send all buffer
while( txBuffer.available() )
{
// Trying to send data
if ( !sercom->sendDataMasterWIRE( txBuffer.read_char() ) )
{
sercom->prepareCommandBitsWire(WIRE_MASTER_ACT_STOP);
return 3 ; // Nack or error
}
if (result == 0) {
txBuffer.clear();
}

if (stopBit)
{
sercom->prepareCommandBitsWire(WIRE_MASTER_ACT_STOP);
}

return 0;
return result;
}

uint8_t TwoWire::endTransmission()
Expand Down
5 changes: 5 additions & 0 deletions libraries/Wire/Wire.h
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Original file line number Diff line number Diff line change
Expand Up @@ -42,8 +42,13 @@ class TwoWire : public Stream
uint8_t endTransmission(bool stopBit);
uint8_t endTransmission(void);

uint8_t sendTo(uint8_t address, uint8_t buffer[], size_t quantity);
uint8_t sendTo(uint8_t address, uint8_t buffer[], size_t quantity, bool stopBit);

uint8_t requestFrom(uint8_t address, size_t quantity, bool stopBit);
uint8_t requestFrom(uint8_t address, size_t quantity);
uint8_t requestFrom(uint8_t address, uint8_t buffer[], size_t quantity);
uint8_t requestFrom(uint8_t address, uint8_t buffer[], size_t quantity, bool stopBit);

size_t write(uint8_t data);
size_t write(const uint8_t * data, size_t quantity);
Expand Down