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I2C ReSTART returns Success #2141

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Merged
merged 3 commits into from
Dec 3, 2018
Merged

I2C ReSTART returns Success #2141

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2fc395c
Don't Return I2C_ERROR_CONTINUE on ReSTART
stickbreaker Nov 29, 2018
1de3dda
add comments
stickbreaker Nov 29, 2018
b805117
Change Return error for ReSTART operation to I2C_ERROR_OK
stickbreaker Dec 2, 2018
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28 changes: 18 additions & 10 deletions libraries/Wire/src/Wire.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -154,14 +154,15 @@ void TwoWire::beginTransmission(uint16_t address)
uint8_t TwoWire::endTransmission(bool sendStop) // Assumes Wire.beginTransaction(), Wire.write()
{
if(transmitting == 1) {
// txlength is howmany bytes in txbuffer have been use
last_error = writeTransmission(txAddress, &txBuffer[txQueued], txLength - txQueued, sendStop);
rxIndex = 0;
rxLength = rxQueued;
rxQueued = 0;
txQueued = 0; // the SendStop=true will restart all Queueing
if(last_error == I2C_ERROR_CONTINUE){
// txlength is howmany bytes in txbuffer have been use
txQueued = txLength;
} else if( last_error == I2C_ERROR_OK){
rxIndex = 0;
rxLength = rxQueued;
rxQueued = 0;
txQueued = 0; // the SendStop=true will restart all Queueing
}
} else {
last_error = I2C_ERROR_NO_BEGIN;
Expand All @@ -170,7 +171,7 @@ uint8_t TwoWire::endTransmission(bool sendStop) // Assumes Wire.beginTransactio
txIndex = 0;
txLength = 0;
transmitting = 0;
return last_error;
return (last_error == I2C_ERROR_CONTINUE)?I2C_ERROR_OK:last_error; // Don't return Continue for compatibility.
}

/* @stickBreaker 11/2017 fix for ReSTART timeout, ISR
Expand All @@ -191,12 +192,19 @@ uint8_t TwoWire::requestFrom(uint16_t address, uint8_t size, bool sendStop)

last_error = readTransmission(address, &rxBuffer[cnt], size, sendStop, &cnt);
rxIndex = 0;
rxLength = rxQueued;
rxQueued = 0;
txQueued = 0; // the SendStop=true will restart all Queueing
if(last_error != I2C_ERROR_OK){

rxLength = cnt;

if( last_error != I2C_ERROR_CONTINUE){ // not a buffered ReSTART operation
// so this operation actually moved data, queuing is done.
rxQueued = 0;
txQueued = 0; // the SendStop=true will restart all Queueing or error condition
}

if(last_error != I2C_ERROR_OK){ // ReSTART on read does not return any data
cnt = 0;
}

return cnt;
}

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6 changes: 4 additions & 2 deletions libraries/Wire/src/Wire.h
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Original file line number Diff line number Diff line change
Expand Up @@ -67,12 +67,13 @@ class TwoWire: public Stream
public:
TwoWire(uint8_t bus_num);
~TwoWire();
bool begin(int sda=-1, int scl=-1, uint32_t frequency=0);
bool begin(int sda=-1, int scl=-1, uint32_t frequency=0); // returns true, if successful init of i2c bus
// calling will attemp to recover hung bus

void setClock(uint32_t frequency); // change bus clock without initing hardware
size_t getClock(); // current bus clock rate in hz

void setTimeOut(uint16_t timeOutMillis);
void setTimeOut(uint16_t timeOutMillis); // default timeout of i2c transactions is 50ms
uint16_t getTimeOut();

uint8_t lastError();
Expand Down Expand Up @@ -137,6 +138,7 @@ extern TwoWire Wire1;


/*
V1.0.2 30NOV2018 stop returning I2C_ERROR_CONTINUE on ReSTART operations, regain compatibility with Arduino libs
V1.0.1 02AUG2018 First Fix after release, Correct ReSTART handling, change Debug control, change begin()
to a function, this allow reporting if bus cannot be initialized, Wire.begin() can be used to recover
a hung bus busy condition.
Expand Down