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I2C ReSTART returns Success (#2141)

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* Don't Return I2C_ERROR_CONTINUE on ReSTART

ReSTART operations on the ESP32 have to be handled differently than on AVR chips, so ReSTART operations(`Wire.endTransmission(false), Wire.requestFrom(id,size,false);` are queued until a STOP is send (`Wire.endTransmission(TRUE), Wire.endTransmission(), Wire.requestFrom(id,size), Wire.requestFrom(id,size,TRUE)). To indicate the queuing I had used `I2C_ERROR_CONTINUE`, this caused compatibility issues with the existing Arduino I2C Code base. So, back to Lying to the public(for their own good of course) about success!  This update just returns `I2C_ERROR_OK` on ReSTART commands.

* add comments

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* Change Return error for ReSTART operation to I2C_ERROR_OK

This change restores compatibility with pre-existing Arduino Libraries.  The ReSTART queuing operations are hidden behind the scenes.  Wire.endTransmission(id,len,FALSE); will know return I2C_ERROR_OK instead of I2C_ERROR_CONTINUE, Wire.lastError() will return the true condition of I2C_ERROR_CONTINUE.
This commit is contained in:
chuck todd 2018-12-03 08:16:43 -07:00 committed by Me No Dev
parent 8aa6e2e143
commit 7a332864ab
2 changed files with 23 additions and 13 deletions
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22
libraries/Wire/src/Wire.cpp
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@ -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);
if(last_error == I2C_ERROR_CONTINUE){
txQueued = txLength;
} else if( last_error == I2C_ERROR_OK){
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 {
last_error = I2C_ERROR_NO_BEGIN;
@ -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
@ -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;
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
if(last_error != I2C_ERROR_OK){
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;
}

6
libraries/Wire/src/Wire.h
View File

@ -67,12 +67,13 @@ protected:
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();
@ -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.