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Merge pull request #2058 from dave-prosee/master

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I2C bus reset with status info to user, re issue 1025
This commit is contained in:
Ivan Grokhotkov 2016-06-01 11:09:15 +08:00
commit 3cfad27e38
4 changed files with 27 additions and 0 deletions
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15
cores/esp8266/core_esp8266_si2c.c
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@ -197,3 +197,18 @@ unsigned char twi_readFrom(unsigned char address, unsigned char* buf, unsigned i
}
return 0;
}
uint8_t twi_status(){
if (SCL_READ()==0) return I2C_SCL_HELD_LOW; //SCL held low by another device, no procedure available to recover
int clockCount = 20;
while (SDA_READ()==0 && clockCount>0){ //if SDA low, read the bits slaves have to sent to a max
twi_read_bit();
if (SCL_READ()==0) return I2C_SCL_HELD_LOW_AFTER_READ; //I2C bus error. SCL held low beyond slave clock stretch time
}
if (SDA_READ()==0) return I2C_SDA_HELD_LOW; //I2C bus error. SDA line held low by slave/another_master after n bits.
if(!twi_write_start()) return I2C_SDA_HELD_LOW_AFTER_INIT; //line busy. SDA again held low by another device. 2nd master?
else return I2C_OK; //all ok
}

7
cores/esp8266/twi.h
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@ -26,12 +26,19 @@
extern "C" {
#endif
#define I2C_OK 0
#define I2C_SCL_HELD_LOW 1
#define I2C_SCL_HELD_LOW_AFTER_READ 2
#define I2C_SDA_HELD_LOW 3
#define I2C_SDA_HELD_LOW_AFTER_INIT 4
void twi_init(unsigned char sda, unsigned char scl);
void twi_stop(void);
void twi_setClock(unsigned int freq);
void twi_setClockStretchLimit(uint32_t limit);
uint8_t twi_writeTo(unsigned char address, unsigned char * buf, unsigned int len, unsigned char sendStop);
uint8_t twi_readFrom(unsigned char address, unsigned char * buf, unsigned int len, unsigned char sendStop);
uint8_t twi_status();
#ifdef __cplusplus
}

4
libraries/Wire/Wire.cpp
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@ -77,6 +77,10 @@ void TwoWire::begin(uint8_t address){
begin();
}
uint8_t TwoWire::status(){
return twi_status();
}
void TwoWire::begin(int address){
begin((uint8_t)address);
}

1
libraries/Wire/Wire.h
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@ -62,6 +62,7 @@ class TwoWire : public Stream
uint8_t endTransmission(void);
uint8_t endTransmission(uint8_t);
size_t requestFrom(uint8_t address, size_t size, bool sendStop);
uint8_t status();
uint8_t requestFrom(uint8_t, uint8_t);
uint8_t requestFrom(uint8_t, uint8_t, uint8_t);