I2C clock streching on esp8266.

I have made clock streching for HTU21D.
I need to get JsError to work. I've tried different header file, but I get compile errors.
Any help is welcome.

I made a git clone from @TVE and made some changes to the file: Espruino / targets / esp8266 / i2c_master.c.

Here are the file:

[#define](https://forum.espruino.com/search/?q=%23define) i2c_master_getDD(void) ((GPIO_REG_READ(GPIO_IN_ADDRESS) >> pinSCL) & 1) // PB

/****************************************************************************** PB
 * FunctionName : i2c_master_getDD
 * Description  : Internal used function -
 *                    get i2c SCL bit value
 * Parameters   : NONE
 * Returns      : uint8 - SCL bit value
*******************************************************************************/
[#if](https://forum.espruino.com/search/?q=%23if) 0
LOCAL uint8 CALLED_FROM_INTERRUPT
i2c_master_getDD(void)
{
    return (GPIO_REG_READ(GPIO_IN_ADDRESS) >> pinSCL) & 1;
}
[#endif](https://forum.espruino.com/search/?q=%23endif)

/******************************************************************************

/******************************************************************************
 * FunctionName : i2c_master_readByte
 * Description  : read Byte from i2c bus
 * Parameters   : NONE
 * Returns      : uint8 - readed value
*******************************************************************************/
uint8 ICACHE_FLASH_ATTR
i2c_master_readByte(void)
{
    uint8 retVal = 0;
    uint8 i;

    i2c_master_wait(2);
    i2c_master_setDC(m_nLastSDA, 0);
    i2c_master_wait(4);	// sda 1, scl 0

    for (i = 0; i < 8; i++) {
        i2c_master_setDC(1, 0);
        i2c_master_wait(4);	// sda 1, scl 0
        i2c_master_setDC(1, 1);
        i2c_master_wait(3);	// sda 1, scl 1
        uint8 count = 200; // max 50ms/14bit // PB 50000/1000*4=200
        while (i2c_master_getDD()==0 && count--) { // PB 36000/1000*4=144
          i2c_master_wait(1000); // wait 1000/4=250 usec // PB
        };
		if(count==0) { // PB
          goto error;
        };
        //retVal = (retVal<<1) | (i2c_master_getDC()&1);
        retVal = (retVal<<1) | (i2c_master_getDC()); // PB
    }
    i2c_master_setDC(1, 0);
    i2c_master_wait(2);	// sda 1, scl 0

    return retVal;
error:
  i2c_master_stop();
//  jsError("> I2C streching too long\n");
  return -1;
}

Should I mention it is on a esp8266-01 from my Pico kickstarter set.

1 Attachment

• i2c_master.c