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

* Copyright 2013-2014 Espressif Systems (Wuxi)

*

* FileName: i2c_master.c

*

* Description: i2c master API

*

* Modification history:

* 2014/3/12, v1.0 create this file.

* 2015/10/11, modified to work with any pin for Espruino

* 2016/05/23, modified to work with clock streching and bitrate

*

* ESPRSSIF MIT License

*

* Copyright (c) 2015 <ESPRESSIF SYSTEMS (SHANGHAI) PTE LTD>

*

* Permission is hereby granted for use on ESPRESSIF SYSTEMS ESP8266 only, in which case,

* it is free of charge, to any person obtaining a copy of this software and associated

* documentation files (the Software), to deal in the Software without restriction,

* including without limitation the rights to use, copy, modify, merge, publish, distribute,

* sublicense, and/or sell copies of the Software, and to permit persons to whom the Software

* is furnished to do so, subject to the following conditions:

*

* The above copyright notice and this permission notice shall be included in all copies

* or substantial portions of the Software.

*

* THE SOFTWARE IS PROVIDED AS IS, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,

* INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR

* PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE

* FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR

* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER

* DEALINGS IN THE SOFTWARE.

*

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

#include "ets_sys.h"

#include "osapi_release.h"

#include "gpio.h"

#include "espmissingincludes.h"

#include "i2c_master.h"

#define I2C_MASTER_SDA_SCL(sda, scl) do {\

uint32 set = ((sda&1)<<pinSDA) | ((scl&1)<<pinSCL);\

uint32 both = (1<<pinSDA) | (1<<pinSCL);\

gpio_output_set(set, set^both, both, 0);\

} while(0)

#define i2c_master_wait(x) os_delay_us(x*y)

#define i2c_master_getDC(void) ((GPIO_REG_READ(GPIO_IN_ADDRESS) >> pinSDA) & 1)

#define i2c_master_getDD(void) ((GPIO_REG_READ(GPIO_IN_ADDRESS) >> pinSCL) & 1)

LOCAL uint8 pinSDA, pinSCL; // actual gpio pins used

LOCAL uint8 y=1;

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

* FunctionName : i2c_master_setDC

* Description : Internal used function -

* set i2c SDA and SCL bit value for half clk cycle

* Parameters : uint8 SDA

* uint8 SCL

* Returns : NONE

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

LOCAL void CALLED_FROM_INTERRUPT

i2c_master_setDC(uint8 SDA, uint8 SCL)

{

SDA &= 0x01;

SCL &= 0x01;

I2C_MASTER_SDA_SCL(SDA, SCL);

}

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

* FunctionName : i2c_master_getDC

* Description : Internal used function -

* get i2c SDA bit value

* Parameters : NONE

* Returns : uint8 - SDA bit value

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

#if 0

LOCAL uint8 CALLED_FROM_INTERRUPT

i2c_master_getDC(void)

{

return (GPIO_REG_READ(GPIO_IN_ADDRESS) >> pinSDA) & 1;

}

#endif

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

* FunctionName : i2c_master_init

* Description : initilize I2C bus to enable i2c operations

* Parameters : NONE

* Returns : NONE

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

void ICACHE_FLASH_ATTR

i2c_master_init(void)

{

uint8 i;

i2c_master_setDC(1, 0);

i2c_master_wait(2);

// when SCL = 0, toggle SDA to clear up

i2c_master_setDC(0, 0) ;

i2c_master_wait(2);

i2c_master_setDC(1, 0) ;

i2c_master_wait(2);

// set data_cnt to max value

for (i = 0; i < 28; i++) {

i2c_master_setDC(1, 0);

i2c_master_wait(2); // sda 1, scl 0

i2c_master_setDC(1, 1);

i2c_master_wait(2); // sda 1, scl 1

}

return;

}

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

* FunctionName : i2c_master_gpio_init

* Description : config SDA and SCL gpio to open-drain output mode,

* mux and gpio num defined in i2c_master.h

* Parameters : NONE

* Returns : NONE

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

void ICACHE_FLASH_ATTR

i2c_master_gpio_init(uint8 scl, uint8 sda, uint32 bitrate)

{

pinSCL = scl;

pinSDA = sda;

if(bitrate > 400000) {bitrate=400000;}

if(bitrate < 100000) {bitrate=100000;}

y = 400000/bitrate;

#if 0

ETS_GPIO_INTR_DISABLE();

GPIO_REG_WRITE(GPIO_PIN_ADDR(GPIO_ID_PIN(sda)),

GPIO_REG_READ(GPIO_PIN_ADDR(GPIO_ID_PIN(sda))) |

GPIO_PIN_PAD_DRIVER_SET(GPIO_PAD_DRIVER_ENABLE)); //open drain;

GPIO_REG_WRITE(GPIO_ENABLE_ADDRESS,

GPIO_REG_READ(GPIO_ENABLE_ADDRESS) | (1 << sda));

GPIO_REG_WRITE(GPIO_PIN_ADDR(GPIO_ID_PIN(scl)),

GPIO_REG_READ(GPIO_PIN_ADDR(GPIO_ID_PIN(scl))) |

GPIO_PIN_PAD_DRIVER_SET(GPIO_PAD_DRIVER_ENABLE)); //open drain;

GPIO_REG_WRITE(GPIO_ENABLE_ADDRESS,

GPIO_REG_READ(GPIO_ENABLE_ADDRESS) | (1 << scl));

I2C_MASTER_SDA_SCL(1, 1);

ETS_GPIO_INTR_ENABLE() ;

#endif

I2C_MASTER_SDA_SCL(1, 1);

i2c_master_init();

}

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

* FunctionName : i2c_master_start

* Description : set i2c to send state

* Parameters : NONE

* Returns : NONE

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

void ICACHE_FLASH_ATTR

i2c_master_start(void)

{

i2c_master_setDC(0, 1);

i2c_master_wait(1); // sda 0, scl 1

i2c_master_setDC(0, 0);

i2c_master_wait(1); // sda 0, scl 0

}

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

* FunctionName : i2c_master_stop

* Description : set i2c to stop sending state

* Parameters : NONE

* Returns : NONE

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

void ICACHE_FLASH_ATTR

i2c_master_stop(void)

{

i2c_master_setDC(0, 1);

i2c_master_wait(1);

while (!i2c_master_getDD()) {}; // PB

i2c_master_setDC(1, 1);

i2c_master_wait(1); // sda 1, scl 1

}

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

* FunctionName : i2c_master_setAck

* Description : set ack to i2c bus as level value

* Parameters : uint8 level - 0 or 1

* Returns : NONE

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

void ICACHE_FLASH_ATTR

i2c_master_setAck(uint8 level)

{

i2c_master_setDC(level, 0);

i2c_master_wait(1); // sda level, scl 0

i2c_master_setDC(level, 1);

i2c_master_wait(1);

while (!i2c_master_getDD()) {}; // PB

i2c_master_setDC(level, 0);

i2c_master_wait(1); // sda level, scl 0

i2c_master_setDC(1, 0);

i2c_master_wait(1);

}

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

* FunctionName : i2c_master_getAck

* Description : confirm if peer send ack

* Parameters : NONE

* Returns : uint8 - ack value, 0 or 1

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

uint8 ICACHE_FLASH_ATTR

i2c_master_getAck(void)

{

uint8 retVal;

i2c_master_setDC(1, 0);

i2c_master_wait(1);

i2c_master_setDC(1, 1);

i2c_master_wait(1);

while (!i2c_master_getDD()) {}; // PB

retVal = i2c_master_getDC();

i2c_master_setDC(1, 0);

i2c_master_wait(1);

return !retVal; // 0->true->ACK, 1->false->NACK

}

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

* FunctionName : i2c_master_checkAck

* Description : get dev response

* Parameters : NONE

* Returns : true : get ack ; false : get nack

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

bool ICACHE_FLASH_ATTR

i2c_master_checkAck(void)

{

if(i2c_master_getAck()){

return FALSE;

}else{

return TRUE;

}

}

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

* FunctionName : i2c_master_send_ack

* Description : response ack

* Parameters : NONE

* Returns : NONE

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

void ICACHE_FLASH_ATTR

i2c_master_send_ack(void)

{

i2c_master_setAck(0x0);

}

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

* FunctionName : i2c_master_send_nack

* Description : response nack

* Parameters : NONE

* Returns : NONE

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

void ICACHE_FLASH_ATTR

i2c_master_send_nack(void)

{

i2c_master_setAck(0x1);

}

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

* 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;

for (i = 0; i < 8; i++) {

i2c_master_setDC(1, 1);

i2c_master_wait(1);

while (!i2c_master_getDD()) {}; // PB

retVal = (retVal<<1) | (i2c_master_getDC()&1);

i2c_master_setDC(1, 0);

i2c_master_wait(1); // sda 1, scl 0

}

return retVal;

}

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

* FunctionName : i2c_master_writeByte

* Description : write wrdata value(one byte) into i2c

* Parameters : uint8 wrdata - write value

* Returns : NONE

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

void ICACHE_FLASH_ATTR

i2c_master_writeByte(uint8 wrdata)

{

uint8 dat;

sint8 i;

for (i = 7; i >= 0; i--) {

dat = wrdata >> i;

i2c_master_setDC(dat, 0);

i2c_master_wait(1);

i2c_master_setDC(dat, 1);

i2c_master_wait(1);

while (!i2c_master_getDD()) {}; // PB

i2c_master_setDC(dat, 0);

i2c_master_wait(2);

}

}