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/******************************************************************************
* 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);
}
}