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nodemcu-firmware/app/driver/i2c_master.c

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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.
*******************************************************************************/
#include "ets_sys.h"
#include "osapi.h"
#include "gpio.h"
#include "driver/i2c_master.h"
#include "pin_map.h"
LOCAL uint8 m_nLastSDA;
LOCAL uint8 m_nLastSCL;
LOCAL uint8 pinSDA = 2;
LOCAL uint8 pinSCL = 15;
/******************************************************************************
* 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 ICACHE_FLASH_ATTR
i2c_master_setDC(uint8 SDA, uint8 SCL)
{
SDA &= 0x01;
SCL &= 0x01;
m_nLastSDA = SDA;
m_nLastSCL = SCL;
if ((0 == SDA) && (0 == SCL)) {
I2C_MASTER_SDA_LOW_SCL_LOW();
} else if ((0 == SDA) && (1 == SCL)) {
I2C_MASTER_SDA_LOW_SCL_HIGH();
} else if ((1 == SDA) && (0 == SCL)) {
I2C_MASTER_SDA_HIGH_SCL_LOW();
} else {
I2C_MASTER_SDA_HIGH_SCL_HIGH();
}
}
/******************************************************************************
* FunctionName : i2c_master_getDC
* Description : Internal used function -
* get i2c SDA bit value
* Parameters : NONE
* Returns : uint8 - SDA bit value
*******************************************************************************/
LOCAL uint8 ICACHE_FLASH_ATTR
i2c_master_getDC(void)
{
uint8 sda_out;
sda_out = GPIO_INPUT_GET(GPIO_ID_PIN(I2C_MASTER_SDA_GPIO));
return sda_out;
}
/******************************************************************************
* 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(5);
// when SCL = 0, toggle SDA to clear up
i2c_master_setDC(0, 0) ;
i2c_master_wait(5);
i2c_master_setDC(1, 0) ;
i2c_master_wait(5);
// set data_cnt to max value
for (i = 0; i < 28; i++) {
i2c_master_setDC(1, 0);
i2c_master_wait(5); // sda 1, scl 0
i2c_master_setDC(1, 1);
i2c_master_wait(5); // sda 1, scl 1
}
// reset all
i2c_master_stop();
return;
}
uint8 i2c_master_get_pinSDA(){
return pinSDA;
}
uint8 i2c_master_get_pinSCL(){
return pinSCL;
}
/******************************************************************************
* 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 sda, uint8 scl)
{
pinSDA = pin_num[sda];
pinSCL = pin_num[scl];
ETS_GPIO_INTR_DISABLE() ;
// ETS_INTR_LOCK();
PIN_FUNC_SELECT(I2C_MASTER_SDA_MUX, I2C_MASTER_SDA_FUNC);
PIN_FUNC_SELECT(I2C_MASTER_SCL_MUX, I2C_MASTER_SCL_FUNC);
GPIO_REG_WRITE(GPIO_PIN_ADDR(GPIO_ID_PIN(I2C_MASTER_SDA_GPIO)), GPIO_REG_READ(GPIO_PIN_ADDR(GPIO_ID_PIN(I2C_MASTER_SDA_GPIO))) | GPIO_PIN_PAD_DRIVER_SET(GPIO_PAD_DRIVER_ENABLE)); //open drain;
GPIO_REG_WRITE(GPIO_ENABLE_ADDRESS, GPIO_REG_READ(GPIO_ENABLE_ADDRESS) | (1 << I2C_MASTER_SDA_GPIO));
GPIO_REG_WRITE(GPIO_PIN_ADDR(GPIO_ID_PIN(I2C_MASTER_SCL_GPIO)), GPIO_REG_READ(GPIO_PIN_ADDR(GPIO_ID_PIN(I2C_MASTER_SCL_GPIO))) | GPIO_PIN_PAD_DRIVER_SET(GPIO_PAD_DRIVER_ENABLE)); //open drain;
GPIO_REG_WRITE(GPIO_ENABLE_ADDRESS, GPIO_REG_READ(GPIO_ENABLE_ADDRESS) | (1 << I2C_MASTER_SCL_GPIO));
I2C_MASTER_SDA_HIGH_SCL_HIGH();
ETS_GPIO_INTR_ENABLE() ;
// ETS_INTR_UNLOCK();
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(1, m_nLastSCL);
i2c_master_wait(5);
i2c_master_setDC(1, 1);
i2c_master_wait(5); // sda 1, scl 1
i2c_master_setDC(0, 1);
i2c_master_wait(5); // sda 0, scl 1
}
/******************************************************************************
* 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_wait(5);
i2c_master_setDC(0, m_nLastSCL);
i2c_master_wait(5); // sda 0
i2c_master_setDC(0, 1);
i2c_master_wait(5); // sda 0, scl 1
i2c_master_setDC(1, 1);
i2c_master_wait(5); // 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(m_nLastSDA, 0);
i2c_master_wait(5);
i2c_master_setDC(level, 0);
i2c_master_wait(5); // sda level, scl 0
i2c_master_setDC(level, 1);
i2c_master_wait(8); // sda level, scl 1
i2c_master_setDC(level, 0);
i2c_master_wait(5); // sda level, scl 0
i2c_master_setDC(1, 0);
i2c_master_wait(5);
}
/******************************************************************************
* 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(m_nLastSDA, 0);
i2c_master_wait(5);
i2c_master_setDC(1, 0);
i2c_master_wait(5);
i2c_master_setDC(1, 1);
i2c_master_wait(5);
retVal = i2c_master_getDC();
i2c_master_wait(5);
i2c_master_setDC(1, 0);
i2c_master_wait(5);
return retVal;
}
/******************************************************************************
* 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 k, i;
i2c_master_wait(5);
i2c_master_setDC(m_nLastSDA, 0);
i2c_master_wait(5); // sda 1, scl 0
for (i = 0; i < 8; i++) {
i2c_master_wait(5);
i2c_master_setDC(1, 0);
i2c_master_wait(5); // sda 1, scl 0
i2c_master_setDC(1, 1);
i2c_master_wait(5); // sda 1, scl 1
k = i2c_master_getDC();
i2c_master_wait(5);
if (i == 7) {
i2c_master_wait(3); ////
}
k <<= (7 - i);
retVal |= k;
}
i2c_master_setDC(1, 0);
i2c_master_wait(5); // 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;
i2c_master_wait(5);
i2c_master_setDC(m_nLastSDA, 0);
i2c_master_wait(5);
for (i = 7; i >= 0; i--) {
dat = wrdata >> i;
i2c_master_setDC(dat, 0);
i2c_master_wait(5);
i2c_master_setDC(dat, 1);
i2c_master_wait(5);
if (i == 0) {
i2c_master_wait(3); ////
}
i2c_master_setDC(dat, 0);
i2c_master_wait(5);
}
}
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