315 lines
8.5 KiB
C
315 lines
8.5 KiB
C
/******************************************************************************
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* Copyright 2013-2014 Espressif Systems (Wuxi)
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*
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* FileName: i2c_sw_master.c
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*
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* Description: i2c master API
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*
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* Modification history:
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* 2014/3/12, v1.0 create this file.
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*******************************************************************************/
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#include "driver/gpio.h"
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#include "driver/i2c_sw_master.h"
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static uint8_t m_nLastSDA;
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static uint8_t m_nLastSCL;
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static uint8_t pinSDA;
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static uint8_t pinSCL;
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/******************************************************************************
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* FunctionName : i2c_sw_master_setDC
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* Description : Internal used function -
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* set i2c SDA and SCL bit value for half clk cycle
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* Parameters : uint8_t SDA
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* uint8_t SCL
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* Returns : NONE
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*******************************************************************************/
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static void i2c_sw_master_setDC(uint8_t SDA, uint8_t SCL)
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{
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uint8_t sclLevel;
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SDA &= 0x01;
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SCL &= 0x01;
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m_nLastSDA = SDA;
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m_nLastSCL = SCL;
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gpio_set_level(pinSDA, SDA);
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gpio_set_level(pinSCL, SCL);
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if(1 == SCL) {
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do {
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sclLevel = gpio_get_level(pinSCL);
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} while(sclLevel == 0);
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}
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}
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/******************************************************************************
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* FunctionName : i2c_sw_master_getDC
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* Description : Internal used function -
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* get i2c SDA bit value
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* Parameters : NONE
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* Returns : uint8_t - SDA bit value
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*******************************************************************************/
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static uint8_t i2c_sw_master_getDC(void)
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{
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return gpio_get_level(pinSDA);
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}
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/******************************************************************************
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* FunctionName : i2c_sw_master_init
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* Description : initilize I2C bus to enable i2c operations
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* Parameters : NONE
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* Returns : NONE
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*******************************************************************************/
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void i2c_sw_master_init(void)
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{
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uint8_t i;
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i2c_sw_master_setDC(1, 0);
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i2c_sw_master_wait(5);
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// when SCL = 0, toggle SDA to clear up
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i2c_sw_master_setDC(0, 0);
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i2c_sw_master_wait(5);
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i2c_sw_master_setDC(1, 0);
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i2c_sw_master_wait(5);
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// set data_cnt to max value
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for (i = 0; i < 28; i++) {
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i2c_sw_master_setDC(1, 0);
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i2c_sw_master_wait(5); // sda 1, scl 0
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i2c_sw_master_setDC(1, 1);
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i2c_sw_master_wait(5); // sda 1, scl 1
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}
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// reset all
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i2c_sw_master_stop();
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return;
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}
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uint8_t i2c_sw_master_get_pinSDA()
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{
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return pinSDA;
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}
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uint8_t i2c_sw_master_get_pinSCL()
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{
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return pinSCL;
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}
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/******************************************************************************
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* FunctionName : i2c_sw_master_gpio_init
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* Description : config SDA and SCL gpio to open-drain output mode,
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* mux and gpio num defined in i2c_sw_master.h
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* Parameters : NONE
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* Returns : NONE
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*******************************************************************************/
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void i2c_sw_master_gpio_init(uint8 sda, uint8 scl)
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{
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pinSDA = sda;
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pinSCL = scl;
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gpio_config_t cfg;
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cfg.pin_bit_mask = 1 << sda | 1 << scl;
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cfg.mode = GPIO_MODE_INPUT_OUTPUT_OD;
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cfg.pull_up_en = GPIO_PULLUP_ENABLE;
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cfg.pull_down_en = GPIO_PULLDOWN_DISABLE;
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cfg.intr_type = GPIO_INTR_DISABLE;
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if (ESP_OK != gpio_config(&cfg))
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return;
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gpio_set_level(scl, 1);
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gpio_set_level(sda, 1);
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i2c_sw_master_init();
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}
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/******************************************************************************
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* FunctionName : i2c_sw_master_start
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* Description : set i2c to send state
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* Parameters : NONE
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* Returns : NONE
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*******************************************************************************/
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void i2c_sw_master_start(void)
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{
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i2c_sw_master_setDC(1, m_nLastSCL);
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i2c_sw_master_wait(5);
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i2c_sw_master_setDC(1, 1);
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i2c_sw_master_wait(5); // sda 1, scl 1
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i2c_sw_master_setDC(0, 1);
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i2c_sw_master_wait(5); // sda 0, scl 1
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}
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/******************************************************************************
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* FunctionName : i2c_sw_master_stop
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* Description : set i2c to stop sending state
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* Parameters : NONE
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* Returns : NONE
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*******************************************************************************/
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void i2c_sw_master_stop(void)
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{
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i2c_sw_master_wait(5);
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i2c_sw_master_setDC(0, m_nLastSCL);
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i2c_sw_master_wait(5); // sda 0
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i2c_sw_master_setDC(0, 1);
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i2c_sw_master_wait(5); // sda 0, scl 1
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i2c_sw_master_setDC(1, 1);
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i2c_sw_master_wait(5); // sda 1, scl 1
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}
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/******************************************************************************
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* FunctionName : i2c_sw_master_setAck
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* Description : set ack to i2c bus as level value
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* Parameters : uint8_t level - 0 or 1
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* Returns : NONE
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*******************************************************************************/
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void i2c_sw_master_setAck(uint8_t level)
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{
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i2c_sw_master_setDC(m_nLastSDA, 0);
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i2c_sw_master_wait(5);
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i2c_sw_master_setDC(level, 0);
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i2c_sw_master_wait(5); // sda level, scl 0
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i2c_sw_master_setDC(level, 1);
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i2c_sw_master_wait(8); // sda level, scl 1
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i2c_sw_master_setDC(level, 0);
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i2c_sw_master_wait(5); // sda level, scl 0
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i2c_sw_master_setDC(1, 0);
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i2c_sw_master_wait(5);
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}
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/******************************************************************************
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* FunctionName : i2c_sw_master_getAck
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* Description : confirm if peer send ack
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* Parameters : NONE
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* Returns : uint8_t - ack value, 0 or 1
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*******************************************************************************/
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uint8_t i2c_sw_master_getAck(void)
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{
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uint8_t retVal;
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i2c_sw_master_setDC(m_nLastSDA, 0);
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i2c_sw_master_wait(5);
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i2c_sw_master_setDC(1, 0);
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i2c_sw_master_wait(5);
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i2c_sw_master_setDC(1, 1);
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i2c_sw_master_wait(5);
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retVal = i2c_sw_master_getDC();
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i2c_sw_master_wait(5);
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i2c_sw_master_setDC(1, 0);
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i2c_sw_master_wait(5);
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return retVal;
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}
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/******************************************************************************
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* FunctionName : i2c_sw_master_checkAck
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* Description : get dev response
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* Parameters : NONE
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* Returns : true : get ack ; false : get nack
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*******************************************************************************/
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bool i2c_sw_master_checkAck(void)
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{
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if (i2c_sw_master_getAck()) {
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return false;
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} else {
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return true;
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}
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}
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/******************************************************************************
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* FunctionName : i2c_sw_master_send_ack
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* Description : response ack
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* Parameters : NONE
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* Returns : NONE
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*******************************************************************************/
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void i2c_sw_master_send_ack(void)
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{
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i2c_sw_master_setAck(0x0);
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}
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/******************************************************************************
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* FunctionName : i2c_sw_master_send_nack
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* Description : response nack
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* Parameters : NONE
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* Returns : NONE
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*******************************************************************************/
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void i2c_sw_master_send_nack(void)
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{
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i2c_sw_master_setAck(0x1);
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}
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/******************************************************************************
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* FunctionName : i2c_sw_master_readByte
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* Description : read Byte from i2c bus
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* Parameters : NONE
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* Returns : uint8_t - readed value
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*******************************************************************************/
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uint8_t i2c_sw_master_readByte(void)
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{
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uint8_t retVal = 0;
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uint8_t k, i;
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i2c_sw_master_wait(5);
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i2c_sw_master_setDC(m_nLastSDA, 0);
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i2c_sw_master_wait(5); // sda 1, scl 0
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for (i = 0; i < 8; i++) {
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i2c_sw_master_wait(5);
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i2c_sw_master_setDC(1, 0);
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i2c_sw_master_wait(5); // sda 1, scl 0
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i2c_sw_master_setDC(1, 1);
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i2c_sw_master_wait(5); // sda 1, scl 1
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k = i2c_sw_master_getDC();
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i2c_sw_master_wait(5);
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if (i == 7) {
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i2c_sw_master_wait(3);
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}
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k <<= (7 - i);
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retVal |= k;
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}
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i2c_sw_master_setDC(1, 0);
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i2c_sw_master_wait(5); // sda 1, scl 0
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return retVal;
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}
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/******************************************************************************
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* FunctionName : i2c_sw_master_writeByte
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* Description : write wrdata value(one byte) into i2c
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* Parameters : uint8_t wrdata - write value
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* Returns : NONE
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*******************************************************************************/
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void i2c_sw_master_writeByte(uint8_t wrdata)
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{
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uint8_t dat;
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int8_t i;
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i2c_sw_master_wait(5);
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i2c_sw_master_setDC(m_nLastSDA, 0);
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i2c_sw_master_wait(5);
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for (i = 7; i >= 0; i--) {
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dat = wrdata >> i;
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i2c_sw_master_setDC(dat, 0);
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i2c_sw_master_wait(5);
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i2c_sw_master_setDC(dat, 1);
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i2c_sw_master_wait(5);
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if (i == 0) {
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i2c_sw_master_wait(3);
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}
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i2c_sw_master_setDC(dat, 0);
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i2c_sw_master_wait(5);
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}
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}
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