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I2C code formatting, README fix (#462)

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Ruslan V. Uss 2017-10-12 17:42:34 +05:00 committed by GitHub
parent b520735d20
commit 87a3503f93
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13
extras/i2c/README.md
View file

@ -2,11 +2,12 @@
This time a driver for the excellent esp-open-rtos. This is a bit banging I2C driver based on the Wikipedia pesudo C code [1]. This time a driver for the excellent esp-open-rtos. This is a bit banging I2C driver based on the Wikipedia pesudo C code [1].
### Usage ### Basic usage
```` ```C
#include <i2c.h> #include <i2c.h>
#define BUS (0)
#define SCL_PIN (0) #define SCL_PIN (0)
#define SDA_PIN (2) #define SDA_PIN (2)
@ -14,19 +15,19 @@ uint8_t slave_addr = 0x20;
uint8_t reg_addr = 0x1f; uint8_t reg_addr = 0x1f;
uint8_t reg_data; uint8_t reg_data;
i2c_init(SCL_PIN, SDA_PIN); i2c_init(BUS, SCL_PIN, SDA_PIN, I2C_FREQ_400K);
// Write 1 byte to slave register // Write 1 byte to slave register
int err = i2c_slave_write(slave_addr, &reg_addr, &data, 1); int err = i2c_slave_write(BUS, slave_addr, &reg_addr, &data, 1);
if (err != 0) if (err != 0)
{ {
// do something with error // do something with error
} }
// Issue write to slave, sending reg_addr, followed by reading 1 byte // Issue write to slave, sending reg_addr, followed by reading 1 byte
err = i2c_slave_read(slave_addr, &reg_addr, &reg_data, 1); err = i2c_slave_read(BUS, slave_addr, &reg_addr, &reg_data, 1);
```` ```
For details please see `extras/i2c/i2c.h`. For details please see `extras/i2c/i2c.h`.

102
extras/i2c/i2c.c
View file

@ -22,10 +22,13 @@
* THE SOFTWARE. * THE SOFTWARE.
*/ */
#include "i2c.h"
#include <esp8266.h> #include <esp8266.h>
#include <espressif/esp_misc.h> // sdk_os_delay_us #include <espressif/esp_misc.h> // sdk_os_delay_us
#include <espressif/esp_system.h> #include <espressif/esp_system.h>
#include "i2c.h" #include <FreeRTOS.h>
#include <task.h>
//#define I2C_DEBUG true //#define I2C_DEBUG true
@ -37,7 +40,28 @@
#define CLK_STRETCH (10) #define CLK_STRETCH (10)
static uint8_t freq ; // Store CPU frequency for optimisation speed in delay function ( Warning: Don't change CPU frequency during a transaction) // Following array contain delay values for different frequencies
// Warning: 1 is minimal, that mean at 80MHz clock, frequency max is 320kHz
const static uint8_t i2c_freq_array[][2] = {
[I2C_FREQ_80K] = {255, 35},
[I2C_FREQ_100K] = {100, 20},
[I2C_FREQ_400K] = {10, 1},
[I2C_FREQ_500K] = {6, 1}
};
static uint8_t freq; // Store CPU frequency for optimisation speed in delay function (Warning: Don't change CPU frequency during a transaction)
// Bus settings
typedef struct i2c_bus_description
{
uint8_t g_scl_pin; // SCL pin
uint8_t g_sda_pin; // SDA pin
i2c_freq_t frequency; // Frequency
bool started;
bool flag;
bool force;
} i2c_bus_description_t;
static i2c_bus_description_t i2c_bus[MAX_I2C_BUS]; static i2c_bus_description_t i2c_bus[MAX_I2C_BUS];
inline bool i2c_status(uint8_t bus) inline bool i2c_status(uint8_t bus)
@ -48,10 +72,10 @@ inline bool i2c_status(uint8_t bus)
void i2c_init(uint8_t bus, uint8_t scl_pin, uint8_t sda_pin, i2c_freq_t freq) void i2c_init(uint8_t bus, uint8_t scl_pin, uint8_t sda_pin, i2c_freq_t freq)
{ {
i2c_bus[bus].started = false; i2c_bus[bus].started = false;
i2c_bus[bus].flag = false ; i2c_bus[bus].flag = false;
i2c_bus[bus].g_scl_pin = scl_pin; i2c_bus[bus].g_scl_pin = scl_pin;
i2c_bus[bus].g_sda_pin = sda_pin; i2c_bus[bus].g_sda_pin = sda_pin;
i2c_bus[bus].frequency = freq ; i2c_bus[bus].frequency = freq;
// Just to prevent these pins floating too much if not connected. // Just to prevent these pins floating too much if not connected.
gpio_set_pullup(i2c_bus[bus].g_scl_pin, 1, 1); gpio_set_pullup(i2c_bus[bus].g_scl_pin, 1, 1);
@ -73,7 +97,7 @@ void i2c_init(uint8_t bus, uint8_t scl_pin, uint8_t sda_pin, i2c_freq_t freq)
void i2c_frequency(uint8_t bus, i2c_freq_t freq) void i2c_frequency(uint8_t bus, i2c_freq_t freq)
{ {
i2c_bus[bus].frequency = freq ; i2c_bus[bus].frequency = freq;
} }
static inline void i2c_delay(uint8_t bus) static inline void i2c_delay(uint8_t bus)
@ -136,13 +160,14 @@ void i2c_start(uint8_t bus)
(void) read_sda(bus); (void) read_sda(bus);
i2c_delay(bus); i2c_delay(bus);
uint32_t clk_stretch = CLK_STRETCH; uint32_t clk_stretch = CLK_STRETCH;
while (read_scl(bus) == 0 && clk_stretch--) ; while (read_scl(bus) == 0 && clk_stretch--)
;
// Repeated start setup time, minimum 4.7us // Repeated start setup time, minimum 4.7us
i2c_delay(bus); i2c_delay(bus);
} }
i2c_bus[bus].started = true; i2c_bus[bus].started = true;
if (read_sda(bus) == 0) { if (read_sda(bus) == 0) {
debug("arbitration lost in i2c_start from bus %u",bus); debug("arbitration lost in i2c_start from bus %u", bus);
} }
// SCL is high, set SDA from 1 to 0. // SCL is high, set SDA from 1 to 0.
clear_sda(bus); clear_sda(bus);
@ -158,17 +183,18 @@ bool i2c_stop(uint8_t bus)
clear_sda(bus); clear_sda(bus);
i2c_delay(bus); i2c_delay(bus);
// Clock stretching // Clock stretching
while (read_scl(bus) == 0 && clk_stretch--) ; while (read_scl(bus) == 0 && clk_stretch--)
;
// Stop bit setup time, minimum 4us // Stop bit setup time, minimum 4us
i2c_delay(bus); i2c_delay(bus);
// SCL is high, set SDA from 0 to 1 // SCL is high, set SDA from 0 to 1
if (read_sda(bus) == 0) { if (read_sda(bus) == 0) {
debug("arbitration lost in i2c_stop from bus %u",bus); debug("arbitration lost in i2c_stop from bus %u", bus);
} }
i2c_delay(bus); i2c_delay(bus);
if (!i2c_bus[bus].started) { if (!i2c_bus[bus].started) {
debug("bus %u link was break!",bus); debug("bus %u link was break!", bus);
return false ; //If bus was stop in other way, the current transmission Failed return false; // If bus was stop in other way, the current transmission Failed
} }
i2c_bus[bus].started = false; i2c_bus[bus].started = false;
return true; return true;
@ -185,11 +211,12 @@ static void i2c_write_bit(uint8_t bus, bool bit)
} }
i2c_delay(bus); i2c_delay(bus);
// Clock stretching // Clock stretching
while (read_scl(bus) == 0 && clk_stretch--) ; while (read_scl(bus) == 0 && clk_stretch--)
;
// SCL is high, now data is valid // SCL is high, now data is valid
// If SDA is high, check that nobody else is driving SDA // If SDA is high, check that nobody else is driving SDA
if (bit && read_sda(bus) == 0) { if (bit && read_sda(bus) == 0) {
debug("arbitration lost in i2c_write_bit from bus %u",bus); debug("arbitration lost in i2c_write_bit from bus %u", bus);
} }
i2c_delay(bus); i2c_delay(bus);
clear_scl(bus); clear_scl(bus);
@ -204,7 +231,8 @@ static bool i2c_read_bit(uint8_t bus)
(void) read_sda(bus); (void) read_sda(bus);
i2c_delay(bus); i2c_delay(bus);
// Clock stretching // Clock stretching
while (read_scl(bus) == 0 && clk_stretch--) ; while (read_scl(bus) == 0 && clk_stretch--)
;
// SCL is high, now data is valid // SCL is high, now data is valid
bit = read_sda(bus); bit = read_sda(bus);
i2c_delay(bus); i2c_delay(bus);
@ -217,7 +245,7 @@ bool i2c_write(uint8_t bus, uint8_t byte)
bool nack; bool nack;
uint8_t bit; uint8_t bit;
for (bit = 0; bit < 8; bit++) { for (bit = 0; bit < 8; bit++) {
i2c_write_bit(bus,(byte & 0x80) != 0); i2c_write_bit(bus, (byte & 0x80) != 0);
byte <<= 1; byte <<= 1;
} }
nack = i2c_read_bit(bus); nack = i2c_read_bit(bus);
@ -231,22 +259,22 @@ uint8_t i2c_read(uint8_t bus, bool ack)
for (bit = 0; bit < 8; bit++) { for (bit = 0; bit < 8; bit++) {
byte = ((byte << 1)) | (i2c_read_bit(bus)); byte = ((byte << 1)) | (i2c_read_bit(bus));
} }
i2c_write_bit(bus,ack); i2c_write_bit(bus, ack);
return byte; return byte;
} }
void i2c_force_bus(uint8_t bus, bool state) void i2c_force_bus(uint8_t bus, bool state)
{ {
i2c_bus[bus].force = state ; i2c_bus[bus].force = state;
} }
static int i2c_bus_test(uint8_t bus) static int i2c_bus_test(uint8_t bus)
{ {
taskENTER_CRITICAL(); // To prevent task swaping after checking flag and before set it! taskENTER_CRITICAL(); // To prevent task swaping after checking flag and before set it!
bool status = i2c_bus[bus].flag ; // get current status bool status = i2c_bus[bus].flag; // get current status
if(i2c_bus[bus].force) if(i2c_bus[bus].force)
{ {
i2c_bus[bus].flag = true ; // force bus on i2c_bus[bus].flag = true; // force bus on
taskEXIT_CRITICAL(); taskEXIT_CRITICAL();
if(status) if(status)
i2c_stop(bus); //Bus was busy, stop it. i2c_stop(bus); //Bus was busy, stop it.
@ -258,72 +286,72 @@ static int i2c_bus_test(uint8_t bus)
taskEXIT_CRITICAL(); taskEXIT_CRITICAL();
debug("busy"); debug("busy");
taskYIELD(); // If bus busy, change task to try finish last com. taskYIELD(); // If bus busy, change task to try finish last com.
return -EBUSY ; // If bus busy, inform user return -EBUSY; // If bus busy, inform user
} }
else else
{ {
i2c_bus[bus].flag = true ; // Set Bus busy i2c_bus[bus].flag = true; // Set Bus busy
taskEXIT_CRITICAL(); taskEXIT_CRITICAL();
} }
} }
return 0 ; return 0;
} }
int i2c_slave_write(uint8_t bus, uint8_t slave_addr, const uint8_t *data, const uint8_t *buf, uint32_t len) int i2c_slave_write(uint8_t bus, uint8_t slave_addr, const uint8_t *data, const uint8_t *buf, uint32_t len)
{ {
if(i2c_bus_test(bus)) if(i2c_bus_test(bus))
return -EBUSY ; return -EBUSY;
i2c_start(bus); i2c_start(bus);
if (!i2c_write(bus, slave_addr << 1)) if (!i2c_write(bus, slave_addr << 1))
goto error; goto error;
if(data != NULL) if(data != NULL)
if (!i2c_write(bus,*data)) if (!i2c_write(bus, *data))
goto error; goto error;
while (len--) { while (len--) {
if (!i2c_write(bus,*buf++)) if (!i2c_write(bus, *buf++))
goto error; goto error;
} }
if (!i2c_stop(bus)) if (!i2c_stop(bus))
goto error; goto error;
i2c_bus[bus].flag = false ; // Bus free i2c_bus[bus].flag = false; // Bus free
return 0; return 0;
error: error:
debug("Bus %u Write Error",bus); debug("Bus %u Write Error", bus);
i2c_stop(bus); i2c_stop(bus);
i2c_bus[bus].flag = false ; // Bus free i2c_bus[bus].flag = false; // Bus free
return -EIO; return -EIO;
} }
int i2c_slave_read(uint8_t bus, uint8_t slave_addr, const uint8_t *data, uint8_t *buf, uint32_t len) int i2c_slave_read(uint8_t bus, uint8_t slave_addr, const uint8_t *data, uint8_t *buf, uint32_t len)
{ {
if(i2c_bus_test(bus)) if(i2c_bus_test(bus))
return -EBUSY ; return -EBUSY;
if(data != NULL) { if(data != NULL) {
i2c_start(bus); i2c_start(bus);
if (!i2c_write(bus,slave_addr << 1)) if (!i2c_write(bus, slave_addr << 1))
goto error; goto error;
if (!i2c_write(bus,*data)) if (!i2c_write(bus, *data))
goto error; goto error;
if (!i2c_stop(bus)) if (!i2c_stop(bus))
goto error; goto error;
} }
i2c_start(bus); i2c_start(bus);
if (!i2c_write(bus,slave_addr << 1 | 1)) // Slave address + read if (!i2c_write(bus, slave_addr << 1 | 1)) // Slave address + read
goto error; goto error;
while(len) { while(len) {
*buf = i2c_read(bus,len == 1); *buf = i2c_read(bus, len == 1);
buf++; buf++;
len--; len--;
} }
if (!i2c_stop(bus)) if (!i2c_stop(bus))
goto error; goto error;
i2c_bus[bus].flag = false ; // Bus free i2c_bus[bus].flag = false; // Bus free
return 0; return 0;
error: error:
debug("Read Error"); debug("Read Error");
i2c_stop(bus); i2c_stop(bus);
i2c_bus[bus].flag = false ; // Bus free i2c_bus[bus].flag = false; // Bus free
return -EIO; return -EIO;
} }

66
extras/i2c/i2c.h
View file

@ -21,6 +21,10 @@
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE. * THE SOFTWARE.
*/ */
/**
* I2C driver for ESP8266 written for use with esp-open-rtos
* Based on https://en.wikipedia.org/wiki/I²C#Example_of_bit-banging_the_I.C2.B2C_Master_protocol
*/
#ifndef __I2C_H__ #ifndef __I2C_H__
#define __I2C_H__ #define __I2C_H__
@ -28,62 +32,36 @@
#include <stdint.h> #include <stdint.h>
#include <stdbool.h> #include <stdbool.h>
#include <errno.h> #include <errno.h>
#include <FreeRTOS.h>
#include <task.h>
#ifdef __cplusplus #ifdef __cplusplus
extern "C" { extern "C" {
#endif #endif
/**
/* * Define i2c bus max number
* Define i2c bus max number
*/ */
#define MAX_I2C_BUS 2 #ifndef MAX_I2C_BUS
#define MAX_I2C_BUS 2
#endif
typedef enum
/* {
* following array contain value for different frequency I2C_FREQ_80K = 0,//!< I2C_FREQ_80K
* Warning : 1 is minimal, that mean at 80MHz clock, frequency max is 320kHz I2C_FREQ_100K, //!< I2C_FREQ_100K
* Array format is { {160MHz, 80MHz} , {160MHz, 80MHz} , ... } I2C_FREQ_400K, //!< I2C_FREQ_400K
*/ I2C_FREQ_500K, //!< I2C_FREQ_500K
#define NB_FREQ_AVAILABLE 4
typedef enum {
I2C_FREQ_80K = 0,
I2C_FREQ_100K,
I2C_FREQ_400K,
I2C_FREQ_500K,
} i2c_freq_t; } i2c_freq_t;
const static uint8_t i2c_freq_array[NB_FREQ_AVAILABLE][2] = { {255,35}, {100,20}, {10,1}, {6,1} } ;
/** /**
* Device descriptor * Device descriptor
*/ */
typedef struct i2c_dev { typedef struct i2c_dev
uint8_t bus ; {
uint8_t addr ; uint8_t bus;
} i2c_dev_t ; uint8_t addr;
} i2c_dev_t;
/** /// Level 0 API
* Bus settings
*/
typedef struct i2c_bus_description {
uint8_t g_scl_pin; // Scl pin
uint8_t g_sda_pin; // Sda pin
uint8_t frequency; // frequency selection
bool started;
bool flag;
bool force;
} i2c_bus_description_t ;
// I2C driver for ESP8266 written for use with esp-open-rtos
// Based on https://en.wikipedia.org/wiki/I²C#Example_of_bit-banging_the_I.C2.B2C_Master_protocol
// With calling overhead, we end up at ~320kbit/s
//Level 0 API
/** /**
* Init bitbanging I2C driver on given pins * Init bitbanging I2C driver on given pins
@ -137,7 +115,7 @@ bool i2c_stop(uint8_t bus);
*/ */
bool i2c_status(uint8_t bus); bool i2c_status(uint8_t bus);
//Level 1 API (Don't need functions above) /// Level 1 API (Don't need functions above)
/** /**
* This function will allow you to force a transmission I2C, cancel current transmission. * This function will allow you to force a transmission I2C, cancel current transmission.