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i2c: increase the default clock strech timeout to 250msec.

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This also redefines the timeout in FreeRTOS clock ticks, and implements a two
stage wait: firstly spinning sampling frequently, and then falling back to a
longer wait while sampling less frequently and yielding.
This commit is contained in:
Our Air Quality 2018-06-15 08:22:29 +10:00
parent d9c5f2eaa2
commit c8c7f97290
2 changed files with 42 additions and 23 deletions
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11
extras/i2c/i2c.h
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@ -32,6 +32,8 @@
#include <stdint.h>
#include <stdbool.h>
#include <errno.h>
#include <FreeRTOS.h>
#include <task.h>
#ifdef __cplusplus
extern "C" {
@ -51,7 +53,8 @@ extern "C" {
#define I2C_USE_GPIO16 0
#endif
#define I2C_DEFAULT_CLK_STRETCH (10)
/* Default clock strech waiting time, 250 msec. */
#define I2C_DEFAULT_CLK_STRETCH (250 / portTICK_PERIOD_MS)
/* SCL speed settings. 160 MHz sysclk frequency will result in improved
* timing accuracy. Greater bitrates will have poorer accuracy. 1000K is the
@ -86,7 +89,6 @@ typedef struct i2c_dev
* @param scl_pin SCL pin for I2C
* @param sda_pin SDA pin for I2C
* @param freq frequency of bus (ex : I2C_FREQ_400K)
* @param clk_stretch I2C clock stretch. I2C_DEFAULT_CLK_STRETCH would be good in most cases
* @return Non-zero if error occured
*/
int i2c_init(uint8_t bus, uint8_t scl_pin, uint8_t sda_pin, i2c_freq_t freq);
@ -97,7 +99,6 @@ int i2c_init(uint8_t bus, uint8_t scl_pin, uint8_t sda_pin, i2c_freq_t freq);
* @param scl_pin SCL pin for I2C
* @param sda_pin SDA pin for I2C
* @param freq frequency of bus in hertz
* @param clk_stretch I2C clock stretch. I2C_DEFAULT_CLK_STRETCH would be good in most cases
* @return Non-zero if error occured
*/
int i2c_init_hz(uint8_t bus, uint8_t scl_pin, uint8_t sda_pin, uint32_t freq);
@ -119,9 +120,9 @@ int i2c_set_frequency_hz(uint8_t bus, uint32_t freq);
/**
* Change clock stretch
* @param bus I2C bus
* @param clk_stretch I2C clock stretch. I2C_DEFAULT_CLK_STRETCH by default
* @param clk_stretch I2C clock stretch, in ticks. I2C_DEFAULT_CLK_STRETCH by default
*/
void i2c_set_clock_stretch(uint8_t bus, uint32_t clk_stretch);
void i2c_set_clock_stretch(uint8_t bus, TickType_t clk_stretch);
/**
* Write a byte to I2C bus.