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esp8266: Clean up bit-bang I2C implementation. 

Changed from using set_sda_scl function to independent set_sda and
set_scl functions.
This commit is contained in:
Damien George 2016-03-14 11:54:52 +00:00 committed by Paul Sokolovsky
parent 667d64b430
commit 5b9f361824
1 changed files with 28 additions and 29 deletions
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57
esp8266/modpybi2c.c
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@ -40,22 +40,22 @@ typedef struct _pyb_i2c_obj_t {
mp_obj_base_t base;
pyb_pin_obj_t *scl;
pyb_pin_obj_t *sda;
uint8_t prev_sda;
uint8_t prev_scl;
} pyb_i2c_obj_t;
// these set the frequency of SCL
#define mphal_i2c_wait_a() os_delay_us(2)
#define mphal_i2c_wait_b() os_delay_us(1)
STATIC void mphal_i2c_set_sda_scl(pyb_i2c_obj_t *self, uint8_t sda, uint8_t scl) {
STATIC void mphal_i2c_set_sda(pyb_i2c_obj_t *self, uint8_t sda) {
uint32_t port = self->sda->phys_port;
sda &= 0x01;
gpio_output_set(sda << port, (1 - sda) << port, 1 << port, 0);
}
STATIC void mphal_i2c_set_scl(pyb_i2c_obj_t *self, uint8_t scl) {
uint32_t port = self->scl->phys_port;
scl &= 0x01;
self->prev_sda = sda;
self->prev_scl = scl;
gpio_output_set((sda << self->sda->phys_port) | (scl << self->scl->phys_port),
((1 - sda) << self->sda->phys_port) | ((1 - scl) << self->scl->phys_port),
(1 << self->sda->phys_port) | (1 << self->scl->phys_port), 0);
gpio_output_set(scl << port, (1 - scl) << port, 1 << port, 0);
}
STATIC int mphal_i2c_get_sda(pyb_i2c_obj_t *self) {
@ -63,21 +63,21 @@ STATIC int mphal_i2c_get_sda(pyb_i2c_obj_t *self) {
}
STATIC void mphal_i2c_start(pyb_i2c_obj_t *self) {
mphal_i2c_set_sda_scl(self, 1, self->prev_scl);
mphal_i2c_set_sda(self, 1);
mphal_i2c_wait_a();
mphal_i2c_set_sda_scl(self, 1, 1);
mphal_i2c_set_scl(self, 1);
mphal_i2c_wait_a();
mphal_i2c_set_sda_scl(self, 0, 1);
mphal_i2c_set_sda(self, 0);
mphal_i2c_wait_a();
}
STATIC void mphal_i2c_stop(pyb_i2c_obj_t *self) {
mphal_i2c_wait_a();
mphal_i2c_set_sda_scl(self, 0, self->prev_scl);
mphal_i2c_set_sda(self, 0);
mphal_i2c_wait_a();
mphal_i2c_set_sda_scl(self, 0, 1);
mphal_i2c_set_scl(self, 1);
mphal_i2c_wait_a();
mphal_i2c_set_sda_scl(self, 1, 1);
mphal_i2c_set_sda(self, 1);
mphal_i2c_wait_a();
}
@ -102,25 +102,26 @@ STATIC void mphal_i2c_init(pyb_i2c_obj_t *self, uint32_t freq) {
GPIO_REG_WRITE(GPIO_ENABLE_ADDRESS,
GPIO_REG_READ(GPIO_ENABLE_ADDRESS) | (1 << scl->phys_port));
mphal_i2c_set_sda_scl(self, 1, 1);
mphal_i2c_set_scl(self, 1);
mphal_i2c_set_sda(self, 1);
ETS_GPIO_INTR_ENABLE();
//ETS_INTR_UNLOCK();
mphal_i2c_set_sda_scl(self, 1, 0);
mphal_i2c_set_scl(self, 0);
mphal_i2c_wait_a();
// when SCL = 0, toggle SDA to clear up
mphal_i2c_set_sda_scl(self, 0, 0);
mphal_i2c_set_sda(self, 0);
mphal_i2c_wait_a();
mphal_i2c_set_sda_scl(self, 1, 0);
mphal_i2c_set_sda(self, 1);
mphal_i2c_wait_a();
// set data_cnt to max value
for (uint8_t i = 0; i < 28; i++) {
mphal_i2c_set_sda_scl(self, 1, 0);
mphal_i2c_set_scl(self, 0);
mphal_i2c_wait_a();
mphal_i2c_set_sda_scl(self, 1, 1);
mphal_i2c_set_scl(self, 1);
mphal_i2c_wait_a();
}
@ -134,34 +135,32 @@ STATIC int mphal_i2c_write_byte(pyb_i2c_obj_t *self, uint8_t val) {
mphal_i2c_wait_a();
mphal_i2c_set_sda_scl(self, self->prev_sda, 0);
mphal_i2c_set_scl(self, 0);
mphal_i2c_wait_a();
for (i = 7; i >= 0; i--) {
dat = val >> i;
mphal_i2c_set_sda_scl(self, dat, 0);
mphal_i2c_set_sda(self, dat);
mphal_i2c_wait_a();
mphal_i2c_set_sda_scl(self, dat, 1);
mphal_i2c_set_scl(self, 1);
mphal_i2c_wait_a();
if (i == 0) {
mphal_i2c_wait_b();
}
mphal_i2c_set_sda_scl(self, dat, 0);
mphal_i2c_set_scl(self, 0);
mphal_i2c_wait_a();
}
mphal_i2c_set_sda_scl(self, self->prev_sda, 0);
mphal_i2c_set_sda(self, 1);
mphal_i2c_wait_a();
mphal_i2c_set_sda_scl(self, 1, 0);
mphal_i2c_wait_a();
mphal_i2c_set_sda_scl(self, 1, 1);
mphal_i2c_set_scl(self, 1);
mphal_i2c_wait_a();
int ret = mphal_i2c_get_sda(self);
mphal_i2c_wait_a();
mphal_i2c_set_sda_scl(self, 1, 0);
mphal_i2c_set_scl(self, 0);
mphal_i2c_wait_a();
return !ret;