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extmod/machine_i2c: Make the clock stretching timeout configurable

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Radomir Dopieralski 2016-10-22 22:44:19 +02:00 committed by Damien George
parent b188d6e9db
commit 702928915c
1 changed files with 5 additions and 5 deletions
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10
extmod/machine_i2c.c
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@ -34,12 +34,10 @@
#if MICROPY_PY_MACHINE_I2C
// Clock stretching limit, so that we don't get stuck.
#define I2C_STRETCH_LIMIT 255
typedef struct _machine_i2c_obj_t {
mp_obj_base_t base;
uint32_t us_delay;
uint32_t us_timeout;
mp_hal_pin_obj_t scl;
mp_hal_pin_obj_t sda;
} machine_i2c_obj_t;
@ -58,7 +56,7 @@ STATIC void mp_hal_i2c_scl_release(machine_i2c_obj_t *self) {
mp_hal_pin_od_high(self->scl);
mp_hal_i2c_delay(self);
// For clock stretching, wait for the SCL pin to be released, with timeout.
for (int count = I2C_STRETCH_LIMIT; mp_hal_pin_read(self->scl) == 0 && count; --count) {
for (uint32_t count = self->us_timeout; mp_hal_pin_read(self->scl) == 0 && count; --count) {
mp_hal_delay_us_fast(1);
}
}
@ -237,16 +235,18 @@ STATIC void mp_hal_i2c_read(machine_i2c_obj_t *self, uint8_t addr, uint8_t *dest
// MicroPython bindings for I2C
STATIC void machine_i2c_obj_init_helper(machine_i2c_obj_t *self, mp_uint_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
enum { ARG_scl, ARG_sda, ARG_freq };
enum { ARG_scl, ARG_sda, ARG_freq, ARG_timeout };
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_scl, MP_ARG_REQUIRED | MP_ARG_OBJ },
{ MP_QSTR_sda, MP_ARG_REQUIRED | MP_ARG_OBJ },
{ MP_QSTR_freq, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 400000} },
{ MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 255} },
};
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
self->scl = mp_hal_get_pin_obj(args[ARG_scl].u_obj);
self->sda = mp_hal_get_pin_obj(args[ARG_sda].u_obj);
self->us_timeout = args[ARG_timeout].u_int;
mp_hal_i2c_init(self, args[ARG_freq].u_int);
}