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extmod/machine_i2c: Fix I2C reading by sending ack/nack at end of byte.

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This commit is contained in:
Damien George 2016-04-12 15:46:13 +01:00
parent 73bc0c24ab
commit 9314b2df4f
1 changed files with 11 additions and 4 deletions
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15
extmod/machine_i2c.c
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@ -134,6 +134,7 @@ STATIC void mp_hal_i2c_write(machine_i2c_obj_t *self, uint8_t addr, uint8_t *dat
goto er; goto er;
} }
} }
mp_hal_i2c_stop(self);
return; return;
er: er:
@ -141,7 +142,7 @@ er:
nlr_raise(mp_obj_new_exception_msg(&mp_type_OSError, "I2C bus error")); nlr_raise(mp_obj_new_exception_msg(&mp_type_OSError, "I2C bus error"));
} }
STATIC int mp_hal_i2c_read_byte(machine_i2c_obj_t *self, uint8_t *val) { STATIC int mp_hal_i2c_read_byte(machine_i2c_obj_t *self, uint8_t *val, int nack) {
mp_hal_i2c_delay(self); mp_hal_i2c_delay(self);
mp_hal_i2c_scl_low(self); mp_hal_i2c_scl_low(self);
mp_hal_i2c_delay(self); mp_hal_i2c_delay(self);
@ -156,10 +157,15 @@ STATIC int mp_hal_i2c_read_byte(machine_i2c_obj_t *self, uint8_t *val) {
} }
*val = data; *val = data;
// send ack/nack bit
if (!nack) {
mp_hal_i2c_sda_low(self);
}
mp_hal_i2c_delay(self);
mp_hal_i2c_scl_release(self); mp_hal_i2c_scl_release(self);
mp_hal_i2c_delay(self); mp_hal_i2c_delay(self);
mp_hal_i2c_scl_low(self); mp_hal_i2c_scl_low(self);
mp_hal_i2c_delay(self); mp_hal_i2c_sda_release(self);
return 1; // success return 1; // success
} }
@ -170,10 +176,11 @@ STATIC void mp_hal_i2c_read(machine_i2c_obj_t *self, uint8_t addr, uint8_t *data
goto er; goto er;
} }
while (len--) { while (len--) {
if (!mp_hal_i2c_read_byte(self, data++)) { if (!mp_hal_i2c_read_byte(self, data++, len == 0)) {
goto er; goto er;
} }
} }
mp_hal_i2c_stop(self);
return; return;
er: er:
@ -254,7 +261,7 @@ STATIC mp_obj_t machine_i2c_readinto(mp_obj_t self_in, mp_obj_t buf_in) {
// do the read // do the read
uint8_t *dest = bufinfo.buf; uint8_t *dest = bufinfo.buf;
while (bufinfo.len--) { while (bufinfo.len--) {
if (!mp_hal_i2c_read_byte(self, dest++)) { if (!mp_hal_i2c_read_byte(self, dest++, bufinfo.len == 0)) {
nlr_raise(mp_obj_new_exception_msg(&mp_type_OSError, "I2C bus error")); nlr_raise(mp_obj_new_exception_msg(&mp_type_OSError, "I2C bus error"));
} }
} }