diff options
| -rw-r--r-- | src/i2c_software.c | 22 |
1 files changed, 12 insertions, 10 deletions
diff --git a/src/i2c_software.c b/src/i2c_software.c index 77da9447..805cef2d 100644 --- a/src/i2c_software.c +++ b/src/i2c_software.c @@ -65,9 +65,7 @@ i2c_delay(uint32_t ticks) static void i2c_software_send_ack(struct i2c_software *is, const uint8_t ack) { - if (ack) { - gpio_in_reset(is->sda_in, 1); - } else { + if (!ack) { gpio_out_reset(is->sda_out, 0); } i2c_delay(is->ticks); @@ -77,27 +75,32 @@ i2c_software_send_ack(struct i2c_software *is, const uint8_t ack) } static uint8_t -i2c_software_read_ack(struct i2c_software *is) +i2c_software_read_ack(struct i2c_software *is, uint_fast8_t state) { uint8_t nack = 0; - gpio_in_reset(is->sda_in, 1); + if (state == 0) + gpio_in_reset(is->sda_in, 1); i2c_delay(is->ticks); gpio_in_reset(is->scl_in, 1); nack = gpio_in_read(is->sda_in); i2c_delay(is->ticks); gpio_out_reset(is->scl_out, 0); - gpio_in_reset(is->sda_in, 1); return nack; } static int i2c_software_send_byte(struct i2c_software *is, uint8_t b) { + uint_fast8_t state = 2; for (uint_fast8_t i = 0; i < 8; i++) { if (b & 0x80) { - gpio_in_reset(is->sda_in, 1); + if (state != 1) + gpio_in_reset(is->sda_in, 1); + state = 1; } else { - gpio_out_reset(is->sda_out, 0); + if (state > 0) + gpio_out_reset(is->sda_out, 0); + state = 0; } b <<= 1; i2c_delay(is->ticks); @@ -106,7 +109,7 @@ i2c_software_send_byte(struct i2c_software *is, uint8_t b) gpio_out_reset(is->scl_out, 0); } - if (i2c_software_read_ack(is)) { + if (i2c_software_read_ack(is, state)) { return I2C_BUS_NACK; } @@ -126,7 +129,6 @@ i2c_software_read_byte(struct i2c_software *is, uint8_t remaining) b |= gpio_in_read(is->sda_in); gpio_out_reset(is->scl_out, 0); } - gpio_in_reset(is->sda_in, 1); i2c_software_send_ack(is, remaining == 0); return b; } |