diff options
Diffstat (limited to 'libraries/Wire/utility/twi.c')
| -rw-r--r-- | libraries/Wire/utility/twi.c | 30 |
1 files changed, 24 insertions, 6 deletions
diff --git a/libraries/Wire/utility/twi.c b/libraries/Wire/utility/twi.c index 201d7d1..2af0597 100644 --- a/libraries/Wire/utility/twi.c +++ b/libraries/Wire/utility/twi.c @@ -91,6 +91,22 @@ void twi_init(void) } /* + * Function twi_disable + * Desc disables twi pins + * Input none + * Output none + */ +void twi_disable(void) +{ + // disable twi module, acks, and twi interrupt + TWCR &= ~(_BV(TWEN) | _BV(TWIE) | _BV(TWEA)); + + // deactivate internal pullups for twi. + digitalWrite(SDA, 0); + digitalWrite(SCL, 0); +} + +/* * Function twi_slaveInit * Desc sets slave address and enables interrupt * Input none @@ -151,7 +167,9 @@ uint8_t twi_readFrom(uint8_t address, uint8_t* data, uint8_t length, uint8_t sen // up. Also, don't enable the START interrupt. There may be one pending from the // repeated start that we sent outselves, and that would really confuse things. twi_inRepStart = false; // remember, we're dealing with an ASYNC ISR - TWDR = twi_slarw; + do { + TWDR = twi_slarw; + } while(TWCR & _BV(TWWC)); TWCR = _BV(TWINT) | _BV(TWEA) | _BV(TWEN) | _BV(TWIE); // enable INTs, but not START } else @@ -231,7 +249,9 @@ uint8_t twi_writeTo(uint8_t address, uint8_t* data, uint8_t length, uint8_t wait // up. Also, don't enable the START interrupt. There may be one pending from the // repeated start that we sent outselves, and that would really confuse things. twi_inRepStart = false; // remember, we're dealing with an ASYNC ISR - TWDR = twi_slarw; + do { + TWDR = twi_slarw; + } while(TWCR & _BV(TWWC)); TWCR = _BV(TWINT) | _BV(TWEA) | _BV(TWEN) | _BV(TWIE); // enable INTs, but not START } else @@ -460,18 +480,16 @@ ISR(TWI_vect) } break; case TW_SR_STOP: // stop or repeated start condition received + // ack future responses and leave slave receiver state + twi_releaseBus(); // put a null char after data if there's room if(twi_rxBufferIndex < TWI_BUFFER_LENGTH){ twi_rxBuffer[twi_rxBufferIndex] = '\0'; } - // sends ack and stops interface for clock stretching - twi_stop(); // callback to user defined callback twi_onSlaveReceive(twi_rxBuffer, twi_rxBufferIndex); // since we submit rx buffer to "wire" library, we can reset it twi_rxBufferIndex = 0; - // ack future responses and leave slave receiver state - twi_releaseBus(); break; case TW_SR_DATA_NACK: // data received, returned nack case TW_SR_GCALL_DATA_NACK: // data received generally, returned nack |