-/*!
- * Send START condition and select slave for write.
- *
- * \return true on success, false otherwise.
- */
-static bool twi_start_w(uint8_t slave_addr)
-{
- ASSERT(slave_addr < 8);
-
- /*
- * Loop on the select write sequence: when the eeprom is busy
- * writing previously sent data it will reply to the SLA_W
- * control byte with a NACK. In this case, we must
- * keep trying until the eeprom responds with an ACK.
- */
- while (twi_start())
- {
- TWDR = SLA_W | (slave_addr << 1);
- TWCR = BV(TWINT) | BV(TWEN);
- WAIT_TWI_READY;
-
- if (TW_STATUS == TW_MT_SLA_ACK)
- return true;
- else if (TW_STATUS != TW_MT_SLA_NACK)
- {
- DB(kprintf("!TW_MT_SLA_(N)ACK: %x\n", TWSR);)
- break;
- }
- }
-
- return false;
-}
-
-
-/*!
- * Send START condition and select slave for read.
- *
- * \return true on success, false otherwise.
- */
-static bool twi_start_r(uint8_t slave_addr)
-{
- ASSERT(slave_addr < 8);
-
- if (twi_start())
- {
- TWDR = SLA_R | (slave_addr << 1);
- TWCR = BV(TWINT) | BV(TWEN);
- WAIT_TWI_READY;
-
- if (TW_STATUS == TW_MR_SLA_ACK)
- return true;
-
- DB(kprintf("!TW_MR_SLA_ACK: %x\n", TWSR);)
- }
-
- return false;
-}
-
-
-/*!
- * Send STOP condition.
- */
-static void twi_stop(void)
-{
- TWCR = BV(TWINT) | BV(TWEN) | BV(TWSTO);
-}
-
-
-/*!
- * Send a sequence of bytes in master transmitter mode
- * to the selected slave device through the TWI bus.
- *
- * \return true on success, false on error.
- */
-static bool twi_send(const void *_buf, size_t count)
-{
- const uint8_t *buf = (const uint8_t *)_buf;
-
- while (count--)
- {
- TWDR = *buf++;
- TWCR = BV(TWINT) | BV(TWEN);
- WAIT_TWI_READY;
- if (TW_STATUS != TW_MT_DATA_ACK)
- {
- DB(kprintf("!TW_MT_DATA_ACK: %x\n", TWSR);)
- return false;
- }
- }