Data Sheet

1030
Atmel | SMART SAM D21 [DATASHEET]
Atmel-42181G–SAM-D21_Datasheet–09/2015
// If higher priority interrupts exist, then disable so that the
// following two writes are atomic.
SERCOM - STATUS.reg = 0;
SERCOM - CTRLB.reg = 0;
// Re-enable interrupts if applicable.
Write CTRLB.ACKACT to 1 using the following sequence:
// If higher priority interrupts exist, then disable so that the
// following two writes are atomic.
SERCOM - STATUS.reg = 0;
SERCOM - CTRLB.reg = SERCOM_I2CS_CTRLB_ACKACT;
// Re-enable interrupts if applicable.
Otherwise, only write to CTRLB in the AMATCH or DRDY interrupts if it is to close
out a transaction.
When not closing a transaction, clear the AMATCH interrupt by writing a 1 to its bit
position instead of using CTRLB.CMD. The DRDY interrupt is automatically
cleared by reading/writing to the DATA register in smart mode. If not in smart
mode, DRDY should be cleared by writing a 1 to its bit position.
Code replacements examples:
Current:
SERCOM - CTRLB.reg |= SERCOM_I2CS_CTRLB_ACKACT;
Change to:
// If higher priority interrupts exist, then disable so that the
// following two writes are atomic.
SERCOM - STATUS.reg = 0;
SERCOM - CTRLB.reg = SERCOM_I2CS_CTRLB_ACKACT;
// Re-enable interrupts if applicable.
Current:
SERCOM - CTRLB.reg &= ~SERCOM_I2CS_CTRLB_ACKACT;
Change to:
// If higher priority interrupts exist, then disable so that the
// following two writes are atomic.
SERCOM - STATUS.reg = 0;
SERCOM - CTRLB.reg = 0;
// Re-enable interrupts if applicable.
Current: