Client Control B

Name:
SCTRLB
Offset:
0x0A
Reset:
0x00
Access:
-
Bit76543210
ACKACTSCMD[1:0]
AccessR/WR/WR/W
Reset000

Bit 2 – ACKACT: Acknowledge Action

Acknowledge Action

The ACKACT(1) bit represents the behavior of the TWI client under certain conditions defined by the bus protocol state and the software interaction. If the Smart Mode Enable (SMEN) bit in the Client Control A (TWIn.SCTRLA) register is set to ‘1’, the acknowledge action is performed when the Client Data (TWIn.SDATA) register is read. Otherwise a command must be written to the Command (SCMD) bit field in the Client Control B (TWIn.SCTRLB) register.

The acknowledge action is not performed when the Client Data (TWIn.SDATA) register is written since the client is sending data.

ValueNameDescription
0 ACK Send ACK
1 NACK Send NACK

Bits 1:0 – SCMD[1:0]: Command

Command

The SCMD(1) bit field is a strobe. This bit field is always read as ‘0’.

Writing to this bit field triggers a client operation as defined by the table below.

Table 1. Command Settings
Value Name DIR Description
0x0 NOACT X No action
0x1 X Reserved
0x2 COMPTRANS W Execute Acknowledge Action succeeded by waiting for any Start (S/Sr) condition Used to complete a transaction
R Wait for any Start (S/Sr) condition
0x3 RESPONSE W Execute Acknowledge Action succeeded by the reception of the next byte
R Used in response to an address interrupt (APIF): Execute Acknowledge Action succeeded by client data interrupt.
Used in response to a data interrupt (DIF): Execute a byte read operation followed by Acknowledge Action.
Note: 1. The ACKACT bit and the SCMD bit field can be written simultaneously. The ACKACT will be updated before the command is triggered.