27.5.10 Client Control A


Bit	7	6	5	4	3	2	1	0
	DIEN	APIEN	PIEN			PMEN	SMEN	ENABLE
Access	R/W	R/W	R/W			R/W	R/W	R/W
Reset	0	0	0			0	0	0

Bit 7 – DIEN Data Interrupt Enable

Writing this bit to ‘1’ enables an interrupt on the Data Interrupt Flag (DIF) from the Client Status (TWIn.SSTATUS) register.

A TWI client data interrupt will only be generated if this bit, the DIF flag, and the Global Interrupt Enable (I) bit in the Status (CPU.SREG) register are all ‘1’.

Bit 6 – APIEN Address or Stop Interrupt Enable

Writing this bit to ‘1’ enables an interrupt on the Address or Stop Interrupt Flag (APIF) from the Client Status (TWIn.SSTATUS) register.

A TWI client address or stop interrupt will only be generated if this bit, the APIF flag, and the Global Interrupt Enable (I) bit in the Status (CPU.SREG) register are all ‘1’.

Note:

The client stop interrupt shares the interrupt flag and vector with the client address interrupt.
The Stop Interrupt Enable (PIEN) bit in the Client Control A (TWIn.SCTRLA) register must be written to ‘1’ for the APIF to be set on a Stop condition.
When the interrupt occurs, the Address or Stop (AP) bit in the Client Status (TWIn.SSTATUS) register will determine whether an address match or a Stop condition caused the interrupt.

Bit 5 – PIEN Stop Interrupt Enable

Writing this bit to ‘1’ allows the Address or Stop Interrupt Flag (APIF) in the Client Status (TWIn.SSTATUS) register to be set when a Stop condition occurs. The main clock frequency must be at least four times the SCL frequency to use this feature.

Bit 2 – PMEN Address Recognition Mode

If this bit is written to ‘1’, the client address match logic responds to all received addresses.

If this bit is written to ‘0’, the address match logic uses the Client Address (TWIn.SADDR) register to determine which address to recognize as the client’s address.

Bit 1 – SMEN Smart Mode Enable

Writing this bit to ‘1’ enables the client Smart mode. When the Smart mode is enabled, issuing a command by writing to the Command (SCMD) bit field in the Client Control B (TWIn.SCTRLB) register or accessing the Client Data (TWIn.SDATA) register resets the interrupt, and the operation continues. If the Smart mode is disabled, the client always waits for a new client command before continuing.

Bit 0 – ENABLE Enable TWI Client

Writing this bit to ‘1’ enables the TWI client.

Name:	SCTRLA
Offset:	0x09
Reset:	0x00
Property:	-