Two Wire Interface Registers
A-134 ADSP-21368 SHARC Processor Hardware Reference
Table A-56. Slave Mode Control Register Bit Descriptions
Bit Name Description
0 TWISEN Slave Enable.
0 = The slave is not enabled. No attempt is made to identify a
valid address. If cleared during a valid transfer, clock stretching
ceases, the serial data line is released and the current byte is not
acknowledged.
1 = The slave is enabled. Enabling slave and master modes of
operation concurrently is allowed.
1 TWISLEN Slave Address Length.
0 = Address is a 7-bit address
1= Reserved. Setting this bit to 1 causes unpredictable behavior.
2 TWIDVAL Slave Transmit Data Valid.
0 = Data in the transmit FIFO is for master mode transmits and
is not allowed to be used during a slave transmit, and the transmit
FIFO is treated as if it is empty.
1 = Data in the transmit FIFO is available for a slave transmis-
sion.
3 TWINAK Not Acknowledged.
0 = Slave receive transfer generates an ACK at the conclusion of a
data transfer.
1 = Slave receive transfer generates a data NAK at the conclusion
of a data transfer. The slave is still considered to be addressed.
4 TWIGCE General Call Enable. General call address detection is available
only when slave mode is enabled.
0 = General call address matching is not enabled
1 = General call address matching is enabled. Regardless of the
selected address length of slave address, a general call slave receive
transfer is accepted. All status and interrupt source bits associated
with transfers are updated.