Analog Devices SHARC ADSP-214 Series, Hardware Reference Manual, Page: 1091 / 1192

ADSP-214xx SHARC Processor Hardware Reference A-265
Registers Reference
Interrupt Latch Register (TWIIRPTL)
The TWI interrupt source register (
TWIIRPTL
, shown in Figure A-153 and
described in Table A-144 ) contains information about functional areas
requiring servicing. Many of the bits serve as an indicator to further read
and service various status registers. After servicing the interrupt source
associated with a bit, the user must clear that interrupt source bit. All bits
are sticky and W1C.
Table A-143. TWIFIFOSTAT Register Bit Descriptions (RO)
Bit Name Description
1–0 TWITXS Transfer FIFO Status. These read-only bits indicate the num-
ber of valid data bytes in the FIFO buffer. The status is
updated with each FIFO buffer write using the peripheral data
bus or read access by the transmit shift register. Simultaneous
accesses are allowed.
00 = FIFO is empty. Either a single- or double-byte peripheral
write of the FIFO goes through immediately.
01 = FIFO contains one byte of data. A single byte peripheral
write of the FIFO goes through immediately. A double-byte
peripheral write waits until the FIFO is empty
11 = FIFO is full and contains two bytes of data.
10 = Illegal
3–2 TWIRXS Receive FIFO Status. These read-only bits indicate the num-
ber of valid data bytes in the receive FIFO buffer. The status is
updated with each FIFO buffer read using the peripheral data
bus or write access by the receive shift register. Simultaneous
accesses are allowed.
00 = FIFO is empty.
01 = FIFO contains one byte of data. A single-byte peripheral
read of the FIFO goes through immediately. A double-byte
peripheral read waits until the FIFO is full.
11 = FIFO is full and contains two bytes of data. Either a sin-
gle- or double-byte peripheral read of the FIFO is allowed.
10 = Illegal
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