Data Transfer
21-12
ADSP-214xx SHARC Processor Hardware Reference
Data Transfer
The TWI uses its transmit and receive buffers for data transfer (no DMA
capability). These buffers are described in the following sections.
Data Buffers
The TWI has two data buffer FIFOs, which are described in the following
sections.
8-Bit Transmit FIFO Register
The TWI 8-bit transmit FIFO register (
TXTWI8
) shown in
holds an 8-bit data value written into the FIFO buffer. Transmit data is
entered into the corresponding transmit buffer in a first-in, first-out order.
Although peripheral bus writes are 32 bits, a write access to the
TXTWI8
register adds only one transmit data byte to the FIFO buffer. With each
access, the transmit status (
TWITXS
) field in the
TWIFIFOSTAT
register is
updated. If an access is performed while the FIFO buffer is full, the core
waits until there is at least one byte space in the transmit FIFO buffer and
then completes the write access.
16-Bit Transmit FIFO Register
The TWI 16-bit FIFO transmit register (
TXTWI16
holds a 16-bit data value written into the FIFO buffer. Although periph-
eral bus writes are 32 bits, a write access to the
TXTWI16
register adds only
two transmit data bytes to the FIFO buffer. To reduce interrupt output
Figure 21-7. 8-Bit Transmit FIFO Register
XMTDATA
8
(7–0)
Transmit FIFO
8
-Bit
Data
0
9
8
3
7
5
6
4
2
1
14
12
11 10
1
3
15
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Содержание SHARC ADSP-214 Series
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Страница 72: ...Notation Conventions lxxii ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 130: ...Programming Model 2 52 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
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Страница 396: ...Effect Latency 7 28 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 520: ...Programming Model 10 62 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 616: ...Debug Features 14 22 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
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Страница 1132: ...Register Listing A 306 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
Страница 1192: ...Index I 34 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...