ADSP-214xx SHARC Processor Hardware Reference
20-11
UART Port Controller
(
UARTTHR
) initiates the transmit operation and reads from this address
return the
UARTRBR
register.
Note that data is transmitted and received by the least significant bit
(LSB) first (bit 0) followed by the most significant bits (MSBs).
Receive Buffer Registers (UARTRBR)
The receive operation uses the same data format as the transmit configura-
tion, except that the number of stop bits is always assumed to be 1. After
detection of the start bit, the received word is shifted into the receive shift
register (
UARTRSR
) at a baud rate of
PCLK
/(16 x Divisor). After the appro-
priate number of bits (including stop bit) is received, the data and any
status are updated and the
UARTRSR
register is transferred to the UART
receive buffer register (
UARTRBR
), shown in
. After the transfer
of the received word to the
UARTRBR
buffer and the appropriate synchroni-
zation delay, the data ready status flag (
UARTDR
) is updated.
A sampling clock equal to 16 times the baud rate samples the data as close
to the midpoint of the bit as possible. Because the internal sample clock
may not exactly match the asynchronous receive data rate, the sampling
point drifts from the center of each bit. The sampling point is synchro-
nized again with each start bit, so the error accumulates only over the
Figure 20-3. UART Transmit Holding Register (Packing Enabled)
TX9D0
TX9D1
Zero-Filled
Zero-Filled
0
9
8
3
7
5
6
4
2
1
14
12
11 10
1
3
15
3
1
3
0
29 2
8
27 26
25 24
2
3
22
21 20 19 1
8
17 16
Higher Byte (2
3
–16)
Lower Byte (7–0)
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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...
Страница 264: ...Programming Models 3 134 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
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Страница 296: ...Programming Model 5 6 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
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 714: ...Programming Model 19 10 ADSP 214xx SHARC Processor Hardware Reference www BDTIC com ADI...
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...