381
0
1
1
1
0/1
0
1
TDRE
TEND
Parity
bit
Parity
bit
Serial
data
Start
bit
Data
Stop
bit
Start
bit
Data
Stop
bit
Idle (mark)
state
TXI
request
TXI interrupt
handler writes
data in TDR
and clears
TDRE to 0
TXI
request
TEI request
1 frame
D
0
D
1
D
7
D
0
D
1
D
7
0/1
Figure 13.6 Example of SCI Transmit Operation in Asynchronous Mode (8-Bit Data with
Parity and One Stop Bit)
Receiving Serial Data (Asynchronous Mode): Figure 13.7 shows a sample flowchart for
receiving serial data. The procedure for receiving serial data is listed below.
1. SCI initialization: select the RxD pin function with the PFC.
2. Receive error handling and break detection: if a receive error occurs, read the ORER, PER and
FER bits in SSR to identify the error. After executing the necessary error handling, clear
ORER, PER, and FER all to 0. Receiving cannot resume if ORER, PER, or FER remains set to
1. When a framing error occurs, the RxD pin can be read to detect the break state.
3. SCI status check and receive data read: read the serial status register (SR), check that RDRF is
set to 1, then read receive data from the receive data register (RDR) and clear RDRF to 0. The
RXI interrupt can also be used to determine if the RDRF bit has changed from 0 to 1.
4. To continue receiving serial data: read RDRF and RDR, and clear RDRF to 0 before the stop
bit of the current frame is received. If the DMAC is started by a receive-data-full interrupt
(RXI) to read RDR, the RDRF bit is cleared automatically, so this step is unnecessary.
Содержание HD6417032
Страница 21: ......
Страница 35: ...xiv ...
Страница 85: ...50 ...
Страница 101: ...66 ...
Страница 129: ...94 ...
Страница 135: ...100 ...
Страница 343: ...308 ...
Страница 369: ...334 ...
Страница 383: ...348 ...
Страница 475: ...440 ...
Страница 525: ...490 CK RAS CAS TRp TRc TRcc tRASD1 tRASD2 tCASD3 tCASD2 TRr tCSR Figure 20 18 Self Refresh ...
Страница 578: ...543 CK RAS CAS TRp TRc TRcc tRASD1 tRASD2 tCASD3 tCASD2 TRr tCSR Figure 20 62 Self Refresh ...
Страница 689: ...654 ...