HD64336901G Renesas Technology, HD64336901G Datasheet - Page 232

• Manufacturer Part Number: HD64336901G
• Description: (HD64xxx Series) 16-BIT MICROCONTROLLER
• Manufacturer: Renesas Technology

14.4.3
Figure 14.6 shows an example of operation for transmission in asynchronous mode. In
transmission, SCI3 operates as described below.
1. SCI3 monitors the TDRE flag in SSR. If the flag is cleared to 0, SCI3 recognizes that data has
2. After transferring data from TDR to TSR, SCI3 sets the TDRE flag to 1 and starts
3. SCI3 checks the TDRE flag at the timing for sending the stop bit.
4. If the TDRE flag is 0, the data is transferred from TDR to TSR, the stop bit is sent, and then
5. If the TDRE flag is 1, the TEND flag in SSR is set to 1, the stop bit is sent, and then the “mark
6.
Rev. 1.00, 11/03, page 204 of 376
been written to TDR, and transfers the data from TDR to TSR.
transmission. If the TIE bit is set to 1 at this time, a TXI interrupt request is generated.
Continuous transmission is possible because the TXI interrupt routine writes next transmit data
to TDR before transmission of the current transmit data has been completed.
serial transmission of the next frame is started.
state” is entered, in which 1 is output. If the TEIE bit in SCR3 is set to 1 at this time, a TEI
interrupt request is generated.
Figure 14.7 shows a sample flowchart for transmission in asynchronous mode.
Serial
data
TDRE
TEND
LSI
operation
User
processing
Data Transmission
Figure 14.6 Example of SCI3 Transmission in Asynchronous Mode
TXI interrupt
request
generated
1
Start
bit
0
D0
D1
TDRE flag
cleared to 0
Data written
to TDR
Transmit
1 frame
(8-Bit Data, Parity, One Stop Bit)
data
D7
Parity
0/1
bit
TXI interrupt request generated
Stop
bit
1
Start
bit
0
D0
1 frame
D1
Transmit
data
D7
Parity
0/1
bit
TEI interrupt request
generated
Stop
bit
1
Mark
state
1