h8s-2111b Renesas Electronics Corporation., h8s-2111b Datasheet - Page 290

• Manufacturer Part Number: h8s-2111b
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family / H8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

12.4.6
Figure 12.8 shows an example of the operation for reception in asynchronous mode. In serial
reception, the SCI operates as described below.
1. The SCI monitors the communication line, and if a start bit is detected, performs internal
2. If an overrun error (when reception of the next data is completed while the RDRF flag in SSR
3. If a parity error is detected, the PER bit in SSR is set to 1 and receive data is transferred to
4. If a framing error (when the stop bit is 0) is detected, the FER bit in SSR is set to 1 and receive
5. If reception finishes successfully, the RDRF bit in SSR is set to 1, and receive data is
Table 12.9 shows the states of the SSR status flags and receive data handling when a receive error
is detected. If a receive error is detected, the RDRF flag retains its state before receiving data.
Reception cannot be resumed while a receive error flag is set to 1. Accordingly, clear the ORER,
FER, PER, and RDRF bits to 0 before resuming reception. Figure 12.9 shows a sample flow chart
for serial data reception.
Rev. 1.00, 05/04, page 256 of 544
synchronization, receives receive data in RSR, and checks the parity bit and stop bit.
is still set to 1) occurs, the ORER bit in SSR is set to 1. If the RIE bit in SCR is set to 1 at this
time, an ERI interrupt request is generated. Receive data is not transferred to RDR. The RDRF
flag remains to be set to 1.
RDR. If the RIE bit in SCR is set to 1 at this time, an ERI interrupt request is generated.
data is transferred to RDR. If the RIE bit in SCR is set to 1 at this time, an ERI interrupt
request is generated.
transferred to RDR. If the RIE bit in SCR is set to 1 at this time, an RXI interrupt request is
generated. Because the RXI interrupt routine reads the receive data transferred to RDR before
reception of the next receive data has finished, continuous reception can be enabled.
RDRF
FER
Serial Data Reception (Asynchronous Mode)
1
Figure 12.8 Example of SCI Receive Operation in Asynchronous Mode
Start
bit
0
D0
(Example with 8-Bit Data, Parity, One Stop Bit)
D1
1 frame
Data
D7
RXI interrupt
request
generated
Parity
bit
0/1
Stop
bit
1
Start
bit
0
RDR data read and RDRF
flag cleared to 0 in RXI
interrupt handling routine
D0
D1
Data
D7
Parity
bit
0/1
ERI interrupt request
generated by framing
error
Stop
bit
0
Idle state
(mark state)
1