Renesas H8S/2111B 用户手册

Rev. 1.00, 05/04, page 269 of 544 

 

Yes

<End>

[1]

No

Initialization

Start reception

[2]

No

Yes

Read RDRF flag in SSR

[4]

[5]

Clear RE bit in SCR to 0

Error processing

(Continued below)

[3]

Read receive data in RDR and

clear RDRF flag in SSR to 0

No

Yes

ORER = 1

RDRF = 1

All data received?

Read ORER flag in SSR

<End>

Error processing

Overrun error processing

Clear ORER flag in SSR to 0

[3]

[1] SCI 

initialization:

 

The RxD pin is automatically 
designated as the receive data input 
pin.

[2]  [3]  Receive error processing:
 

If a receive error occurs, read the 
ORER flag in SSR, and after 
performing the appropriate error 
processing, clear the ORER flag to 0.  
Transfer cannot be resumed if the 
ORER flag is set to 1.

[4]  SCI status check and receive data 

read:

 

Read SSR and check that the RDRF 
flag is set to 1, then read the receive 
data in RDR and clear the RDRF flag 
to 0.

 

Transition of the RDRF flag from 0 to 
1 can also be identified by an RXI 
interrupt.

[5]   Serial reception continuation 

procedure:

 

Figure 12.20 shows a sample flowchart for simultaneous serial transmit and receive operations. 
After initializing the SCI, the following procedure should be used for simultaneous serial data 
transmit and receive operations. To switch from transmit mode to simultaneous transmit and 
receive mode, check that the SCI has finished transmission and the TDRE and TEND flags in SSR 
are set to 1, clear the TE bit in SCR to 0, and then set the TE and RE bits to 1 simultaneously with 
a single instruction. To switch from receive mode to simultaneous transmit and receive mode, 
check that the SCI has finished reception, and clear the RE bit to 0. Then after checking that the 
RDRF bit in SSR and receive error flags (ORER, FER, and PER) are cleared to 0, set the TE and 
RE bits to 1 simultaneously with a single instruction.