Hitachi H8/3692 ユーザーズマニュアル

Rev. 1.0, 07/01, page 209 of 372

Yes

No

Start transmission/reception

[3]

Error processing

[4]

Read receive data in RDR

Yes

No

OER = 1

All data received?

[1]

Read TDRE flag in SSR

No

Yes

TDRE = 1

Write transmit data to TDR

No

Yes

RDRF = 1

Read ORER flag in SSR

Read RDRF flag in SSR

Clear TE and RE bits in SCR to 0

[1]

Read SSR and check that the TDRE 
flag is set to 1, then write transmit 
data to TDR.

        When data is written to TDR, the 

TDRE flag is automatically cleared to 
0.

[2]

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

        When data is read from RDR, the 

RDRF flag is automatically cleared to 
0.

[3]

To continue serial transmission/ 
reception, before the MSB (bit 7) of 
the current frame is received, read the 
RDRF flag, read RDR.  Also, before 
the MSB (bit 7) of the current frame is 
transmitted, read 1 from the TDRE 
flag to confirm that writing is possible.  
Then write data to TDR.

        When data is written to TDR, the 

TDRE flag is automatically cleared to 
0. When data is read from RDR, the 
RDRF flag is automatically cleared to 
0.

[4]

If an overrun error occurs, read the 
OER flag in SSR, and after 
performing the appropriate error 
processing, clear the OER flag to 0.  
Transmission/reception cannot be 
resumed if the OER flag is set to 1.

       For overrun error processing, see 

figure 14-13.

End

[2]