HD643303x Hitachi, HD643303x Datasheet - Page 376

• Manufacturer Part Number: HD643303x
• Description: Hitachi Microcomputer
• Manufacturer: Hitachi

Receiving Serial Data: Figure 11-18 shows a sample flowchart for receiving serial data and
indicates the procedure to follow. When switching from asynchronous mode to synchronous
mode, make sure that the ORER, PER, and FER flags are cleared to 0. If the FER or PER flag is
set to 1 the RDRF flag will not be set and both transmitting and receiving will be disabled.
No
No
Read ORER flag in SSR
Read RDRF flag in SSR
Clear RE bit to 0 in SCR
RDRF flag to 0 in SSR
from RDR, and clear
Read receive data
Start receiving
ORER = 1?
RDRF = 1?
receiving?
Finished
Initialize
End
Figure 11-18 Sample Flowchart for Serial Receiving (1)
Yes
Yes
No
Yes
Error handling
1
2
4
5
3
361
1.
2., 3.
4.
5.
SCI initialization: the receive data function of
the RxD pin is selected automatically.
occurs, read the ORER flag in SSR, then after
executing the necessary error handling, clear
the ORER flag to 0. Neither transmitting nor
receiving can resume while the ORER flag
remains set to 1.
SCI status check and receive data read: read
SSR, check that the RDRF flag is set to 1,
then read receive data from RDR and clear
the RDRF flag to 0. Notification that the RDRF
flag has changed from 0 to 1 can also be
given by the RXI interrupt.
To continue receiving serial data: check the
RDRF flag, read RDR, and clear the RDRF
flag to 0 before the MSB (bit 7) of the current
frame is received.
Receive error handling: if a receive error