HD64F3039F18 Datasheet, PDF (404/710 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8 Family / H8/300H Series

Section 11 Serial Communication Interface
Receiving Serial Data (Synchronous Mode): 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.
Initialize
1
1. SCI initialization: the receive data function of
the RxD pin is selected automatically.
2., 3. Receive error handling: if a receive error
Start receiving
occurs, read the ORER flag in SSR, then after
executing the necessary error handling, clear
the ORER flag to 0. Neither transmitting nor
Read ORER flag in SSR
2
receiving can resume while the ORER flag
remains set to 1.
4. SCI status check and receive data read: read
ORER = 1?
Yes
3
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
No
Error handling
flag has changed from 0 to 1 can also be
(continued on next page) ^{given by the RXI interrupt.}
5. To continue receiving serial data: check the
Read RDRF flag in SSR
4
RDRF flag, read RDR, and clear the RDRF
flag to 0 before the MSB (bit 7) of the current
frame is received.
No
RDRF = 1?
Yes
Read receive data
from RDR, and clear
RDRF flag to 0 in SSR
No
Finished
receiving?
5
Yes
Clear RE bit to 0 in SCR
End
Figure 11.18 Sample Flowchart for Serial Receiving (1)
Rev.3.00 Mar. 26, 2007 Page 380 of 682
REJ09B0353-0300