HD64F3039F18 Datasheet, PDF (395/710 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8 Family / H8/300H Series

Section 11 Serial Communication Interface
Transmitting and Receiving Data
Transmitting Multiprocessor Serial Data: Figure 11.10 shows a sample flowchart for
transmitting multiprocessor serial data and indicates the procedure to follow.
Initialize
1 1. SCI initialization: the transmit data
output function of the TxD pin is
Start transmitting
selected automatically.
2. SCI status check and transmit data
write: read SSR, check that the TDRE
Read TDRE flag in SSR
2
flag is 1, then write transmit
data in TDR. Also set the MPBT flag to
0 or 1 in SSR. Finally, clear the TDRE
TDRE = 1?
No
flag to 0.
3. To continue transmitting serial data:
after checking that the TDRE flag is 1,
Yes
indicating that data can be written,
Write transmit data in
TDR and set MPBT bit in SSR
write data in TDR, then clear the TDRE
flag to 0.
4. To output a break signal at the end of
serial transmission: set the DDR bit to
Clear TDRE flag to 0
1 and clear the DR bit to 0 (DDR and
DR are I/O port registers), then clear
All data transmitted?
No
3
the TE bit to 0 in SCR.
Yes
Read TEND flag in SSR
No
TEND = 1?
Yes
Output break signal?
No
4
Yes
Clear DR bit to 0, set DDR bit to 1
Clear TE bit to 0 in SCR
End
Figure 11.10 Sample Flowchart for Transmitting Multiprocessor Serial Data
Rev.3.00 Mar. 26, 2007 Page 371 of 682
REJ09B0353-0300