HD64F3039F18 Datasheet, PDF (388/710 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8 Family / H8/300H Series

Section 11 Serial Communication Interface
Transmitting Serial Data (Asynchronous Mode): Figure 11.5 shows a sample flowchart for
transmitting serial data and indicates the procedure to follow.
1
Initialize
Start transmitting
Read TDRE flag in SSR
2
No
TDRE = 1?
Yes
Write transmit data
in TDR and clear TDRE
flag to 0 in SSR
1. SCI initialization: the transmit data output function
of the TxD pin is selected automatically.
2. SCI status check and transmit data write: read SSR,
check that the TDRE flag is 1, then write transmit data
in TDR and clear the TDRE flag to 0.
3. To continue transmitting serial data: after checking
that the TDRE flag is 1, indicating that data can be
written, 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 1 and clear the DR bit to 0
(DDR and DR are I/O port registers), then clear the
TE bit to 0 in SCR.
All data
transmitted?
Yes
No
3
Read TEND flag in SSR
TEND = 1?
Yes
Output break
signal?
Yes
No
No
4
Clear DR bit to 0,
set DDR bit to 1
Clear TE bit to 0 in SCR
End
Figure 11.5 Sample Flowchart for Transmitting Serial Data
Rev.3.00 Mar. 26, 2007 Page 364 of 682
REJ09B0353-0300