SH7059 Datasheet, PDF (479/1042 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer

15. Serial Communication Interface (SCI)
Transmitting Serial Data (Synchronous Mode): Figure 15.18 shows a sample flowchart for transmitting serial data. The
procedure is as follows (the steps correspond to the numbers in the flowchart):
Initialization
Start of transmission
Read TDRE flag in SSR
TDRE = 1?
Yes
Write transmit data in TDR and
clear TDRE flag to 0 in SSR
All data transmitted?
Yes
Read TEND flag in SSR
1
1. SCI initialization: Set the TxD pin function
with the PFC.
2. SCI status check and transmit data write:
Read SSR, check that the TDRE flag is 1,
2 then write transmit data in TDR and clear
the TDRE flag to 0.
3. To continue transmitting serial data: After
No
checking that the TDRE flag is 1, indicating
that data can be written, write data in TDR,
then clear the TDRE flag to 0. When the
DMAC is activated by a transmit-data-empty
interrupt request (TXI) to write data in TDR,
the TDRE flag is checked and cleared
automatically.
Note: Do not write to SMR, SCR, BRR, or
SDCR between the start and the end of
a transmit operation. However, this does
No
not apply to operation 4.
3
No
TEND = 1?
Yes
Clear TE bit to 0 in SCR
4
End of transmission
Figure 15.18 Sample Flowchart for Serial Transmitting
Rev.3.00 Mar. 12, 2008 Page 389 of 948
REJ09B0177-0300