SH7046 Datasheet, PDF (390/611 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family/SH7046 Series

Section 12 Serial Communication Interface (SCI)
Initialization
[1]
Start transmission
Read TDRE flag in SSR
[2]
No
TDRE = 1
Yes
Write transmit data to TDR
and clear TDRE flag in SSR to 0
All data transmitted?
Yes
Read TEND flag in SSR
No
[3]
TEND = 1
Yes
Break output?
Yes
Clear DR to 0
No
No
[4]
[1] SCI initialization:
Set the TxD pin using the PFC.
After the TE bit is set to 1, 1 is
output for one frame, and
transmission is enabled. However,
data is not transmitted.
[2] SCI status check and transmit data
write:
Read SSR and check that the
TDRE flag is set to 1, then write
transmit data to TDR and clear the
TDRE flag to 0.
[3] Serial transmission continuation
procedure:
To continue serial transmission,
read 1 from the TDRE flag to
confirm that writing is possible, then
write data to TDR, and then clear
the TDRE flag to 0. Checking and
clearing of the TDRE flag is
automatic when the DTC is
activated by a transmit data empty
interrupt (TXI) request, and data is
written to TDR.
[4] Break output at the end of serial
transmission:
To output a break in serial
transmission, first clear the port
data register (DR) to 0, then clear
the TE bit to 0 in SCR and use the
PFC to select the TxD pin as an
output port.
Clear TE bit in SCR to 0;
select the TxD pin
as an output port with the PFC
<End>
Figure 12.7 Sample Serial Transmission Flowchart
Rev. 4.00 Dec 05, 2005 page 346 of 564
REJ09B0270-0400