HD6412320 RENESAS [Renesas Technology Corp], HD6412320 Datasheet - Page 680

• Manufacturer Part Number: HD6412320
• Description: Renesas 16-Bit Single-Chip Microcomputer H8S Family H8S-2300 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

Section 14 Serial Communication Interface (SCI)
Serial data transmission (synchronous mode): Figure 14.16 shows a sample flowchart for serial
transmission.
The following procedure should be used for serial data transmission.
Rev.6.00 Sep. 27, 2007 Page 650 of 1268
REJ09B0220-0600
Note: * The DMAC is not supported in the H8S/2321.
Write transmit data to TDR and
clear TDRE flag in SSR to 0
Read TDRE flag in SSR
Read TEND flag in SSR
Clear TE bit in SCR to 0
Start of transmission
All data transmitted?
Initialization
TDRE = 1?
TEND = 1?
<End>
Figure 14.16 Sample Serial Transmission Flowchart
Yes
Yes
Yes
No
No
No
[3]
[2]
[1]
[1] SCI initialization:
[2] SCI status check and transmit data
[3] Serial transmission continuation
The TxD pin is automatically
designated as the transmit data output
pin.
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.
procedure:
To continue serial transmission, be
sure to 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 DMAC* or
DTC is activated by a transmit-data-
empty interrupt (TXI) request and data
is written to TDR.