r4f2456 Renesas Electronics Corporation., r4f2456 Datasheet - Page 910

• Manufacturer Part Number: r4f2456
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2400 Series
• Manufacturer: Renesas Electronics Corporation.

Section 15 Serial Communication Interface (SCI, IrDA)
Rev. 1.00 Sep. 19, 2008 Page 880 of 1342
REJ09B0467-0100
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 15.17 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.