h8s-2138 Renesas Electronics Corporation., h8s-2138 Datasheet - Page 495

• Manufacturer Part Number: h8s-2138
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

Serial Data Transmission (Synchronous Mode): Figure 15.16 shows a sample flowchart for
serial transmission.
The following procedure should be used for serial data transmission.
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
All data transmitted?
Start transmission
Initialization
TDRE = 1?
TEND = 1?
<End>
Figure 15.16 Sample Serial Transmission Flowchart
Yes
Yes
Yes
No
No
No
Section 15 Serial Communication Interface (SCI, IrDA)
[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 DTC is
activated by a transmit-data-empty
interrupt (TXI) request and data is
written to TDR.
Rev. 4.00 Jun 06, 2006 page 441 of 1004
REJ09B0301-0400