h8s-2138 Renesas Electronics Corporation., h8s-2138 Datasheet - Page 477

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

Serial Data Transmission (Asynchronous Mode): Figure 15.5 shows a sample flowchart for
serial transmission.
The following procedure should be used for serial data transmission.
and clear TDRE flag in SSR to 0
Write transmit data to TDR
Read TDRE flag in SSR
Read TEND flag in SSR
Clear TE bit in SCR to 0
All data transmitted?
Clear DR to 0 and
Start transmission
Break output?
set DDR to 1
Initialization
TDRE = 1?
TEND = 1?
Figure 15.5 Sample Serial Transmission Flowchart
<End>
Yes
Yes
Yes
Yes
No
No
No
No
Section 15 Serial Communication Interface (SCI, IrDA)
[1]
[2]
[3]
[4]
[1] SCI initialization:
[2] SCI status check and transmit data
[3] Serial transmission continuation
[4] Break output at the end of serial
Rev. 4.00 Jun 06, 2006 page 423 of 1004
The TxD pin is automatically
designated as the transmit data
output pin.
After the TE bit is set to 1, one
frame of 1s is output and
transmission is enabled.
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,
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.
transmission:
To output a break in serial
transmission, set DDR for the port
corresponding to the TxD pin to 1,
clear DR to 0, then clear the TE bit
in SCR to 0.
REJ09B0301-0400