r4f2426 Renesas Electronics Corporation., r4f2426 Datasheet - Page 901

• Manufacturer Part Number: r4f2426
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2400 Series
• Manufacturer: Renesas Electronics Corporation.

15.4.4
Before transmitting and receiving data, you should first clear the TE and RE bits in SCR to 0, then
initialize the SCI as shown in figure 15.5. When the operating mode, transfer format, etc., is
changed, the TE and RE bits must be cleared to 0 before making the change. When the TE bit is
cleared to 0, the TDRE flag is set to 1. Note that clearing the RE bit to 0 does not initialize the
contents of the RDRF, PER, FER, and ORER flags, or the contents of RDR. When the external
clock is used in asynchronous mode, the clock must be supplied even during initialization.
Set CKE1 and CKE0 bits in SCR
SCR to 1, and set RIE, TIE, TEIE,
Clear TE and RE bits in SCR to 0
SCI Initialization (Asynchronous Mode)
Set data transfer format in
<Initialization completed>
1-bit interval elapsed?
Set TE and RE bits in
Start of initialization
SMR and SCMR
Set value in BRR
(TE, RE bits 0)
and MPIE bits
Figure 15.5 Sample SCI Initialization Flowchart
Yes
Wait
No
[1]
[2]
[3]
[4]
Section 15 Serial Communication Interface (SCI, IrDA)
[1] Set the clock selection in SCR.
[2] Set the data transfer format in SMR
[3] Write a value corresponding to the
[4] Wait at least one bit interval, then
Be sure to clear bits RIE, TIE,
TEIE, and MPIE, and bits TE and
RE, to 0.
When the clock is selected in
asynchronous mode, it is output
immediately after SCR settings are
made.
and SCMR.
bit rate to BRR. (Not necessary if
an external clock is used.)
set the TE bit or RE bit in SCR to 1.
Also set the RIE, TIE, TEIE, and
MPIE bits.
Setting the TE and RE bits enables
the TxD and RxD pins to be used.
Rev. 1.00 Sep. 19, 2008 Page 873 of 1270
REJ09B0466-0100