Datasheet

Section 15 Serial Communication Interface (SCI, IrDA)
R01UH0309EJ0500 Rev. 5.00 Page 913 of 1408
Sep 24, 2012
H8S/2456, H8S/2456R, H8S/2454 Group
15.6.2 SCI Initialization (Clocked Synchronous Mode)
Before transmitting and receiving data, you should first clear the TE and RE bits in SCR to 0, then
initialize the SCI as described in a sample flowchart in figure 15.15. 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 change the contents of the RDRF, PER, FER, and ORER flags, or the contents of RDR.
Wait
<Transfer start>
Start of initialization
Set data transfer format in
SMR and SCMR
No
Yes
Set value in BRR
Clear TE and RE bits in SCR to 0
[2]
[3]
Set TE and RE bits in SCR to 1, and
set RIE, TIE, TEIE, and MPIE bits
Note: In simultaneous transmit and receive operations, the TE and RE bits should
both be cleared to 0 or set to 1 simultaneously.
[4]
1-bit interval elapsed?
Set CKE1 and CKE0 bits in SCR
(TE, RE bits 0)
[1]
[1] Set the clock selection in SCR. Be sure
to clear bits RIE, TIE, TEIE, and MPIE,
TE and RE, to 0.
[2] Set the data transfer format in SMR
and SCMR.
[3] Write a value corresponding to the bit
rate to BRR. (Not necessary if an
external clock is used.)
[4] Wait at least one bit interval, then set
the TE and RE bits in SCR to 1.
Also set the RIE, TIE, TEIE, and MPIE
bits.
Setting the TE and RE bits enable the
TxD and RxD pins to be used.
Figure 15.15 Sample SCI Initialization Flowchart