Datasheet

Section 16 Serial Communication Interface (SCI, IrDA)
(The H8S/2695 is not equipped with an IrDA function)
Page 762 of 1434 R01UH0166EJ0600 Rev. 6.00
Mar 02, 2011
H8S/2633 Group, H8S/2633 F-ZTAT
TM
,
H8S/2633R F-ZTAT
TM
, H8S/2695
Data Transfer Operations
SCI initialization (asynchronous 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 below.
When the operating mode, transfer format, etc., is changed, the TE and RE bits must be cleared to
0 before making the change using the following procedure. When the TE bit is cleared to 0, the
TDRE flag is set to 1 and TSR is initialized. 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.
When an external clock is used the clock should not be stopped during operation, including
initialization, since operation is uncertain.
Figure 16.4 shows a sample SCI initialization flowchart.
Wait
<Transfer completion>
Start initialization
Set data transfer format in
SMR and SCMR
[1]
Set CKE1 and CKE0 bits in SCR
(TE, RE bits 0)
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
[4]
1-bit interval elapsed?
[1] Set the clock selection in SCR.
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.
[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 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.
Figure 16.4 Sample SCI Initialization Flowchart