Datasheet

Section 17 Serial Communications Interface 3 (SCI3, IrDA)
Rev. 2.00 Jul. 04, 2007 Page 383 of 692
REJ09B0309-0200
17.4.2 SCI3 Initialization
Follow the flowchart as shown in figure 17.4 to initialize the SCI3. 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 OER flags, or the contents of RDR. When the external clock is used in
asynchronous mode, the clock must be supplied even during initialization. When the external
clock is used in clock synchronous mode, the clock must not be supplied during initialization.
Wait
Start initialization
Set data transfer format in SMR
[1]
Set CKE1 and CKE0 bits in SCR3
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.
Set SPC3 bit in SPCR or SPCR2 to 1
[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 output is selected in
asynchronous mode, clock is output
immediately after CKE1 and CKE0
settings are made. When the clock
output is selected at reception in clocked
synchronous mode, clock is output
immediately after CKE1, CKE0, and RE
are set to 1.
[2] Set the data transfer format in SMR.
[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. Setting bits
TE and RE enables the TXD3 and RXD3
pins to be used. Also set the RIE, TIE,
TEIE, and MPIE bits, depending on
whether interrupts are required. In
asynchronous mode, the bits are marked
at transmission and idled at reception to
wait for the start bit.
End
Figure 17.4 Sample SCI3 Initialization Flowchart