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Start of initialization
Clear TE and RE bits
to 0 in SCR
Set CKE1 and CKE0 bits
1
in SCR (leaving TE and
RE bits cleared to 0)
2
Select communication
format in SMR
3
Set value in BRR
Wait
No
1 bit interval
elapsed?
Yes
Set TE or RE bit to 1 in SCR
Set RIE, TIE, TEIE, and
4
MPIE bits as necessary
Transmitting or receiving
Figure 11-4 Sample Flowchart for SCI Initialization
1.
Select the clock source in SCR. Clear the RIE, TIE, TEIE,
MPIE, TE, and RE bits to 0. If clock output is selected in
asynchronous mode, clock output starts immediately after
the setting is made in SCR.
2.
Select the communication format in SMR.
3.
Write the value corresponding to the bit rate in BRR.
This step is not necessary when an external clock is used.
4.
Wait for at least the interval required to transmit or receive
1 bit, then set the TE or RE bit to 1 in SCR. Set the RIE,
TIE, TEIE, and MPIE bits as necessary. Setting the TE
or RE bit enables the SCI to use the TxD or RxD pin.
343
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