H8SSLASH2218 datasheet(479/750 Pages) RENESAS

479 / 750 page

Section 12 Serial Communication Interface

Rev.6.00 Jun. 03, 2008 Page 431 of 698

REJ09B0074-0600

12.7.6

Initialization

Before transmitting and receiving data, initialize the SCI as described below. Initialization is also

necessary when switching from transmit mode to receive mode, or vice versa.

1. Clear the TE and RE bits in SCR to 0.

2. Clear the error flags ERS, PER, and ORER in SSR to 0.

3. Set the GM, BLK, O/

E, BCP0, BCP1, CKS0, CKS1 bits in SMR. Set the PE bit to 1.

4. Set the SMIF, SDIR, and SINV bits in SCMR.

When the SMIF bit is set to 1, the TxD and RxD pins are both switched from ports to SCI pins,

and are placed in the high-impedance state.

5. Set the value corresponding to the bit rate in BRR.

6. Set the CKE0 and CKE1 bits in SCR. Clear the TIE, RIE, TE, RE, MPIE, and TEIE bits to 0.

If the CKE0 bit is set to 1, the clock is output from the SCK pin.

7. Wait at least one bit interval, then set the TIE, RIE, TE, and RE bits in SCR. Do not set the TE

bit and RE bit at the same time, except for self-diagnosis.

To switch from receive mode to transmit mode, after checking that the SCI has finished reception,

initialize the SCI, and set RE to 0 and TE to 1. Whether SCI has finished reception or not can be

checked with the RDRF, PER, or ORER flags. To switch from transmit mode to receive mode,

after checking that the SCI has finished transmission, initialize the SCI, and set TE to 0 and RE to

1. Whether SCI has finished transmission or not can be checked with the TEND flag.

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