Initialization - Renesas H8S Family Hardware Manual

Receive data

Synchronization

sampling timing

Data sampling

Figure 13.25 Receive Data Sampling Timing in Smart Card Interface Mode

Initialization

Before starting transmitting and receiving data, initialize the SCI using the following procedure.

Initialization is also necessary before switching from transmission to reception and vice versa.

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

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

3. Set the GM, BLK, O/E, BCP1, BCP0, CKS1, and CKS0 bits in SMR appropriately. Also set

the PE bit to 1.

4. Set the SMIF, SDIR, and SINV bits in SCMR appropriately. When the SMIF bit is set to 1, the

TxD and RxD pins are changed from port pins to SCI pins, placing the pins into high

impedance state.

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

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

TEIE bits to 0 simultaneously. When the CKE0 bit is set to 1, the SCK pin is allowed to output

clock pulses.

7. Set the TIE, RIE, TE, and RE bits in SCR appropriately after waiting for at least 1 bit interval.

Setting prohibited the TE and RE bits to 1 simultaneously except for self diagnosis.

372 clock cycles

(When Clock Frequency is 372 Times the Bit Rate)

Section 13 Serial Communication Interface (SCI)

Rev. 1.00 Mar. 12, 2008 Page 479 of 1178

REJ09B0403-0100