HD6413007F20 Datasheet, PDF (531/798 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series

14. Smart Card Interface
Table 14.7 Maximum Bit Rates for Various Frequencies (Smart Card Interface Mode)
φ (MHz)
Maximum Bit Rate (bits/s)
N
n
7.1424
9600
0
0
10.00
13441
0
0
10.7136
14400
0
0
13.00
17473
0
0
14.2848
19200
0
0
16.00
21505
0
0
18.00
24194
0
0
20.00
26882
0
0
The bit rate error is given by the following equation:
Error (%) =
φ
× 10⁶ – 1 × 100
1488 × 2^2n-1 × B × (N + 1)
14.3.6 Transmitting and Receiving Data
Initialization: Before transmitting or receiving data, the smart card interface must be initialized 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 to 0 in the serial control register (SCR).
2. Clear error flags ERS, PER, and ORER to 0 in the serial status register (SSR).
3. Set the parity bit (O/E) and baud rate generator select bits (CKS1 and CKS0) in the serial
mode register (SMR). Clear the C/A, CHR, and MP bits to 0, and set the STOP and PE bits to
1.
4. Set the SMIF, SDIR, and SINV bits in the smart card mode register (SCMR).
When the SMIF bit is set to 1, the TxD pin and RxD pin are both switched from port to SCI pin
functions and go to the high-impedance state.
5. Set a value corresponding to the desired bit rate in the bit rate register (BRR).
6. Set the CKE0 bit in SCR. Clear the TIE, RIE, TE, RE, MPIE, TEIE, and CKE1 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.
Rev.5.00 Sep. 12, 2007 Page 501 of 764
REJ09B0396-0500