H8S2633 Datasheet, PDF (874/1487 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8S Family/H8S/2600 Series

Section 17 Smart Card Interface
17.4 Usage Notes
The following points should be noted when using the SCI as a Smart Card interface.
Receive Data Sampling Timing and Reception Margin in Smart Card Interface Mode: In
Smart Card interface mode, the SCI operates on a basic clock with a frequency of 32, 64, 372, or
256 times the transfer rate (as determined by bits BCP1 and BCP0).
In reception, the SCI samples the falling edge of the start bit using the basic clock, and performs
internal synchronization. Receive data is latched internally at the rising edge of the 16th, 32nd,
186th, or 128th pulse of the basic clock. Figure 17.10 shows the receive data sampling timing
when using a clock of 372 times the transfer rate.
372 clocks
186 clocks
0
185
371 0
Internal
basic
clock
Receive
data (RxD)
Start bit
D0
185
371 0
D1
Synchro-
nization
sampling
timing
Data
sampling
timing
Figure 17.10 Receive Data Sampling Timing in Smart Card Mode
(Using Clock of 372 Times the Transfer Rate)
Rev. 5.00 Mar 28, 2005 page 812 of 1422
REJ09B0234-0500