Datasheet

Section 15 Smart Card Interface
Rev.6.00 Sep. 27, 2007 Page 685 of 1268
REJ09B0220-0600
The method of calculating the value to be set in the bit rate register (BRR) from the operating
frequency and bit rate, on the other hand, is shown below. N is an integer, 0 ≤ N ≤ 255, and the
smaller error is specified.
N =
φ
S × 2
2n+1
× B
× 10
6
– 1
Table 15.6 Examples of BRR Settings for Bit Rate B (bits/s) (When n = 0 and S = 372)
φ (MHz)
7.1424 10.00 10.7136 13.00 14.2848 16.00 18.00 20.00 25.00
Bits/s N Error N Error N Error N Error N Error N Error N Error N Error N Error
9600 0 0.00 1 30 1 25 1 8.99 1 0.00 1 12.01 2 15.99 2 6.60 3 12.49
Table 15.7 Maximum Bit Rate at Various Frequencies (Smart Card Interface Mode)
(When S = 372)
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
25.00 33602 0 0
The bit rate error is given by the following formula:
Error (%) = (
φ
S × 2
2n+1
× B × (N + 1)
× 10
6
– 1) × 100