Hitachi H8S/2646 Hardware Manual page 549

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.
ø
N =
S × 2 × B
2n+1
Table 14-6 Examples of BRR Settings for Bit Rate B (bit/s) (When n = 0 and S = 372)
7.1424
bit/s N Error N
9600 0 0.00 1
Table 14-7 Maximum Bit Rate at Various Frequencies (Smart Card Interface Mode)
(when S = 372)
ø (MHz)
7.1424
10.00
10.7136
13.00
14.2848
16.00
18.00
20.00
The bit rate error is given by the following formula:
Error (%) = (
S × 2
× 10
6
– 1
10.00 10.7136
Error N Error N
30 1 25 1
Maximum Bit Rate (bit/s)
9600
13441
14400
17473
19200
21505
24194
26882
ø
× B × (N + 1)
2n+1
ø (MHz)
13.00 14.2848
Error N Error N
8.99 1 0.00 1
N
0
0
0
0
0
0
0
0
× 10 – 1) × 100
6
16.00 18.00
Error N Error N
12.01 2 15.99 2
n
0
0
0
0
0
0
0
0
20.00
Error
6.60
517