Hitachi H8/3022 Hardware Manual page 356

Table 11-4 Examples of Bit Rates and BRR Settings in Synchronous Mode
Bit Rate 2
(bits/s) n N
110 3 70
250 2 124
500 1 249
1 k 1 124
2.5 k 0 199
5 k 0 99
10 k 0 49
25 k 0 19
50 k 0 9
100 k 0 4
250 k 0 1
500 k 0 0*
1 M
2 M
2.5 M
4 M
Note: Settings with an error of 1% or less are recommended.
Legend
Blank: No setting available
—: Setting possible, but error occurs
*: Continuous transmission/reception not possible
The BRR setting is calculated as follows:
Asynchronous mode:
ø
N =
64 × 2 × B
2n-1
Synchronous mode:
ø
N =
8 × 2 × B
2n-1
B: Bit rate (bits/s)
BRR setting for baud rate generator (0 ≤ N ≤ 255)
N:
ø: System clock frequency (MHz)
n: Baud rate generator clock source (n = 0, 1, 2, 3)
(For the clock sources and values of n, see the following table.)
4
n N n
— — —
2 249 3
2 124 2
1 249 2
1 99 1
0 199 1
0 99 0
0 39 0
0 19 0
0 9 0
0 3 0
0 1 0
0 0* 0
0
—
× 10
6
– 1
× 10
6
– 1
ø (MHz)
8 10
N n N
— — —
124 — —
249 — —
124 — —
199 1 249
99 1 124
199 0 249
79 0 99
39 0 49
19 0 24
7 0 9
3 0 4
1 — —
0* — —
— 0 0*
16
n N n
— — —
3 249 —
3 124 3
2 249 3
2 99 2
1 199 1
1 99 1
0 159 0
0 79 0
0 39 0
0 15 0
0 7 0
0 3 0
0 1 —
— — —
0 0* —
18
N
—
—
140
69
112
224
112
179
89
44
17
8
4
—
—
—
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