Hitachi H8/3048 Hardware Manual page 470

Table 13-4 Examples of Bit Rates and BRR Settings in Synchronous Mode
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2
Bit Rate
n N
(bits/s)
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 transmit/receive 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)
N: BRR setting for baud rate generator (0 ≤ N ≤ 255)
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 8
n N n N
— — — —
2 249 3 124
2 124 2 249
1 249 2 124
1 99 1 199
0 199 1 99
0 99 0 199
0 39 0 79
0 19 0 39
0 9 0 19
0 3 0 7
0 1 0 3
0 0* 0 1
0 0*
— —
× 10
6
– 1
× 10
6
– 1
ø (MHz)
10 13
n N n N
— — — —
— — 3 202
— — 3 101
— — 2 202
1 249 2 80
1 124 1 162
0 249 1 80
0 99 0 129
0 49 0 64
0 24 — —
0 9 0 12
0 4 — —
— — — —
— — — —
0 0* — —
459
16 18
n N n N
— — — —
3 249 — —
3 124 3 140
2 249 3 69
2 99 2 112
1 199 1 224
1 99 1 112
0 159 0 179
0 79 0 89
0 39 0 44
0 15 0 17
0 7 0 8
0 3 0 4
0 1 — —
— — — —
0 0* — —