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MC80F0424 Datasheet, PDF (90/135 Pages) List of Unclassifed Manufacturers – 8-BIT SINGLE-CHIP MICROCONTROLLERS
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MC80F0424/0432/0448
Preliminary
still transferred to RXR. When bit 1 (ISRM) of
ASIMR(ASIMR1) is cleared to 0 upon occurrence of an error, in-
terrupt by Rx occurs. When ISRM bit is set to 1, interrupt by Rx
does not occur in case of error occurrence. Figure 17-3 shows the
timing of the asynchronous serial interface receive completion in-
terrupt request.
17.4 Relationship between main clock and baud rate
The transmit/receive clock that is used to generate the baud rate
is obtained by dividing the main system clock or ACLK0/ACLK1
pin clock. The baud rate generated from the main system clock or
ACLK0/ACLK1 pin clock is determined according to the follow-
ing formula. If the high 4 bits of BRGCR/BRGCR1 is 0, ACLK0/
ACLK1 pin clock is used for source clock of baud rate generator.
Baud Rate = fXIN / ( 2n+1(k+16) )
- fXIN : Main system clock oscillation frequency
When ACLK0/ACLK1 is selected as the source clock of
the 5-bit counter, substitute the input clock frequency to
ACLK0/ACLK1 pin clock for in the above expression.
- n : Value set via TPS0 to TPS2 (0 ≤ n ≤ 7)
- k : Value set via MDL0 to MDL3 (0 ≤ k ≤ 14)
Baud Rate
(bps)
fXIN=12M
BRGCR
ERR
(%)
600
-
-
1200
-
-
2400
74H
2.34
4800
64H
2.34
9600
54H
2.34
19200
44H
2.34
31250
38H
0.00
38400
34H
2.34
57600
2AH 0.16
76800
24H
2.34
115200
1AH 0.16
fXIN=11.0592M
BRGCR
ERR
(%)
-
-
-
-
72H 0.00
62H 0.00
52H 0.00
42H 0.00
36H
0.53
32H 0.00
28H
0.00
22H
0.00
18H
0.00
fXIN=10.0M
BRGCR
ERR
(%)
-
-
-
-
70H 1.73
60H 1.73
50H 1.73
40H 1.73
34H 0.00
30H 1.73
26H 1.35
20H 1.73
16H 1.36
fXIN=8.0M
BRGCR
ERR
(%)
-
-
7AH
0.16
6AH
0.16
5AH
0.16
4AH
0.16
3AH
0.16
30H
0.00
2AH
0.16
21H
2.11
1AH
0.16
11H
2.12
fXIN=6.0M
BRGCR
ERR
(%)
-
-
74H
2.34
64H
2.34
54H
2.34
44H
2.34
34H
2.34
28H
0.00
24H
2.34
1AH
0.16
14H
2.34
-
-
fXIN=5.0M
BRGCR
ERR
(%)
-
-
70H 1.73
60H 1.73
50H 1.73
40H 1.73
30H 1.73
24H 0.00
20H 1.73
16H 1.36
10H 1.73
-
-
fXIN=4.0M
BRGCR
ERR
(%)
7AH 0.16
6AH 0.16
5AH 0.16
4AH 0.16
3AH 0.16
2AH 0.16
20H 0.00
1AH 0.16
11H 2.12
-
-
-
-
Table 17-5 Relationship between main clock and Baud Rate
86
MAR. 2005 Ver 0.2
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