127
AT94KAL Series FPSLIC
Rev. 1138G–FPSLI–11/03
Table 36.
UBR Settings at Various Crystal Frequencies
UART0 and UART1 High Byte Baud-rate Register UBRRHI
The UART baud register is a 12-bit register. The 4 most significant bits are located in a sepa-
rate register, UBRRHI. Note that both UART0 and UART1 share this register. Bit 7 to bit 4 of
UBRRHI contain the 4 most significant bits of the UART1 baud register. Bit 3 to bit 0 contain
the 4 most significant bits of the UART0 baud register.
Clock
MHz
UBRRHI
7:4 or 3:0 UBRRn
UBR
HEX
UBR
Actual
Freq
Desired
Freq.
%
Error
Clock
MHz
UBRRHI
7:4 or 3:0
UBRRn
UBR
HEX
UBR
Actual
Freq
Desired
Freq.
%
Error
1
0000
00011001
019
25
2404
2400
0.2
1.8432
0000
00101111
02F
47
2400
2400
0.0
0000
00001100
00C
12
4808
4800
0.2
0000
00010111
017
23
4800
4800
0.0
0000
00000110
006
6
8929
9600
7.5
0000
00001011
00B
11
9600
9600
0.0
0000
00000011
003
3
15625
14400
7.8
0000
00000111
007
7
14400
14400
0.0
0000
00000010
002
2
20833
19200
7.8
0000
00000101
005
5
19200
19200
0.0
0000
00000001
001
1
31250
28880
7.6
0000
00000011
003
3
28800
28880
0.3
0000
00000001
001
1
31250
38400
22.9
0000
00000010
002
2
38400
38400
0.0
0000
00000000
000
0
62500
57600
7.8
0000
00000001
001
1
57600
57600
0.0
0000
00000000
000
0
62500
76800
22.9
0000
00000001
001
1
57600
76800
33.3
0000
00000000
000
0
62500
115200
84.3
0000
00000000
000
0
115200
115200
0.0
Clock
MHz
UBRRHI
7:4 or 3:0 UBRRn
UBR
HEX
UBR
Actual
Freq
Desired
Freq.
%
Error
Clock
MHz
UBRRHI
7:4 or 3:0
UBRRn
UBR
HEX
UBR
Actual
Freq
Desired
Freq.
%
Error
9.216
0000
11101111
0EF
239
2400
2400
0.0
18.432
0001
11011111
1DF
479
2400
2400
0.0
0000
01110111
077
119
4800
4800
0.0
0000
11101111
0EF
239
4800
4800
0.0
0000
00111011
03B
59
9600
9600
0.0
0000
01110111
077
119
9600
9600
0.0
0000
00100111
027
39
14400
14400
0.0
0000
01001111
04F
79
14400
14400
0.0
0000
00011101
01D
29
19200
19200
0.0
0000
00111011
03B
59
19200
19200
0.0
0000
00010011
013
19
28800
28880
0.3
0000
00100111
027
39
28800
28880
0.3
0000
00001110
00E
14
38400
38400
0.0
0000
00011101
01D
29
38400
38400
0.0
0000
00001001
009
9
57600
57600
0.0
0000
00010011
013
19
57600
57600
0.0
0000
00000111
007
7
72000
76800
6.7
0000
00001110
00E
14
76800
76800
0.0
0000
00000100
004
4
115200
115200
0.0
0000
00001001
009
9
115200
115200
0.0
0000
00000001
001
1
288000
230400
20.0
0000
00000100
004
4
230400
230400
0.0
0000
00000000
000
0
576000
460800
20.0
0000
00000001
001
1
576000
460800
20.0
0000
00000000
000
0
576000
912600
58.4
0000
00000000
000
0
1152000
912600
20.8
Clock
MHz
UBRRHI
7:4 or 3:0 UBRRn
UBR
HEX
UBR
Actual
Freq
Desired
Freq.
%
Error
Clock
MHz
UBRRHI
7:4 or 3:0
UBRRn
UBR
HEX
UBR
Actual
Freq
Desired
Freq.
%
Error
25.576
0010
10011001
299
665
2400
2400
0.0
40
0100
00010001
411
1041
2399
2400
0.0
0001
01001100
14C
332
4800
4800
0.0
0010
00001000
208
520
4798
4800
0.0
0000
10100110
0A6
166
9572
9600
0.3
0001
00000011
103
259
9615
9600
0.2
0000
01101110
06E
110
14401
14400
0.0
0000
10101100
0AC
172
14451
14400
0.4
0000
01010010
052
82
19259
19200
0.3
0000
10000001
081
129
19231
19200
0.2
0000
00110110
036
54
29064
28880
0.6
0000
01010110
056
86
28736
28880
0.5
0000
00101001
029
41
38060
38400
0.9
0000
01000000
040
64
38462
38400
0.2
0000
00011011
01B
27
57089
57600
0.9
0000
00101010
02A
42
58140
57600
0.9
0000
00010100
014
20
76119
76800
0.9
0000
00100000
020
32
75758
76800
1.4
0000
00001101
00D
13
114179
115200
0.9
0000
00010101
015
21
113636
115200
1.4
0000
00000110
006
6
228357
230400
0.9
0000
00001010
00A
10
227273
230400
1.4
0000
00000011
003
3
399625
460800
15.3
0000
00000100
004
4
500000
460800
7.8
0000
00000001
001
1
799250
912600
14.2
0000
00000010
002
2
833333
912600
9.5
Bit
7
6
5
4
3
2
1
0
$20 ($40)
MSB1
LSB1
MSB0
LSB0
UBRRHI
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Initial Value
0
0
0
0
0
0
0
0