pc87317vul National Semiconductor Corporation, pc87317vul Datasheet - Page 178

• Manufacturer Part Number: pc87317vul
• Description: Pc87317vul/pc97317vul Superi/o Plug And Play Compatible With Acpi Compliant Controller/extender
• Manufacturer: National Semiconductor Corporation

www.national.com
7.13.1 Baud Generator Divisor Ports, LSB (BGD(L))
These ports perform the same function as the Legacy Baud
Divisor Ports in Bank 1 and are accessed identically, but do
not change the operation mode of the module when access-
ed. Refer to Section 7.12.1 on page 177 for more details.
Use these ports to set the baud when operating in Extended
mode to avoid fallback to a Non-Extended operation mode,
i.e., 16550 compatible.When programming the baud, writ-
ing to BGDH causes the baud to change immediately.
x
7
x
6
and MSB (BGD(H))
FIGURE 7-21. BGD(L) Register Bitmap
x
5
x
4
Prescaler Value
x
3
1500000
115200
230400
460800
750000
921600
14400
19200
28800
38400
57600
Baud
134.5
Least Significant Byte
1200
1800
2000
2400
3600
4800
7200
9600
x
110
150
300
600
2
50
75
x
1
of Baud Generator
x
0
Reset
Required
Enhanced Serial Port with IR - UART2 (Logical Device 5)
Baud Generator Divisor
Divisor
2304
1536
1047
857
768
384
192
96
64
58
48
32
24
16
12
---
---
---
---
---
8
6
4
3
2
1
Low Byte Port
TABLE 7-14. Baud Generator Divisor Settings
13
Offset 00h
% Error
0.16%
0.16%
0.19%
0.10%
0.16%
0.16%
0.16%
0.16%
0.16%
0.53%
0.16%
0.16%
0.16%
0.16%
0.16%
0.16%
0.16%
0.16%
0.16%
0.16%
0.16%
(BGD(L))
Bank 2,
---
---
---
---
---
178
Divisor
18461
12307
8391
6863
6153
3076
1538
769
512
461
384
256
192
128
96
64
48
32
24
16
---
---
8
4
2
1
x
7
1.625
x
6
FIGURE 7-22. BGD(H) Register Bitmap
% Error
x
5
0.00%
0.01%
0.01%
0.00%
0.01%
0.03%
0.03%
0.03%
0.16%
0.12%
0.16%
0.16%
0.16%
0.16%
0.16%
0.16%
0.16%
0.16%
0.16%
0.16%
0.16%
0.16%
0.16%
0.16%
---
---
x
4
x
3
Most Significant Byte
x
2
Divisor
30000
20000
13636
11150
10000
5000
2500
1250
833
750
625
416
312
208
156
104
x
78
52
39
26
13
1
---
---
---
2
1
of Baud Generator
x
0
Reset
Required
1
Baud Generator Divisor
% Error
0.00%
0.00%
0.00%
0.02%
0.00%
0.00%
0.00%
0.00%
0.04%
0.00%
0.00%
0.16%
0.16%
0.16%
0.16%
0.16%
0.16%
0.16%
0.16%
0.16%
0.16%
0.00%
0.00%
---
---
---
High Byte Port
Offset 01h
(BGD(H))
Bank 2,