User`s guide

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3-4
3.2 CPU BASE CLOCK SELECT (JP1)
This board provides six types of CPU input clocks; they are 33.3MHz, 50MHz, 60MHz, 66.7MHz,
75MHz, and 80MHz. The CPU input clock is twice that of the operating clock. JP1 is a 6-pin
jumper located between CN3 and CN4.
CPU Input Clock CPU Operating Clock JP1 Setting Remark
33.3MHz 16.7MHz Short 1-2 & 4-6
50MHz 25MHz Short 1-2 & 3-5
60MHz 30MHz Short 1-2 & 5-6
66.7MHz 33.3MHz Short 1-3 & 5-6 Factory Preset
75MHz 37.5MHz Short 2-4 & 5-6
80MHz 40MHz Short 1-3 & 2-4
Table 3-2 CPU Clock Settings
Figure 3-2 JP1: CPU Clock Select
3.3 SWITCH SETTINGS (SW1)
SW1 is a 6-SPST DIP switch. It provides multi-purpose selection in one switch. The following
table gives the details:
SW1 Function When “OFF” When “ON” Factory Preset
Switch 1 Selects the base I/O address of SSD 210H-211H 290H-291H Off
Switch 2 Selects the memory segment of SSD C800H(8KB) D800H(8KB) Off
Switch 2 Selects the memory segment of DiskOnChip
(If Switch 3 is set as “ON”)
CA00H(8KB) DA00H(8KB) Off
Switch 3 DiskOnChip select Disabled Enabled Off
Switch 4 Reserved --- --- Off
Switch 5 COM-A port mode select RS-232C RS-485 Off
Switch 6 COM-B port mode select RS-232C RS-485 Off
Table 3-3 SW1 Settings
3.4 EXTERNAL LED HEADER (J1)
The J1 is a 4-pin right angle header. It allows you to connect an external power LED and an
external hard disk LED.
Figure 3-3 J1: External LED Header
1
3
5 6
4
2
JP1
16.7MHz
1
3
5 6
4
2
JP1
25MHz
1
3
5 6
4
2
JP1
30MHz
1
3
5 6
4
2
JP1
33.3MHz
1
3
5 6
4
2
JP1
37.5MHz
1
3
5 6
4
2
JP1
40MHz
2
1 3
4
J1
Front View
1: Power LED+
3: Power LED-
2: Hard Disk LED+
4: Hard Disk LED-