2 cpu base clock select (jp1), 3 switch settings (sw1), 4 external led header (j1) – Acrosser AR-B1320 User Manual
Page 24
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B
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1
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2
2
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0
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U
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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-