AR-B9673 User’s Guide
12
3.10 FLOPPY DRIVE CONNECTOR (FDD1)
The AR-B9673 provides a 34-pin header type connector for supporting up to two floppy disk drives.
To enable or disable the floppy disk controller, please use the BIOS Setup program.
33
34
1
2
3.11 SRAM. MEMORY BANK ADDRESS SELECT (XP3)
This section provides the information about how to use the SRAM. It divided into two parts: hardware setting and
software configuration.
Step 1: Use XP3 to select the correct SRAM memory address.
Step 2: Insert programmed SRAM into IC U18 setting as SRAM.
The hardware divides every 16KB of memory into a memory bank. User to assign a bank number,
Memory bank start from 00, last memory bank number depends on the size to the SRAM chip.
If on board the 512KB SRAM chip, the memory bank in the range of 00 to 31. The SRAM I/O Port =
78H
.
Example: Select the 10th bank of the U18. Using 512K*8, the I/O port =78H
Answer 1:
(in assembly language)
MOV DX, 78H ; AR-B9673’s I/O port=78h
MOV AL, 10 ; Selection the 10th bank
OUT DX, AL ;
Answer 2
: (in Basic language)
OUT &H78,&10 : AR-B9673’s I/O port=78h
Answer 3
:(in Turbo C language)
Outportb(0x78,10)
PIN
Signal
PIN
Signal
1-33(odd) GROUND
18
DIRECTION
2
DRVEN 0
20
-STEP OUTPUT PULSE
4
NOT USED
22
-WRITE DATA
6
DRVEN 1
24
-WRITE GATE
8 -INDEX
26 -TRACK
0
10
-MOTOR ENABLE 0
28
-WRITE PROTECT
12
-DRIVE SELECT 1
30
-READ DATA
14
-DRIVE SELECT 0
32
-SIDE 1 SELECT
16
-MOTOR ENABLE 1
34
DISK CHANGE
XP3
ADDRESS
1-2
CE00
(Factory Preset)
2-3 D800
