Fdd Interface Circuit - Panasonic JS-170FR Series Service Manual

2.1.5.4

FDD interface circuit

The IT8673F is used as a floppy disc controller.
The FDC functions of the IT8673F are compatible with Devices 765A, DP8473. The interface circuit is made AT-compatible.
All the output signals to the FDD are processed in the open collector mode, pulled up with 1kΩ.
All the input signals from the FDD are pulled up with 2.2kΩ.
Protection for the WGATE signal is assured by the hardware, using its own signal of FDDEN.
I T 8 7 6 3 F
16
I N D E X
8
D R V 0
7
D R V 1
20
D S K C H G
6
M T 0
9
M T 1
11
F D I R
12
S T E P
13
W D ATA
14
W G AT E
17
T R K 0
18
W P R T
19
R D ATA
15
H D S E L
5
D E N S E L
+5V
1K 1K 1K
GATEARAY
158
W G AT E - O U T #
2
W G AT E - I N #
2-21
2.2K
2.2K
+5V
1
GND
2
I N D E X #
3
+5V
4
D R V 0 #
5
G N D
6
D C H G #
7
8
9
1 0
+ 5 V
11
M T R 0 #
1 2
D I R
1 3
D E N S L
1 4
S T E P #
1 5
G N D
1 6
W D ATA #
1 7
G N D
1 8
W G AT E #
1 9
G N D
2 0
T R K 0 #
2 1
G N D
2 2
W P R T #
2 3
R D ATA #
2 4
G N D
2 5
S I D E S E L 0
2 6
5 2 6 2 9 - 2 6 1 1