Sharp PC-6220 Service Manual page 96

12-4. Block diagram
1~in
Address
r=
decode
110
port
I
~
2.
'---'
HOST
19.2MHz Select
' - - - J
k:-
Floppy
disk
. controller
EXT.key
<-
interface
Rg.12-2 3.5 inch Portable FDD
12-5. Circuit description
It incorporates the 3.5" floppy disK driVe and its interface to make
expansion of the PC-6220. In tlie CE-621 F is contained the IBM PS/2
full keyboard, 5.25': floppy disk drive interface, and external keyboard
interrace. ' . ' _
Assignment of the 3.5" and 5.25" FDD can be selected via the Sharp
original port (SOP).
To
-make it connected, write the pOinter address
01 H) in 7CH, then write data in SOP 7DH. 7CH
will
be cleared to
DOH.
(1)
1/0
address
Address
ReadlWrite
Function
lID allocation
7CH
Write Pointer address setting
01H
7DH
Write
Key allocation setting
BitS
7DH
Write
FDD allocation setting
Bit2,1,0
bitS
Key selection
0 Internal key
1
External key
bit2
bit1
bitO Internal drive
External drive
0
0
0 DriveO
Drive1
0
0
1
Drive1
DriveO
-94-
' ; ;
;
D-SUB
'"
, 25,E!n
,
:::EXT,
r;::::::
--------_.
5inch
.
ROD
,
"-
'-:-
-
,
Drive
==;;
)sel~,ct
,
,
,
;
'-~"-
.-,
-,."
,
-
--
Internal
3.5inch
FDD
M-DIN
6~
L-
m.hml
~:.
I