Floppy Dis K Controller Boards; Model 431 Floppy Disk Controller Board - IMS 5000 Series Manual

2.8 FLOPPY DIS K CONTROLLER BOARDS
2.8.1 MODEL 431 FLOPPY DISK CONTROLLER BOARD
The Industrial Micro Systems Model 431 floppy disk controller
1S
used with
5-1/4" floppy drives.
The 431 is based on the NEC uPD765 floppy disk controller chip, providing
single and double density and single and double sided operation. An 8257
provides DMA operation. The 431 board can control up to four floppy drives.
CONFIGURING THE 431 BOARp
I/O Address Selection (Location TM
The values of the mos t significant bits of the 431's I/O addresses are indicated
by the shunts at location JA. A shunt on the right (as in A7 below) gives a
"1"
value to the address bit; a shunt to the left (as in A5 below) gives a "0" value to
that bit. The addresses selected by the shunts below are COH to CFH, which is
the normal setting.
JA
A7
0 0 _ _ 0
A6
0 0 _ _ 0
A5
0 _ _ 0 0
A4
0 _ _ 0 0
(etched)
(shunted)
(etched)
(etched)
vectored Interrupt Level Selection (Location TB)
The J B area is used to select one of the eight vectored interrupt levels to be
triggered when a floppy disk controller interrupt or a delay complete interrupt
occur, depending upon the status of the interrupt mask port (OUT CCH). The
pins 0-7 correspond to interrupt levels VIO-VI7, respectively.
pouble Sided Drive Selection (Location IC)
The JC shunt location is used to indicate single sided (no shunt) or double sided
(shunt installed) operation.
I/O ADPRESSES FOR THE 431 BOARP
COH-C8H - 8257 DMA Controller
COH -
C1H
C2H
C3H
C4H
C5H
C6H
C7H
Channel 0
Channel 0
Channel 1
Channel 1
Channel 2
Channel 2
Channel 3
Channel 3
DMA Register
Terminal Count Register
DMA Register
Terminal Count Register
DMA Register
Terminal Count Register
DMA Regis ter
Terminal Count Register
will be reserved for
hard disk controller
will be reserved for
2nd hard disk
controller
C8H -
DMA Status and Commands
IMS International
5000 Series Microcornputers/7.01.83;Page 71