Floppy Disk Controller
(l)UMC
UM8272A / UM8272A'-4
: : : : : : : : : : : : : Floppy Disk Controller
Features
• IBM Compatible in Both Singl...
Description
(l)UMC
UM8272A / UM8272A'-4
: : : : : : : : : : : : : Floppy Disk Controller
Features
IBM Compatible in Both Single and Double Density Recording Formats
Programmable Data Record Lengths: 128, 256, 512, or 1024 Bytes/Sector
Multi-Sector and Multi-Track Transfer Capability Drives Up to 4 Floppy or Mini-Floppy Disks Data Transfers in DMA or Non-DMA Mode
Parallel Seek Operations on Up to Four Drives Compatible with all intel and Most Other Mlcropro-
cessors SIngle-Phase 8MHz/4MHz Clock for UM8272A/
UM8272A-4 respectively Single + 5 Volt Power Supply (± 1COAl)
General Description
The UM8272A is an LSI Floppy DIsk Controller (FDC) Chip, which contains the circuitry and control functions for interfacing a processor to 4 Floppy Disk Drives, It is
capable of supporting either IBM 3740 single density
format (F rvi), or IBM System 34 Double Density fo rmat
(MFM) including double sided recording, The UM8272A
Pin Configuration
Block Diagram
RESET RD
WR CS
AO DBo DBl DB2 DB3 DB4 DBs DB6 DB7
DRO DACK
TC IDX INT ClK GND
VCC RW/SEEK lCT/DIR FR/STP
HDl RDY WP/TS
FlT/TRo PS o PSl
WDA USo USl HD
MFM WE
veo RD RDW WCK
DBO-7
TERMINAL . COUNT
ORO DACK
INT AD WR AO RESET
cs ___-'
READY
WRITE PROTECT/TWO SIDE
INDEK
FAULT/TRACK 0
UNIT SELECT 0 UN IT SE LECT 1 MFM MODE
RW/SEEK HEAD LOAD HEAD SELECT LOW CURRENT/DIRECTION FAULT RESET/STEP
6-3
UM8272A /UM8272A.4
provides control signals which simplify the design of an external phase locked 10QP and write precompen...
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