UM8272A

(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...