FDC3400 Datasheet | SMSC

STANDARD MICROSYSTEMS CORPORATI~ON~_ _i i ILPC FAMILY Floppy Disk Hard Sector Data Handler HSDH Features o Hard-Sectored Operation - performs all data operations o Single or Double Density Operation- recording code independent o Minifloppy or Standard Floppy patible o Programmable Sync Byte o Internal Sync Byte Detection and Byte Framing o Fully Double Buffered o Data Overrun/Underrun Detection o Dual Disk Operation - Write on one disk drive while simultaneously reading from another o Tri-State Output Bus for processor patibility o TTL patible Inputs and Outputs . PIN CONFIGURATION RD RCK RDRR ROE RDR RDL RD7 RD6 RD5 RD4 RD3 RD2 RD1 RD0 NC NC NC NC NC Vee ..../ 40 PSBS 39 WDS 38 WCK 37 FBS 36 SBD 35 RG 34 WD7 33 WD6 ':0:: WD5 WD4 11 30 WD3 12 29 WD2 13 28 WD1 14 27 WD0 15 26 VOD 16 25 WDU 17 24 GND 18 23 WD 19 22 WDR 20 21 NC PACKAGE: 40-Pin D.I.P. GENERAL DESCRIPTION The FDC3400 is an MOS integrated circuit which simplifies the data interface between a processor and a floppy disk drive. During a write operation, the HSDH receives data from the processor and shifts it out bit-serially to the floppy disk data encoding logic. Similarly, during a read operation the HSDH receives a bit-serial stream of read data from the floppy disk data separator, establishes byte synchronization by detecting the sync byte, and transfers data on a byte by byte basis to the processor. The HSDH detects data overrun and underrun conditions and indicates these conditions on its status lines. A data underrun causes write data to be written onto the disk from a special programmable fill register until new datp is entered into the write data buffer or until the wriie operation is ended. Separate read and write data registers permit simultaneous read and write operations on two different drives for enhanced system throughput. The HSDH is fully double buffered and all inputs and outputs are TTL patible. FUNCTIONAL BLOCK DIAGRAM ~g~ ~~~====~========~~========:::;-,...