Description
National Semiconductor Corporation – NSC DP8473V DP8473 Floppy Disk Controller PLUS-2
This controller is a full featured floppy disk controller that is software compatible with the mPD765A but also includes many additional hardware and software enhancements These enhancements include additional logic specifically required for an IBM PC PC-XT PC-AT PS 2 design This controller incorporates a precision analog data separator that includes a self trimming delay line and VCO Up to three external filters are switched automatically depending on the data rate selected This provides optimal performance at the standard PC data rates kb s and s It also enables optimum performance Mb s (MFM) These features combine to provide the lowest possible PLL bandwidth with the greatest lock range and hence the widest window margin This controller includes write precompensation circuitry A shift register is used to provide a fixed 125 ns early-late precompensation for all tracks (83 ns for or a precompensation value that scales with
Features
Fully mPD765A and IBM-BIOS compatible Integrates all PCXT PCAT and most PS 2 Logic On chip 24 MHz Crystal Oscillator DMA enable logic IBM compatible address decode mA mP bus interface buffers 48 mA floppy drive interface buffers Data rate and drive control registers Precision analog data separator Self-calibrating PLL and delay line Automatically chooses one of three filters Intelligent read algorithm Two pin programmable precompensation modes Other enhancements Mb s data rate Implied seek to 4000 tracks IBM or ISO formatting Low power CMOS with power down mode.
Plastic Leaded Chip Carrier Dual-In-Line Package
TRI-STATE is a registered trademark of National Semiconductor Corporation is a trademark of National Semiconductor Corporation IBM PCXT PCAT and PS 2 are registered trademarks of International Business Machines Corporation C1995 National Semiconductor Corporation F 9384. the data rate 250 ns for data rates kb s respectively Specifically to support the PC-AT and PC-XT design the Floppy Disk Controller PLUS-2 includes address decode for the A2 address lines the motor drive select register data rate register for selecting kb s Disk Changed status dual speed spindle motor control low write current and DMA interrupt sharing logic The controller also supports direct connection to the mP bus via internal 12 mA buffers The controller also can be connected directly to the disk drive via internal open drain high drive outputs and Schmitt inputs In addition to this logic the DP8473 includes many features to ease design of higher performance drives and future controller upgrades These include Mb s data rate extended track range to 4096 Implied seeking working Scan Commands motor control timing both standard IBM formats as well as Sony 3 5 (ISO) formats and other enhancements This device is available a 52 pin Plastic Chip Carrier and a 48 pin Dual-In-Line package
Manufacturer:National Semiconductor
Datasheet:TI/DP8473V.pdf
