PC8477B (SuperFDC) Advanced Floppy Disk Controller
August 1993
PC8477B (SuperFDC
TM
)
Advanced Floppy Disk Controller
General Description
The PC8477B CMOS advanced floppy disk controller is an
enhanced version of National鈥檚 DP8473 floppy controller
The PC8477B is software compatible with the DP8473 and
NEC
mPD765
floppy disk controllers In addition it is pin and
software compatible with the Intel 82077AA floppy control-
ler The PC8477B a 24 MHz crystal a device chip select
and a resistor package are all that is needed for a complete
PC-AT PS 2 or EISA floppy controller solution
The PC8477B includes advanced features such as a
16 byte FIFO (Burst and Non-Burst modes) support of Per-
pendicular Recording Mode disk drives PS 2 diagnostic
registers for Model 30 and Models 50 60 80 standard
CMOS disk I O and additional commands to control these
new features The 16 byte FIFO will increase system per-
formance at higher data rates and with multi-tasking bus
structures This controller is designed to fit into all PC-AT
EISA and PS 2 designs as well as other advanced applica-
tions
Y
Y
Y
Y
Y
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Y
Features
Y
Y
Y
Y
Y
Pin and software compatible with Intel 82077AA FDC
Software compatible with NSC鈥檚 DP8473
16 byte FIFO (default disabled)
Burst and Non-Burst modes
Programmable threshold
Perpendicular Mode Recording drive support
High performance internal analog data separator (no
external filter components required)
Low power CMOS with manual power down mode
Automatic power down mode for complete software
transparency
Integrates all PC-AT and PS 2 logic
On chip Oscillator
PC compatible FDC address decode
PS 2 Model 30 and Model 50 60 80 diagnostic
registers
DMA control circuitry
High current CMOS disk interface outputs
Data Rate and Digital Output registers
12 mA
mP
bus interface buffers
Data Rate Support 250 300 kb s 500 kb s
and 1 Mb s
Write precompensation software programmable
68 pin PLCC package
60 pin PQFP package
Ideal for space limited applications
Functional Block Diagram
TL F 11332 鈥?
FIGURE 1-1
SuperFDC
TM
is a trademark of National Semiconductor Corporation
TRI-STATE is a registered trademark of National Semiconductor Corporation
IBM PC-AT and PS 2 are registered trademarks of International Business Machines Corp
C
1995 National Semiconductor Corporation
TL F 11332
RRD-B30M75 Printed in U S A