Specifications
33
EPC-30 Hardware Reference
Page 40
Hard Drive and Floppy Disk Drive Controller
A floppy disk drive controller is contained in a Super-I/O chip, the
FDC37C665GT, manufactured by Standard Microsystems Corp. For details
of the operation of these functions, refer to the SMC datasheet for this
device. Note that this device also contains the two serial ports and one
parallel port; see below.
The floppy disk controller uses programmed I/O mode; DMA operation is
not supported. This makes it incompatible with some operating systems that
don’t use the BIOS for floppy support. The EPC-30 supports one or two
5.25" 360KB and 1.2MB as well as 3.5" 720KB, 1.44MB, and 2.88MB
drives and media. The floppy controller occupies I/O addresses 0x3F2,
0x3F4, 0x3F5, and 0x3F7. It uses the AT bus interrupt IRQ6. Connection to
a floppy disk drive is made via an “untwisted”
34-pin ribbon cable. NOTE: The EPC-30 by default will supply power to
the floppy disk drive using the untwisted cable and a fuse. Configurations
that do not supply power through the cable (those pins are instead grounded)
are available.
The IDE hard disk interface is provided by the R380EX. The IDE hard disk
is mapped to I/O addresses 0x1F0 - 0x1F7, 0x3F6, and 0x3F7. Note that I/O
address 0x3F7 is shared with the floppy disk controller as required for PC
compatibility. The IDE interface chip selects ~HCS0 and ~HCS1 are
generated by R380 chip selects. ~HCS0 corresponds to CS3, and ~HCS1
corresponds to CS1.
The IDE hard disk uses AT-bus interrupt IRQ14. Connection to an IDE hard
disk is made through a standard 2mm pitch 44-pin ribbon cable header
mounted on the PCB. This interface is designed to support 2.5’ drives that
take power through the cable. Up to two drives are supported by the IDE
interface.
Serial and parallel ports
The EPC-30 contains one PC-compatible parallel printer port and
up to three
PC-compatible serial ports (COMA from the Intel386 EX and
COMB/COMC from the Super I/O). The COMB and COMC serial
ports from the Super I/O include NS16C550-compatible UARTs to
support high-speed operation (including 16-byte FIFO as default).
The COMA serial port in the Intel386 EX is NS16C450-
compatible.