EPC-3307 Hardware Reference
60
In 100BASE-TX mode, the analog subsection of the PHY performs two functions:
•
Converts a received analog data from the RD pair into a digital 125 Mbps
stream, recovering both clock and data.
•
Converts a digital 125 Mbps stream into the proper format and drives it
through the TD pair into the physical medium.
The 82559 defines a maximum distance of 25.4 mm between itself and the
associated magnetics, and another 25.4 mm distance between the magnetics and the
RJ45.
Battery
The 3.0V lithium battery supplied with the EPC-3307 and mounted on the CPU
board is a Renata CR2032 “coin cell” or equivalent. Should the battery fail, you
may obtain and install a replacement. For information about replacing the battery,
see
Replacing the battery
on page 10
.
The battery powers the CMOS RAM and TOD clock when system power is not
present. If system power is present, the +5V voltage also powers the CMOS RAM
and TOD clock. This is done with the +3.3V isolation diodes, so that either the
onboard battery or the +3.3V power supply voltage can supply power and neither
power source affects the other.
The battery has an expected battery life of 2 years on continuous battery power. In
a system that is powered on much of the time and where the ambient power-off
temperature is less than 60°C, the battery is estimated to have a life of 10 years.
Super I/O
The National PC87309 Super I/O controller provides floppy controller, parallel port,
serial port, and a keyboard and mouse controller functions. It interfaces through the
ISA bus and requires external decoding of the high-order address bits for full 16-bit
decoding required by PC95/PC97. It uses a 48MHz clock. This design does not use
the chip’s parallel port features.
Floppy disk
The floppy controller device resides inside the Super I/O chip and is accessed at the
standard PC I/O addresses 3F0–3F7h. Floppy interrupts are signaled on IRQ6.
The floppy signals connect to a header on the CPU board, allowing ribbon cable
connection of a floppy disk drive. Power is provided to the floppy disk drive
through the cable.
The Intel specification for distance from the PHY to the magnetics must be
violated in this design since the magnetics reside on the RTM near the RJ45.
Write down all CMOS setup parameters while the battery is still good, or save
them using the options available on the BIOS configuration’s
CMOS Save and
Restore sub-menu
.
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com