[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
RE: pci9080 chip
One possibility is the serial eeprom may be loading garbage into the chip
causing all sorts
of problems, although from your message it's not clear if you have one
installed or not.
If you do, consider disconnecting the serial eeprom data output
pin(temporarily) by desoldering if you have to.
The 9080 EEDO pin has an internal pullup. It decides a low on EEDO is an
eeprom start bit, so by this mod,
you guarantee the 9080 won't see an eeprom and will reset to some "normal"
default values, which ought to
let your PC boot.
If this all works, then your eeprom likely has bad values in it. Note that
the 9080 is "supposed" to
automatically detect if the eeprom is blank (all 0xffff) but in my
experience it doesn't work.
I always add a pullup resistor to the eeprom CS pin, and a board jumper that
lets me disconnect the 9080
EECS pin, therefore causing the 9080 to not see the eeprom and use default
values. I boot up with
the jumper pulled, then put it back on while the power is up. This lets me
reprogram the eeprom using their
PLXMON or our homegrown software even when the eeprom is loaded with bad
Hope this helps!
From: Harkema, G.A. [mailto:G.A.Harkema@tue.nl]
Sent: Wednesday, July 26, 2000 10:45 PM
Subject: pci9080 chip
we are developing a PCI board to controll a data aquasition system. On
the PCI board is the PCI9080 chip. On the local bus of the PCI9080 is
only a I/O controller whitch is implemented in a FLEX7000 EPLD from
Altera. There is no EEPROM placed on the board. We are using the PCI
chip in "C mode". Local bus input signal lines have the following signal
ADMODE = VCC
BIGEND# = VCC
BREQ = GND
DREQ[1:0]# = VCC
LRESETI# = VCC
NB# = VCC
S[2:0] = GND
WAITI# = VCC
BTERM# = VCC
LLOCK# = VCC
LHOLDA = GND
EOT0# = VCC
EOT1# = VCC
READYI# = VCC
LINTI# = VCC
All tri-state I/O pins except LD[31:0], LA[31:2] and LBE[3:0]# have a
pull-up resistor to VCC (10k), all tri-state I/O from the EPLD is
All PCI bus signals are connected to the PCI bus (PCI bus = 32 bit, 33
MHz, 5 V).
The local bus clock frequency is 20 MHz.
When booting the computer system we see the following:
LRESET0# goes low for about 160 ms.
After this the EESK clock starts and the EECS goes high.
After 11 EESK clocks EECS goes low and after 13 EESK clocks EESK stops
??? what is happening according the datasheet of the PCI9080, page 117,
EESK is a continous clock ???
During EEPROM initialization the PCI9080 respons on the PCI bus as a
??? according the datasheet page 14 is should respons as a retry ???
After a while (we dont now how long) the respons to the PCI bus is a
retry, and the computer system hangs (in the boot sequence).
??? why is respons of the PCI9080 chip to the PCI bus a retry, the
EEPROM is not loaded and the NB# pin is connected to ground ???
Please help us.
Gerard A Harkema