We are debugging a pci board and met some difficulties.

[lynch]

We are debugging a pci board and met some difficulties. The main chip is,
the local device is SJA1000. We used 8-bit local bus(LAD[7:0]) as
data-address multiplex mode, and using this local bus for PCI to communicate
with SJA1000.

The difficulty I met is I can¡¯t read the register of SJA1000. I want to
know the possible cause and how to solve it. And I want to know how to
configure the ¡°Local Address Space (0~1) Bus Region Descriptor Register
Description¡±, maybe there is some wrong with the timing between the PCI9052
and SJA1000.

Thanks for your time,

lynch

 

[Dana Raymond]

You are asking us to solve a problem that may have hundreds of possible
causes without even a full description of the interface or a schematic
diagram. The bus interface of the SJA1000 is designed for 8048/8051
microcontroller or 68XX processor multiplexed address/data bus.

You mention PCI as the interface. Is there an interface block to convert PCI
or LPC to the SJA1000 bus?
If so, then that is the first place I would look. Execute a read and/or
write to address 0 of the SJA1000 and capture the cycles on a logic
analyser. If no cycle is issued, then check that your PCI/LPC interface has
been enumerated properly (memory and I/O blocks assigned to physical memory
addresses). Its also not uncommon for PCI devices (or in this case, a
bridge) to need addition configuration after enumeration (enabling memory
writes, etc.).

If you are not familiar with these issues, then you should find someone who
is within the company.

Hope this helps.
Dana Frank Raymond.