27 Jan
2012
27 Jan
'12
8:56 p.m.
fixed (I probably use my Fluke for testing memory more
than any other
single thing - even back in the day, a "DMA test" for a COMBOARD was
really just running a memory test on the quadrant of 68K memory space
that caused Qbus/Unibus DMA transactions... we could test local ROM,
local RAM, or remote RAM via DMA, all with the same buttons and the
same tool). Fortunately, I have a 6502 pod as well as a 68000 pod, so
the Fluke has plenty of targets at my house.
Rignt.... I sued to wish fo the 'right' test gear for every problem, then
I realised you got a lot more done using what you have :-)
Yes... there are other ways to run address testing,
bus testing,
etc... they are more work than popping the processor, plugging in a
vintage purpose-built tester and hitting well-understood buttons. The
lack of a Z80 pod pushes this project further down the stack,
especially since I have little software for the M3 that requires more
than 32K.
I think i'd start witha loop (in BASIC or machine code) that accesses a
location in the top 16K of RAM and check that all the address, data, RAS
and CAS pins to these RAMs are toggling (just iwth a simple logic probe).
You'll pick up sillies like a defecctvie driver IC that way.
-tony