Re: 2445A calibration

Mark Litwack
 

On Sat, Oct 13, 2018 at 08:40 AM, <maxim.vlasov@...> wrote:

6802 shares the 6800 instruction set, however for the inverse assembler for
HP/Agilent 165xx, 166xx and 167xx still a different adapter is required due to
the slightly different bus timing (or one can be made by using a simple 5V
tolerant CPLD). Mostek/WDC 650x & Motorola 680x are completely different
animals architecture wise.
The TASM PC (for DOS) cross assembler can be used to compile and link the code
natively for 6802/6800. IDA disassembler will re-create the disassmbled code
to the level of the original source (or sometimes even better documented).
HP/Agilent INVASM will disassemble in real-time all the event driven routines,
for example interrupts, insitu on the running oscilloscope.
By disassembling and recompiling the original source (disassembly done
automatically by IDA) the generated ELF (embedded linker file with symbol
data) can be loaded into the HP/Agilent 16505A or Agilent 167xx software
analyzer suite to display the statistical distribution and recurrence of the
service routine calls. This sometimes very handy to analyze the real-time FW.
I've done a few projects in the past for 68040/PPC in that way.
...

Actually, the 167xx doesn't always need a special adapter. There's a good thread on HP/Agilent disassemblers here:

http://www.eevblog.com/forum/testgear/hp-logic-analyzer-inverse-assemblers

In post #3 in that thread there's an example of using a 16702B logic analyzer to probe a 6802 processor using flying lead probes directly to the processor pins (no adapter). The thing being probed was a Tek 2465.

On the 2445A/2465A and 2465B/2465B, Tek uses bank-switched memory, making it even more fun to untangle the code. The 2465 does not have bank switching. (Maybe IDA handles bank switching?) If someone wants to head down the disassembly path, here's some info on how the banks are handled, specifically for a 2465A, but I think the B series is the same:

http://www.eevblog.com/forum/testgear/just-got-a-2465a-couple-questions/msg1469675/#msg1469675

I've done some disassembly of the code along with real-time tracing to figure out how some things work. It's time consuming and some of the code seems a bit hack-y as it was ported from one platform to the next.

-mark

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