Re: 2445A calibration

Chuck Harris

I have been designing and debuging embedded systems for more than
40 years. I started with the 8008, and have designed and programmed
hardware for the 8080, Z80, 8085, 8086, 80188, 80186, ..., 68000, 68010,
PIC, ARM, ..... Believe it or not, but they are all substantially similar,
some a little more similar than others.

However, whenever anyone tells me that a Logic Analyzer, with an internal
disassembler probe, will ease the job of understanding anything, I know
immediately that they don't know what they are talking about.

The state of LA disassembler probes never reached a point where useful
work could be done, and are in fact a tantalizing way of wasting money.
It seems like it should be possible, was sold as the software engineers
panacea, but it never is.

The largest problem is that the disassembler probes for given microprocessors
always lags the deployment of those microprocessors, and the fast evolution of
new processors means that the art is always running away from your investment
in probes.

A far better way of understanding an assembly program is to use a
good disassembler, that allows you to use your own labels for data and
jump addresses, and it is generally free. Plus, the software interface to
the hardware processors is surprisingly slow to change, and simple and
cheap to adapt.

Software emulators, debuggers, and disassembler/decompilers, have largely
supplanted the disassembling Logic Analyzer, and they did so back in the days
of the Data General Eagle, and DEC's VAX..

I don't think anyone was recommending using 6502 tools on a 6802. I think
it was simply either someone showing a parallel, or mistaking my mention of
the 2465's 6802, for the more famous "02" processor the 6502.

-Chuck Harris

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.

IMHO, there is no need to complicate the life with 6502 tools since they'll provide no help with 6800.

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