What a terrific thread this is turning out to be Squonk! It's wonderful to see this survey take shape, and to follow the journey as it evolves. I'll continue to read with interest.

Regarding Elmore delays, they do seem to be a useful model here. It's worth noting that the actual delays I observed ...

Quick update:

Version 1.1 of the 65816 test suite is now complete. This new version takes four passes through all opcodes to test both zero and non-zero values for the DL and DH registers in turn. The code works perfectly on the Logisim model, including adding extra cycles when needed and saving ...

I couldn't imagine doing this without a model and a test suite. Many bugs were uncovered by exercising the model manually first, and then with the test suite.

I'm working on the DL = 0 microcode this morning. I thought it might be tricky to detect DL=0 and change microcode on the fly, but not so. I ...

I’m happy to report that hoglet and BigEd were able to confirm the validity of the 65816 test code.

After a few intercontinental bug-fixes of both the test code and the Logisim model, the 65816Test ran successfully on the Beeb816 (a 65816 BBC Micro accelerator by BigEd and revaldinho), on the ...

The block diagrams are terrific and complement the Logisim model nicely. Thank you ttlworks!

On other news, I’m happy to report that the model just completed its first full test. The test exercises the microcode for all opcodes using E = 0, X = 0, M = 0, D = $5001, S = $6fff, and tries to check ...

Hi Daryl,

I'm using the Kowalski emulator to write a test suite for the C74-100 's 65816 features. It's all been working very well. Thank you.

In running through the opcodes, I did note that PHB and PLB are incorrectly documented as pushing and pulling the B accumulator. In fact the opcodes push ...

Technically, I have an 816 (in the form of a beeb816 - see thread and presentation ) Beeb816 Revival: AND THIS TIME ... IT WORKS . :mrgreen:

The beeb816 looks like a fantastic project Ed, congratulations. It looks like there were some early synch issues that you managed to resolve. Very ...

Yes, that's true. I'd be happy to share the code of course.

I wonder if someone with access to a working 65816 might be interested in collaborating a bit on this. I could use some help coming up with a list of tests to exercise boundary conditions, as well as in validating that the code runs ...

I have completed "unit testing" on the current model (by which I mean that every instruction has tested correctly at least once). Did I really say this? Hmmm ... based on the bugs my test suite is uncovering, I can categorically say this was NOT accurate.

On the other hand, the kinds of bugs I'm ...

Thanks Andy. I’m fast becoming a fan of the 65816 myself. Picking up a 16-bit value in the accumulator and shifting it left will make a convert out of anyone; or how about indexing across 64k with a single register. I have a sentimental attachment to the NMOS 6502, but I have to say that programming ...

Thanks for dropping by Andy. I should have been more clear in the explanation of how all this is working ...

This CPU will allow you to select the instruction-set you want for Emulation Mode. The choices are NMOS 6502 or 65816. The default selection is made via a dip-switch, which is currently ...

I'm excited to share below the first snippet of 65816 code the model has run.

The CPU boots in "NMOS Compatibility Mode". The $02 NMOS opcode (normally a KIL or JAM undocumented opcode) has been replaced with the XCE instruction. The "CLC, .BYTE $02" sequence therefore switches the CPU to Native ...

These are great Plasmo. Thanks for sharing!

I was saved from a similar fate by a comment I read somewhere about using a scale-accurate printout of the PCB to check all the footprints prior to sending the Gerbers off.
That might have been me who advised that. That seems to me very likely BDD. I recall studying your POC units carefully, and ...

I was saved from a similar fate by a comment I read somewhere about using a scale-accurate printout of the PCB to check all the footprints prior to sending the Gerbers off. It's also helpful in making sure the housings of connectors and other gadgets don't step on each other, which is unfortunately ...