I finally completed the 24-bit version. This probably makes this core much more interesting as it can access 16MB of memory. It has been extensively tested and seems quite stable. See first post for download links (or go to Github).

Version 1.4 changes:
- Extended address bus from 20 bits to 24 ...

Hi,

I am trying to understand some aspect with the Arlet's 6502 core that may have been discussed before. Anyway its related to how the load_reg is set and the use of it to set write_register.

The thing is that load_reg is assigned with a non-blocking assignment (so it can be delayed). Now that is ...

EEPROMs are subject to wear-out failures. If your parts are pulls, it’s anybody’s guess as to how many erase/program cycles they have endured. Also, they may have been exposed to some ESD when they were being salvaged.

Incidentally, I have found that UV-erasable EPROMs wear out as well. They ...

Thank you both for the great work you do.

One of my friends has an Eakins Zoom 3.5X-90X Trinocular which he is very happy with. You can find it on aliexpress.

After a long time I have uploaded the latest version here. This is a fully tested version which also passes Klaus Dormann's test suite.

This version has an improved internal stack which resides in three 256-byte SRAM's. I added TOS/NOS registers so that the access is mostly 0-cycle. In the case ...

The ARM1 must be the exception that proves the rule. It did work first time - the consternation at bring-up was over a fault in the evaluation board, not the chip!

Granted, some changes were made before full commercial production began, resulting in the ARM2. These would have been in light of ...

From wiki there is this sentence:
At the same time, these visits invariably resulted in the engineers he (Peddle) presented to producing lists of required instructions that were much smaller than "all these fancy instructions" that had been included in the 6800.
I would think that they intended ...

Well, I don't have a ATF750, but one of my programmers says it can program ATV750 which seems to be quite similar (according to datasheets). The programmer is a BP soft CP-1128.

Anyone knows if the ATV750 is compatible with the ATF750? If anyone has a ATF750 to spare I can test it.

I have been using the https://www.ti.com/lit/ds/symlink/txb0108.pdf for some years and haven't had much problems. I even used it to interface a NMOS 6502 some years back(!). The address bus don't need it.. I used the 245 there.

Anyone tried to overclock the 65C02? E.g. driving it at higher voltage ...

Someone was trying to figure out what the flash sequence means, and according to my old notes this is what happens:

----chop-chop-----

The 8050 routine is slightly different. First, its not as condensed as the one from the 2040. For example, the original starts with an LDX #$FF, uses this, then ...

Just to add a small note:

I recently used a 7555 timer (ICM7555IPAZ-ND) that uses just a few microamps of power.

If you want a circuit with an external timer to punch the 65C02 RDY signal, this nicely lines up with WAI to reduce the total system power usage.

You may want to remove the ...

I also asked it if a loop may help to ensure that position above 2 can be used, and a way to make the answer 32-bit. And to add enough ASL and ROLs. This is the code it gave:

lda #ascii_value
sec
sbc #0x30
sta temp_low
lda #0
sta temp_high
lda #position
sec
sbc #1
sta position

loop:
asl temp_low ...

I asked Google Bard to make a similar routine and it responded with similar code. Lots of faults, but interesting enough it corrects itself when you point out those faults (I only tried a couple).

I then asked it to mathematically express the transformation and it gave this result:

decimal_value ...

Identifying which version of Microsoft BASIC was used as the base might be possible - the addresses in the labels give very strong clues (the difference between two tells you how many bytes of code were originally between them) - but would require considerably more work than I'm willing to put in ...