6502.org

Cypress-25

leepivonka wrote:

The Ben Eater 6502_monitor.ino program will probably be much too slow to keep up with a 100KHz (10usec period) or faster CPU clock. I think it is intended for use with much slower clock rates.

That’s probably the issue. When connecting some LEDs to pins A15 and A14, they flash as expected.

Cypress-25

tmr4 wrote:

What clock speed are you using? It's likely the 6502 you're using isn't stable at that speed.

Using a 1MHz Crystal oscillator connected to phi in.

Cypress-25

Hello!

So I'm just starting out with 6502s after a long while, and I'm getting some strange results.
I'm using a modified version of the arduino code Ben Eater used output. (Just changed the pin numbers)

The address jumps around despite a NOP being shown.

The resets also seem to be working ...

Cypress-25

Okay, I'll be sure to read up on them.

Thanks so much for your help!

Cypress-25

I'm very new to the world of ICs so I'm unfamiliar with the meaning of the numbers on the top of the chip.
Anyway

I got a 6502 (not the CMOS version if that helps) chip from a local store with the markings
C014377
R6502-34
8230 (logo)
On it. All I've gathered is that it is a Rockwell chip, and ...

Search found 5 matches

Re: Strange NOP results

Re: Strange NOP results

Strange NOP results

Re: Possible fake Rockwell chip?

Possible fake Rockwell chip?