NMOS 6507 stuck at $37FF after reset

[SuperBIOS]

I am building a SBC using an NTE6507 (rebadged NOS NMOS 6507). However, whenever I reset the 6507, the address lines get stuck at $37FF according to my logic analyzer. My reset circuit is a pull up resistor and a button, no debouncing capacitor (I do not think this is the issue as my oscilloscope does not show a bounce). Is there a solution to this problem?

[floobydust]

First, welcome!

Second, that's a pretty vague bit of info. It would much easier anyone to assist if you could post a proper schematic of what you've built and an idea of what code you've written to get the processor to do something, or at least some sort of NOP wiring of the databus.

[BigDumbDinosaur]

SuperBIOS wrote:

I am building a SBC using an NTE6507 (rebadged NOS NMOS 6507). However, whenever I reset the 6507, the address lines get stuck at $37FF according to my logic analyzer. My reset circuit is a pull up resistor and a button, no debouncing capacitor (I do not think this is the issue as my oscilloscope does not show a bounce).

Could you please post a complete schematic (monochrome) so we can look at the entirety of your design?

Quote:

Is there a solution to this problem?

I’m reasonably certain there is. Looking at your schematic should enable us to help you find the solution.

[BigDumbDinosaur]

floobydust wrote:

First, welcome!

Second, that's a pretty vague bit of info. It would much easier anyone to assist if you could post a proper schematic of what you've built and an idea of what code you've written to get the processor to do something, or at least some sort of NOP wiring of the databus.

You read my mind!

[Dr Jefyll]

[Edit: echoing other posts, but here goes... ]

Welcome, SuperBIOS

There are lots of folks here willing to assist, but first you need to assist us by providing more information, notably including some photos of your project (these can be attached with your post) and preferably also a schematic.

Also, what's the clock arrangement for your 6507? It's not usual for a 65xx CPU to get stuck at $37FF or any other address, so circumstances (including the clock and power supply) need to be examined.

Please be as forthcoming as you can about any and all details that may seem relevant; also your level of experience and whether you have access to other instruments such as a DMM and/or oscilloscope. This may seem tedious to but I promise you it's the most expedient way to get your project on track. Cheers!

-- Jeff