John Bell 6522 VIA Card on an Apple IIe Enhanced

[groinksan]

Aloha! Total newbie here!

I took out my John Bell 6522 card from storage to test. I have an Apple IIe enhanced, DOS 3.3, and the 6522 card in slot 1. I'm using the following document as reference:

https://archive.org/details/JohnBellEng ... d/mode/2up

Although the document references slot 3, I'm using slot 1 in case my IIe's slot 3 is hard-coded for the auxiliary slot. I've assembled the code to reference slot 1. I've also placed a wire jumper between T1 and T2 as instructed by the article (pins 7 and 8 on J2 for those following at home.) The 6522 is the real deal - a plain Jane SY6522.

The article demonstrates the 6522 functionality by using it as a clock. The article for this utility starts on page 8.

The problem I'm running into is that the interrupt service routine does not appear to execute. The way the code works is that, initially, it implements a interrupt service routine, by pointing the interrupt vector at $03FE to the routine at $02B0, and then exits. And then the Apple II is supposed to constantly execute the routine by interrupt, which basically refreshes the time on the screen with the hours, minutes and seconds.

I noticed that this article was written in 1982 - one year before the introduction of the Apple IIe. Therefore, I'm wondering if this interrupt method does not work properly on an enhanced Apple IIe. I don't have a II or II Plus to test this theory. I also have two of the John Bell cards, and same problem on both.

[barrym95838]

It appears that cards designed for the ][ and ][+ don't necessarily play nicely with the IIe. Here's an example, which may or may not be helpful, but at least illustrates the point:

http://www.1000bit.it/support/manuali/a ... ie.08.html

I'm left wondering if there's a standard way to "register" a new interrupt on an enhanced IIe ... I don't know, because the majority of my experience is with the ][+, which hardly ever used interrupts in the configurations with which I'm accustomed.