Apple II Schematic error about bit-preserve

[baldengineer]

FYI, It looks like the original submitter for the Apple II and II+ schematic either re-used the design or heavily based on the II+ on the II.

I didn't realize that when I looked closer at the II+. So, I have put significant work into repairing that schematic. My plan was to "back-port" that one to the II design later.

We'll take feedback on either! But if you are doing a deep dive review, the II+ might be a better choice since it's a bit more active and has already had a number of corrections.

[reifsnyderb]

Sounds good. It's a process. :-)

Also, I suspect the "INH" signal to inhibit the ROM from the expansion slots isn't tied to +5v...and should be. I haven't confirmed this yet, but have been unable to find the hold-up resistor.

I really started with the II as I am exploring the possibility of an Apple II board using readily available electronics. i.e. Use a single SRAM chip instead of 24 DRAM chips.

[baldengineer]

For the most part, the only significant difference between the II and II+ (in terms of hardware) is the ROM. There were other minor changes, but the vast majority of the chips are the same.

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On Mon, Jan 8, 2024 at 4:11 PM reifsnyderb ***@***.***> wrote: Sounds good. It's a process. :-) Also, I suspect the "INH" signal to inhibit the ROM from the expansion slots isn't tied to +5v...and should be. I haven't confirmed this yet, but have been unable to find the hold-up resistor. I really started with the II as I am exploring the possibility of an Apple II board using readily available electronics. i.e. Use a single SRAM chip instead of 24 DRAM chips. — Reply to this email directly, view it on GitHub <#125 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAFPXXC52AIP4QITTBNKVQLYNRVK3AVCNFSM6AAAAABBSB3FYCVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMYTQOBRHEYDENZQGM> . You are receiving this because you commented.Message ID: ***@***.***>

[baldengineer]

Addressed in 2e13763 for the II+ schematic. The II schematic will get "fixed" when in a future effort.