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Questions tagged [65c02]

for questions about the 65c02 microprocessor

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4 votes
1 answer
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Can someone help me port the fat32 library used in the x16 to my homebrew 65c02? [closed]

A little background: As a retired electronics technician, (not engineer), I decided to design and build a 65C02 based computer. Only after building it did I realize how important advanced or ...
Carl's user avatar
  • 101
8 votes
2 answers
2k views

Asking explanation of 65C02 assembler code

From Gary B. Little's "Apple ProDOS: Advanced Features for Programmers", pages 176 - 188: "Since the ONLINE command handler is not inherently relocatable, all references to internal ...
mswade's user avatar
  • 93
7 votes
5 answers
1k views

Is the W65C02S TTL-compatible?

According to the Western Design Center (WDC) W65C02S datasheet, table 6-2 on p.24, Vih on all inputs is VDD x 0.7 = 3.5 V when running the CPU at 5 V VDD. This is somwhat above the level at which it ...
cjs's user avatar
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6 votes
0 answers
707 views

Transistor-level schematic of 65C02

I am looking for a transistor-level schematic for the 65C02, something like the one for the 6502 created by davidmjc (https://github.com/davidmjc/6502). I am a teacher planning to give a student ...
JRN's user avatar
  • 1,265
21 votes
3 answers
5k views

What happened to the 65832?

In his June 1985 foreword to Programming the 65816 by David Eyes and Ron Lichty, Bill Mensch expresses his hopes for a 6502-derived 32-bit microprocessor: the 65832. WDC is still thriving, but the ‘...
Jacob Krall's user avatar
  • 2,289
3 votes
3 answers
589 views

Interrupt pin type on the 6502

I have a really basic question. I have to design an 65C02-based personal computer for a school project. I have to draw my own footprint for the 65C02. My question is what type of pin is the IRQB (...
ZaharyMomchilov's user avatar
4 votes
1 answer
241 views

65C816: Inputs TTL-compatible?

New 65C816 datasheets say that Vih (for the data bus in particular) is 0.8Vdd, i.e. not TTL-compaible. Old data sheets (for example, the one published in Apple IIgs Hardware Reference) say that at 5V ...
Zane Kaminski's user avatar
15 votes
3 answers
693 views

What are the normal signals on a 65C02 in an Apple IIe?

I'm troubleshooting a dead Apple IIe enhanced, and I'm having trouble finding documentation on testing the 65C02 (as opposed to the 6502). Specifically, I've found using a logic probe that pin 6 (...
Charles Mangin's user avatar