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17

In the 1988 Report on the 65c832, Mensch described the 65c832 as a back-burner project with an uncertain timeline: Since WDC is not a gigantic conglomerate, it has limited resources. If all your manpower, time, and money are going towards the development of the 65c265, you don't have any left for the '832. That's exactly what was happening ...


7

65C02 is a CMOS version of 6502 (which was NMOS) chip. Judging from Wikipedia articles on these chips and few of the datasheets I found, it seems like it should work exactly the same way it did on 6502, i.e. held high during normal operation, pulled low to fire an interrupt. Are you sure it is not connected to anything? I'm not too familiar with Apple ...


7

I suppose you have heard of the draft datasheet of the 65832? https://downloads.reactivemicro.com/Electronics/CPU/W65C832%20CPU%20Datasheet%20v2.0.pdf Apple was the main customer of the 65816 (for Apple //gs) which needed to be compatible with 6502. They had no need of a 32bits version as Macintosh had already chosen the MC68000 family which is a sounder ...


5

The W65C02 data sheet does explain it (p. 9): 3.4 Interrupt Request (IRQB) The Interrupt Request (IRQB) input signal is used to request that an interrupt sequence be initiated. The program counter (PC) and Processor Status Register (P) are pushed onto the stack and the IRQB disable (I) flag is set to a "1" disabling further interrupts before ...


5

I've been meaning to get around to this for ages, sorry. Tonight I stumbled across SAMS COMPUTERFACTS for the Apple IIe which I had downloaded from the Internet Archive. Here is the logic chart data for the CPU (IC UC4) from page 27. I've rearranged it for clarity. Pin 6 should be high, as you say. (Note: I haven't verified this data on real hardware yet.) ...


4

At some point before 1990 the idea seems to have first surfaced as a 'report' about 6502 chronology and future processors might suggest. It includes not only information about the ghostly 6516, but also information about a 65832 which should have more features than the datasheet showed. There was also no substantial follow up. The project might have gotten ...


4

Are old 65C816s TTL compatible? If their Vih is 2.0v, they are certainly TTL-compatible. Was there some kind of change? All WDC chips seem to be verilog-reimplemented, so when they synthesized them into netlist, they've intentionally dropped TTL-compatibility of IO-pins. The reason for that might be the need to have chips working in 1.8V..5.0V range (...


3

The interrupt pin is an input.


1

An interrupt pin of a CPU will always be an Input. After all, it's whole purpose is to tell the CPU about an interrupt pending. Wouldn't work if it's an output, would it?


1

Who made your 65C02? Was it WDC? If it's WDC, then there are a few pins that should be held high with a 3.3k pull-up resistor. Such as the BE pin which is only on WDC versions. BE (Bus Enable) should be pulled up. Some example taken from http://wilsonminesco.com/6502primer/MysteryPins.html VPB (or VP): With WDC's 65c02, leave it unconnected. With ...


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