Looks like I was too quick to write. @tokafondo has made the point here that the ROM can't be disabled. Oh well.

Given that, I guess I can get the system going with the WDC string in the ROM. Now to see how fast I can push the thing, given I am limited on how fast the chip can start up...

The ...

I think the MyMENSCH is more flexible than the 265SXB.

Yes, premade solutions offers limited learning potential - but not "zero" learning potential.

If someone wants to design a solution that uses cpu, memory and communications and wants to learn how to make the chips work together, a thing like ...

The problem with the 265SXB is that it's hard to work with when you want to use the included ports while accesing external RAM and UARTs.

All those pins have shared functions and while having great flexibility, it will be achieved only when working with the internal ROM.

So the solution is to have ...

This operation mode doesn't disable the internal ROM but just put the complete system in a way it can be traced from outside.

It's called In Circuit Emulation (ICE).

That I'm writing here is what I understood from emailing WDC back in the day about this very same matter.

At last, the only way to ...

I read two 6522 actually, to form a 16 bit parallel bus.

There is a document about the software this unit run, but I don't see listings there

Figure 3: Schematic Diagram of the Mathematical Function Unit. A total of 25 integrated circuits is required to accomplish the floating point and mathematical functions of a scientific calculator.

While I can't tell if that implementation is done efficiently, I found another site where they ...

It's not like we could get a MOS7529 these days, or at least easily. It was a "calculator chip" from MOS used in several calculators, providing advanced mathematical functions.

And you could make it work with a 6502

Part 1: https://archive.org/details/byte-magazine-1976-09/page/n27/mode/2up
Part 2 ...

Again, no results in a search so here it is:
https://archive.org/details/macasm-user-manual/mode/2up

A prototype coaxial cable bus communication system used in the Trend Monitoring System to interconnect intelligent graphics terminals to a host minicomputer is described. The terminals and host are connected to the bus through a microprocessor-based RF modem termed a Bus Interface Unit (BIU). The ...

A Low-Level Language for Use on the MOS 6502 Microcomputer
A low-level language, GRASSHOPPER, was developed for use as a systems programming language on the MOS 6502 microcomputer. GRASSHOPPER was designed as an alternative to assembly language for systems programming, and its use requires some ...

Right now, I have to power on, type a 'g' command (g E000) and it launches my thing. I can get it to auto-start, but it's a bit of a one-way process and if it doesn't work I'd need to take the EEPROM chip out to reset it - although I have that technology, so maybe I shouldn't be too scared...

I ...

I've kept reading about this and wondered about using a flip-flop instead of a latch. Would be of any benefit the fact that a flip-flop acts on edges and is clocked?
The latch used to generate the bank bits is a transparent latch, meaning when the latch is opened, its outputs follow its inputs. A ...

I've kept reading about this and wondered about using a flip-flop instead of a latch. Would be of any benefit the fact that a flip-flop acts on edges and is clocked?

Do a latch need a complete clock cycle to do its job?

I'm thinking about a latch, buffer or whatever, that would run at twice the clock of the system. Let's say, having a clock @20Mhz that would feed a counter, and that counter would have bit 0 feeding the latch and bit 1 feeding the CPU.

That ...

I get you, it is not a bad chip, its just locked at 8MHz and not what I need right now.

'265s starts at 32768 hz, looks for external routines to JMP to up to three times, and if not found, it continues executing internal ROM, that is able to detect several clock speeds so it can configure its ...