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IF you are reading this and would like to add feedback to the modem topics! Garth Wilson has created a new thread regarding those topics!!
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Ok my biggest issues - well almost my ownly issue is the form of rom that I'm going to use!

** I was thinking e2prom since you dont need ultra violet to reprgramme but I'm not sure hmmm.

there is a eprom programmer "dicksmith" is selling now for $112 new zealand dollars as a professional kit - does this sound reasonable, programmes nearly all eproms and nicely controlled in software.

What are some of you guys using as roms? + programmers?

I dont want to concentrate too much on the programmer (rom side of things).

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NPastoll

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http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

Gee's I think for someone starting out I think I might have a good deal money wise:-

Looking at the costs of those professionally sold programmers I think I will think about buying this eprom programmer kit for $112 nz dollars.

means I dont need to buy a pro one and I get the experience of building a programer professionally - if it lives up to its name, which I'm finding out about!

thanx for the replies

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NPastoll

Hi Garth,

I have a Needham's programmer as well, the EMP-11. This version plugs into the parallel port of the PC. In addition to all major types and sizes of EPROMs, it also does Flash, PAL/GALs, and PIC microcontrollers. It was expensive, but like anything else- you get what you pay for. I've used various Needham's programmers at work over the years and I have been very satisfied with them.

eBay is a good place to find cheap device programmers.

Regards,
Mike

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- Mike Naberezny (mike@naberezny.com) http://6502.org

Do these commercial programmers also support flash ROMs as well? I imagine it would be very inconvenient to have to program, reprogram, and reprogram again EPROMs in the course of debugging the software.

I suppose that one could use an emulation of your circuit now-a-days (even if you have to write it yourself). However, while I was working for Hifn, sometimes we'd have code that works fine in our MIPS emulator, but which crashed in the real circuit. Fortunately, we had flash ROMs to work with.

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Samuel A. Falvo II

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

Eventually, something, somewhere, is going to be needing a ROM. EEPROMs apparently are currently the most popular method of talking to CPLDs and FPGAs, for precisely the reasons you state.

However, I am looking more for the boot-time code storage.



It sounds nonsensical, but I've experienced this first hand. It can take pretty significant effort to get even this kind of minimal bootstrap code working in an embedded circuit, especially when dealing with those uber-configurable UARTs that can handle everything from RS-232A to 100-base-T Ethernet (like some of the 68xxx-series microcontroller UARTs can). Of course, this isn't likely to happen with a 65xxx-type system, especially if you just stick with 6551 UARTs. Remember also that the data transfer protocol will also need to be verified as well.

What's funny is that my roommate laughingly suggested that I use a paper-tape solution to boot-strap the computer with. I actually like the idea -- on the one hand, it does complicate the circuit a tiny bit, as I need to make a paper tape reader, but on the other hand, it sounds so anachronistic that it is probably the coolest thing most people will ever see. But there's no argument -- I won't have any need at all for ROM in such a system.



I wasn't talking about a ROM emulator. I was talking about a hardware emulator (e.g., VICE under Linux will emulate a Commodore 64, 128, VIC-20, PET, etc. to an *AMAZING* level of detail. It even emulates the bugs and gotchas in the VIC-II chips that enables those weird video modes/effects!) -- a software model of your whole system, including the CPU, and its baseline set of peripherals.

--
Samuel A. Falvo II

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

STOP IT! You're lending credibility to the technique!

In all seriousness, though, it should be rather easy to do. I envision a system where I have 8 rows corresponding to the eight data bus pins, and two command rows that basically provides the self-clocking necessary to load the software with.

Because two bits are reserved for the command, the commands would read similar to this:

00 - No operation -- the default command when no paper is loaded as well.
01 - Load address low register
10 - Load address high register
11 - Store data to current location; increment address register

Tapes are created by printing onto 8.5"x11" paper sheets using any black-ink printer, and each page is cut into strips, which are then spliced by hand. Because there are no holes punched, there is no paper waste. The presence or absence of ink is detected using LEDs and photodiodes.

Each "tape transaction" consists of setting up the datum first, issuing the command, then releasing the command before moving to the next datum. In binary, it would look like this (storing the characters 'A' and 'b', starting at the current address location):

yeah more like a barcode version of punch carding!

sounds very interesting actually and quite straight forward in simple terms, you'd be creating a hell of a design wouldn't you?! for those tape motors and sensors, Hehe and what about the controller card!

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NPastoll

My design lacks tape motors -- the tape is drawn through by hand. That's why I have the command bits set up the way I do. Lack of motors means vastly simplified hardware, and a minimal Forth interpretter would probably fit on a reasonably sized strip of tape. It's not like I'm filling all of 16MB of memory with code.

As far as the "controller card" is concerned, it'd be a simple bus master. A toggle switch on the front panel of the machine would probably disable the CPU, so there isn't even the overhead of DMA. Simple, sweet, and to the point. Minimum complexity.

But, of course, I'll probably end up spending more on this than a simple, home-brew EPROM programmer and commercial EPROM eraser combined. Or I can make my own EPROM emulators by using a 62256 or 6264 SRAM chip backed by its own battery, and programmed off the PC via the parallel port. To be honest, this sounds like the best way to go.

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Samuel A. Falvo II

Why not keep the paper whole? I've seen plans for a poor-man's scanner built from an old dot matrix printer. You simply attach the IR LED/Receiver to the print head via a flexible cable, and let the printer do all the mechanical work for you. It also can print (save) or scan (load). To load, just send a series of spaces and carriage returns. Most dot matrix printers have a "home" position detect switch that can be used to start a timing loop to perform the reading of the IR detector.

You could print a whole line of either " " spaces or filled blocks (chr$(219) in the old DOS days). That way you can get about 8 bytes per line roughly after the overhead.
If you go with the dot mattrix printer, you'll also be able to use the old box of continuous paper. No cutting required!

Of course, there are some very simple cassette tape storage formats to consider. Also, Flash memory is quickly becoming economical.

Good luck!

Daryl

Too clumsy, and dot matrix printers are all but impossible to find here. Also, I know of at least one dot matrix printer (it's a Star Micronics printer, but I forget the exact model) that was smart enough to not budge the head on a line full of spaces.



That's why I asked about the ability to program flash ROMs in an EPROM burner, to which I still haven't received a reply. That being said, I hadn't considered audio cassette storage. And it'd be a heck of a lot faster to load than paper tape. I could throughputs approaching 1200 to 1500bps with it.

Thanks for the suggestion. I'll have to tinker with the idea some more.

--
Samuel A. Falvo II

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

some great ideas on this thread - hehe nothing to do with my origional post but good!

yeah I can get a hold of a great kit which I can build fairly cheaply - and which programs most eproms.

but getting ahold of a uv eraser is not looking good at the moment!

I mean I could replace the eprom for my first project with memory emulated via serial port but thats really far to slow as we all know - memory backed up by battery is promising!

anyone got any ideas on battery backed up ram!?

if I could get ahold (eraser)- even if I knew someones in the area that I could use from time to time - i'll find out!

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NPastoll