I found a Non Volatile SRAM on Digikey:

Part number 296-9391-5-ND

The Datasheet is here:

http://focus.ti.com/lit/ds/symlink/bq4011.pdf

http://datasheets.maxim-ic.com/en/ds/DS ... 1225AD.pdf

http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2646/t/al

I get mine as samples. I've had so many free chips from Dallas/Maxim.

They come up to 2Mx8, but a problem with all of these is that they're not very fast. I think 70ns is the fastest I've seen. The lithium battery in many of them is not replaceable either. I made my own circuit for battery backup 20+ years ago, with write protect during power-down and -up. It took a lot of inexpensive components. I suspect that now there are ICs to do the job, but I haven't looked.

I'm looking at it as a quick and temporary way to design where I can come back to my code without having to re-enter it. I also heard the data in one of those chips won't survive a cold reset. If they last 20 years then I will probably be off to something better. I'm sure there are better ways to do this and I welcome suggestions.

What I think I need is a parts list of things I need to make an advanced 6502 or 65C816 system and I'm working on it. If there was a complete list and if it could be bundled with a $1.50 prototyping board from Futurlec or use a cheap breadboard then it would be an inexpensive kit to promote 6502.org which would expedite learning. It has to be cheap and advanced. It is hard for me as an old C-64 user to get back into because I didn't go the hardware route. But I like and I'm thankful for the users here on the online tutorial of making a bootrom and I think there needs to be a getting started kit tutorial for beginners.

This is something I may do this summer and I'm looking at a 128 X 64 graphics LCD to program with some microcontrollers first.

http://www.futurlec.com/ProtoBoards.shtml

If it's for beginners, it can't be very advanced. If you just want a realatively easy mass storage that's cheap though, you can get a 24cXXXX-series I²C EEPROM (available up to 128KB or 256KB now) or a multi-megabyte SPI flash memory. They both come in 8-pin ICs for just a few bucks each, meaning they're good for holding the cost down. They're easier to connect (since they have so few connection lines) and they don't need a back-up battery. The I²C EEPROM's instructions for storing and retrieving data are somewhat simpler but it's not as suitable for transferring large amounts of data fast. The I²C interface (which can be used for other things at the same time too, like a real-time clock, data converters, etc.) will need two pins from your 6522 VIA. One will be clock and one will be bi-directional data. (After a "start" condition, the initial data transferred tells which device the controller will be talking with; so there's no need for separate chip selects.) The SPI needs three lines (which are bussed) plus a separate chip enable for each chip you want on the interface. There's clock, data in, data out, and chip select.

I believe you are right but in order to create more interest, 6502 based systems have to offer a number of features and abilities. A 6502 based system has to become more Arduino like and maybe libraries have to be created for that.

The Commodore patents have listed the manufacturing processes which have changed and they have expired so I'm also wondering if an FPGA can be made like the Vic chip. Would even the Vice team be willing to make something like that?

Will the Microchip Erasable PROM work?



I'm not experienced but I want to thank you all for your time.

Have a look at the DS1210.

Thanks. That's the ticket.


They're all serial, so you can't just connect them directly to the processor bus; but yes, I have used the 24LC256 I²C EEPROM you mention. I had forgotten about the 64-byte page write, which speeds up the writing of large quantities a lot. (I wrote my software years ago and then I forget what's in it and just use it.) I made these half-postage-stamp-sized EEPROM modules with the 8-pin DIPs:

That's a 4-pin socket on the right end, to fit onto a 2x2 header of .025" square posts. The shorting bar on the left is on a 1x2 pin header for write-protect. The LED tells when it's powered down so you can unplug it from the computer board, although this is just the first of many I made and after this first one I put LEDs on the computer to show the status of the I²C power and clock lines.

I intend to make other small I²C modules that can be plugged into the same socket, with an RTC probably being next, just to try it for a future project. My workbench computer keeps time in a software RTC, but a few applications require turning it off. So far I haven't needed the RTC running during those times, but of course if I turn it off and on, the actual time of day won't be accurate. It's mostly used for timing processes though, not so much keeping time of day and calendar.

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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?

There is also the FM1808DS by RAMTRON. They don't use batteries and in my tests are drop-in complatble with regular SRAM with the 'standard' pinout.

Only 70ns access time though, so okay for development at lower clock speeds.

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Bill

I was looking at the William programmer at:

http://www.sivava.com/index.html

and it said that it does the DS1220 but no mention of the DS1210.

Where do I find a programmer for it? The cheaper the better.

I didn't see any chips with the "ds" designation on them.

http://www.ramtron.com/products/nonvola ... aspx?id=51

I'm also looking for a programmer that doesn't cost $200. If there is another chip solution, I would try it otherwise I'll probably just skip the 65C816S project.

I'm guessing that the Atmel AT28C64B 8KB EEPROM will work with it but I wanted something larger.

I basically need an economical solution.

The 1220 is a SRAM with a lithium battery in the same package and a non-volatile controller IC to monitor the power supply voltage and prevent writes to the SRAM when the voltage is out of tolerance. The 1210 is the controller IC.


DS stands for "Dallas Semiconductor," which was acquired by Maxim.

It sounds like you want to put your OS in non-volatile SRAM. That would work (as long as software bugs can't overwrite part of your OS), but that's not the normal usage for non-volatile SRAM, which is why programmers don't normally program NV SRAM. For that application, you might as well use the cheaper (E)EPROM. Trying to put the OS (or equivalent start-up code) in the same memory as your scratchpad RAM is just asking for trouble, unless the computer loads the OS from some kind of ROM every time it boots up.

http://members.multimania.co.uk/leeedav ... index.html

Lee's I2C circuit. Drivers adaptable to the 65C22 output gig for full master slave gigging?

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"My biggest dream in life? Building black plywood Habitrails"