R65F11A FORTH Chips for Sale

[glitch]

Not my listing, and they're coming from China so who knows, but:

https://www.ebay.com/itm/185625244395

I've ordered three for myself, I'll test them in one of my projects once they come in, if folks want to wait on that before they pay. Usually I won't buy ICs from China, but these never come up!

[jds]

I bought two of these from e-bay a while ago (from a different seller). I've have liked to have gotten a 65F12, but have never seen them for sale. Mine have exactly the same markings, including the date code which seems quite co-incidental, bu maybe they just made a large batch that week? One of mine has been running every day in a small board I built, and even has a floppy drive attached.

[glitch]

These finally arrived! I tested them in my little R65F11 project board and they work; however, I ordered three and the seller only shipped two. I've contacted them to see if I can get the third shipped to me, as these are nice quality chips that haven't been "refurbished" (blacktopped or walnut blasted, and new marking engraved). Here's a picture of them, as received:

[glitch]

Seller is going to ship the one they forgot, so I feel pretty OK recommending this one if folks want to grab a FORTH chip.

[Martin_H]

glitch wrote:

Seller is going to ship the one they forgot, so I feel pretty OK recommending this one if folks want to grab a FORTH chip.

Is there a PCB to plug these into? Or are you planning on making one?

[jds]

Martin_H wrote:

glitch wrote:

Seller is going to ship the one they forgot, so I feel pretty OK recommending this one if folks want to grab a FORTH chip.

Is there a PCB to plug these into? Or are you planning on making one?

I have built a board around this chip, I posted some information at viewtopic.php?f=4&t=6537

I have also built a Rockwell Forth compatible floppy controller. viewtopic.php?f=4&t=7091

I'd be happy to share the schematics, and PCB designs, but so far I haven't uploaded them anywhere.

[Martin_H]

Really neat. It would be interesting to see what projects you use this computer for.

[jds]

It does get quite a bit of usage, I've got a small backplane and a 3.5 inch floppy drive hooked up to it. The drive is 1.44MB, but the controller only supports 720kb, which is more than enough anyway. I can store Forth screens on disk, so can save my work. Thinking about it, mostly I'm using it to learn Forth. I've been trying to set up some sort of floppy data transfer so I could assemble code on a larger computer and then load it via floppy. This is quite challenging because the Forth floppy format is quite different to anything my computer can write. The sector size is 256 bytes, but interestingly the built in routines will quite happily read a 512 byte sector. So I can write a sector under linux and read it on the Forth system. I'm building up some Forth words to read from the disk and program the Flash chip. I should really try connecting up two floppy drives so I can have one for reading and writing Forth screens and the other for data. There's a second floppy drive connector on the disk controller that uses a FPC connector to connect to a Teac FD-05 laptop style drive. I haven't tried that yet so I don't know if it even works.

I didn't have a lot of luck with serial software download, it's something to do with flow control I guess, but I didn't persist in getting to the bottom of it as I had the floppy drive.

It has worked reliably, which I am pleased about. The CPU board is also the only board that I've made that didn't require any corrections. The floppy controller did require a bit of debugging and has some patch wires.

I did think that this wasn't of a lot of interest to others because the R65F11 and R65F12 were quite rare, so it would be hard to get one, but it looks like there might be a few more available. It'd be interesting to know how many this ebay supplier has. I see they are starting to see a few now, currently 17 sold. There's probably a good enough supply for people to use them to build a development system, but there's also the option of using a R6501Q based Forth system, and there's a lot more R6501Q's around.

[jds]

I ordered two of these chips as well. They just arrived so I put one in my board to see if it worked and its all working perfectly, so these are indeed genuine.

It's good to see some available, when I got my first two it appeared that they were very hard to find. Around the same time I found a development ROM which is a useful thing to have as well, since I don't have an EPROM programmer. It makes quite a good development system. It only has a 16k address range, but the Forth has a bank switching scheme included, so I used this to address more RAM and also to have read and write access to a 128k Flash ROM chip for programming.

[glitch]

Martin_H wrote:

glitch wrote:

Seller is going to ship the one they forgot, so I feel pretty OK recommending this one if folks want to grab a FORTH chip.

Is there a PCB to plug these into? Or are you planning on making one?

I'm working on a wire wrap project using the first one I'd gotten from a friend, a clock project using a fancy ASCII display. I didn't expect to find more so I haven't laid out a board for it! Don't know if I will or not, but the seller seems to have a bunch more, so maybe?

[glitch]

jds wrote:

Martin_H wrote:

glitch wrote:

Seller is going to ship the one they forgot, so I feel pretty OK recommending this one if folks want to grab a FORTH chip.

Is there a PCB to plug these into? Or are you planning on making one?

I have built a board around this chip, I posted some information at viewtopic.php?f=4&t=6537

I have also built a Rockwell Forth compatible floppy controller. viewtopic.php?f=4&t=7091

I'd be happy to share the schematics, and PCB designs, but so far I haven't uploaded them anywhere.

Very nice work! I ended up going with a GAL, 8K SRAM, and 16K EPROM for mine -- couldn't fork over for that original FORTH ROM I have it set up so I can change the GAL equations and adjust how much of memory is ROM and how much is RAM. It's currently split 8K RAM/8K EPROM but eventually the project will get ROMed which will require an increase in ROM space size.

[glitch]

Final follow-up, the seller did send the chip missing from the initial order, and the one received is also genuine and not remarked.