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Thenk you, much appreciated. My prototype PLCC based CPU Card is currently being manufactured, so expect a follow-up video eventually. 🤓

Thanks for the advice. I'll look into it further. In reality, the extractor is probably just pulling the fumes from going straight up my nose, but then just depositing the fumes elsewhere in the room. I imagine this still beats no extractor at all. But a proper filtration system would be healthier!

Yes, I believe I might have seen that also. Perhaps it’s good to know there are potential “alternative solutions” for repairing old systems, once genuine TMS chips fall into short supply. But, from a (purely nostalgic?) Retro perspective, I always prefer the real original silicon, over a modern emulation. Especially, when it's software based emulation (as opposed to an FPGA based functional hardware re-creation). Hopefully, recovered original TMS9918 family chips will continue to be available for many years yet. 🤔🤓

@@DigicoolThings I asked the designer if he planned on putting an 80 column test mode and possibly more graphics mode on the PICO project. He said he may in the future, but for now he was just taking 'Baby' steps.

Yes, I've been through a large number of recovered EPROM chips from AliExpress. I find that many are re-marked incorrectly (both speed and manufacturer). I've also found that about 20% fail rate is expected, so you always need to buy more than you need for your old retro system repairs etc. I've been caught out a couple of times when I actually needed the access speed I ordered, only to receive much slower chips, that had been incorrectly re-marked. My experience with eBay is similar, but it just seems to be what we have to live with, in the hunt for replacement "out of production" chips.

I hadn’t looked for WDC chips on AliExpress, mainly as I prefer to buy my “still in production” chips brand new, from the likes of Mouser. I quite like the W65C816S, which apart from being in emulated 6502 mode on reset, is also a cycle accurate equivalent of the MOS 6502 (unlike the WDC W65C02S). Its native 16-bit enhancements are also of interest to someone like me, coming from a 6809 background. But I have heard it is a little more timing finicky for hardware design. Still, I have one (from Mouser), that I mean to play with! 🤓

Indeed. I started playing with a TMS9929A not long after they were available, in the early 80's. They were my first introduction to Sprites. Be sure to watch my video “TMS9929A VDP Rediscovery and Alternative Retro VRAM Solution”, which is the precursor to my MECB VDP Card design. 🤓

An interesting thought. As my hardware background was with the Motorola family, I hadn’t come across the Z80 based HD64180R before. I’ve now just read through most of the data sheet, and It’s certainly very interesting. It’s certainly a “peripheral enhanced” microprocessor, rather than an old school microcontroller. I suppose putting one on an MECB Card, we could have a jumper for whether the Bus clock was driven by “E” or the system clock, allowing support for 68xx/65xx “E” clock based peripheral cards. It could possibly make an easier entry into playing with some Z80 code, for 68xx/65xx fans. 🤔

Hi Brian. That’s actually a great idea. I could potentially achieve this with some re-work of the existing 6809 CPU Card, but it would require going to a 4 layer PCB (which has cost impact). I was originally thinking of designing a seperate PLCC specific Card, from scratch (staying with 2 layer), with the IC’s relocated to best use the space, and integrate some bank switched ROM expansion. Hmm… To go 4 layer, or not? To do a combined Card or seperate Cards? I'll see where these thoughts take me. 🤔🤓

@@DigicoolThings Perhaps if the PLCC-44 is not layed as centrally as it was on your adapter card (where it probably was the right call) then there'd be less routing agony. Maybe 0.2" to one side would suffice to disentangle the sides of the PLCC footprint from the DIL footprint? Then you're only left with two instances of DIL intersecting PLCC.

@@Brian_Of_Melbourne Yes, my initial toying around with placement lead me to the same conclusion. Centered certainly makes sense for a compact DIP40 Adapter, but on a bigger PCB disentanglement of both side pins certainly makes sense. At the moment I'm just playing around with placement and routing considerations, to help decide whether to try and go for an all-in-one combo Card, or whether to go for a second seperate PLCC Card design. Either way, it'll be a major re-route of the board with placement changes. But, it's all part of the artistic fun of PCB design. I always find a good session of PCB routing makes a great "getting in the zone" alternative to the coding "zone". 🤓

Yes. I find PLCC very appealing. The way they snap into their sockets is very satisfying! And that Through-Hole is supported, makes a nice alternative (but still retro), compared to DIL sockets. Especially at >=40 pins.

Yes, I'm going to try for a little faster and see how stable they run. I expect the main limitiation at the moment is the 150ns 28C256. The RAM is plenty fast, but I may need to try with the 70ns SST39SF040 ROM that I have on my ROM Expansion board (and potentially on a future combined PLCC Card).

Yes, all 5 worked a treat. Yet to test the 68008's. All just tested at a alightly overclocked 4MHz, at this stage.

@@DigicoolThings I sent somebody some Z84C0020VEC PLCC44 Z80s and they said they'd clocked them at 40MHz ...and they worked fine, didn't even heat up. I think they used UM61256 or UM61512 15ns SRAMs. So it would be interesting to see how the (HD63C09) do when overclocked ?

@@lezanderson1236 Yes. I've been coming to the conclusion that either the earlier CPU's were more "speed restricted" by the available memory speeds of the day, or, that the manufacturing process over their production life simply enhanced their speed capability, beyond the original datasheet specifications. Either way, it does seem that the memory speed used, is now more the primary clock speed limiting factor for our 8-bit microprocessors. Who knows? 🤔🤓

Appreciate the comment. Thank you.

Hi. I added the gerbers to the MECB_6809_CPU folder on the MECB github. But just realised from your comment, that I hadn't pushed that commit (now done!). I didn't think they were worthy of a Tindie store listing, unless someone shows interest. Perhaps a kit including the PLCC Socket and round-pin headers may be helpful / of interest to some?

Triggered by your comment, I subsequently decided I'd make the Adapter available on my Tindie store. Thinking that it may be helpful to some folk. I've made it available as PCB only, with an optional pack to make a complete Kitset, and also the option of adding a tested & verified PLCC HD63C09 (now that I've purchased some stock!). So, a one-stop for everything you need for breadboarding a PLCC 63C09, or retro-fitting a DIP40 socketed 6809 system. Currently just waiting on Tindie Admin approval.

Nice! Always wanted me a PET. Make sure you look after that baby, and preserve it for future generations!

@@DigicoolThingsMy PET is a one owner computer 🙂 Had it since new.

@@TheEmbeddedHobbyist Wow! That makes it extra special, and full of nostalgia I bet. I still have my original C64, and many of my home builds. But wish I’d managed to keep other early pre-built computers that I bought, but the reality back then was I had to sell in order to fund upgrades (like the C64).

It took a while, but then again it hasn't been my focus. I just make videos to share and document. Someone showing interest, is just a bonus. 🤓

I used an older Controleo2 Reflow Controller, that was free / surplus from an upgrade. The Controleo2 works well with just the 1 element connection. Note that I discovered the newer Controleo3 seems to require a minimum of 2 elements for it to work (so it's no good for this application). Maybe you can also find an old Contoleo2 cheap of free, from someone who is upgrading their oven to a newer Controleo version?

@@DigicoolThings Hi. Just an update. I got in touch with the company that makes/sells the Controleo3 controller to see if they had any of the Controleo2's left in stock. He thought in theory, the 3 should work with a single element but he is going to test it out and get back to me.

@@dpbarry Thanks. That would be interesting to hear the outcome. It was a long time ago now, but I'm sure at the time I couldn't get Controleo3 to work with the single element connected. However, I never followed up with them, as the Contoleo2 that I had worked fine. So, it will be good to get a definitive answer on this! 🧐

@@DigicoolThings No Problem. I'll keep you informed

Yes, that had occurred to me, although the NOP is of course incrementing the Program Counter register. Being a dynamic part it would be fair to assume that any register, including the PC register, would be affected in the same way. 🤔

Thanks for your support. It is much appreciated! Now I have to get on with sorting out some 6502 code, so I can get the new CPU card doing a bit more than just the initial test. 🤓

@@DigicoolThings in time, there's going to be a healthy ecosystem around this - I might leave the hardware up to you guys who know what you're doing & I might work on that software library and maybe some documentation and some turn-key solutions when I get grounded in my own fundamentals...

2024: I assume that you just completely missed that I obtained my replacement LTH7 from AliExpress (i.e. Chinese), and that I clearly demonstrated this replacement resolved the problem. Also, I have had many people thank me for helping them to resolve this problem for themselves. You are of course welcome to your opinion.

Video design took my interest from the start, when I was initially playing with early “pong” video game circuits as part of my initial exposure to digital electronics design, as a teenager. So it’s good fun to again play with the early video display chips.

@@DigicoolThings My problem was I liked playing with electronics as a 14 year old, left school at 16 with no idea what I was going to do. 😞 two weeks later I was working for an avionics company. who would have guessed. I would never have thought at the time I would be an electronics engineer for the next 54 years.

@@TheEmbeddedHobbyist They were interesting times. I left school at 17. Having made and programmed my own microprocessor systems I tried to get a job in Computers, but was told I would get bored at lower jobs, but didn’t have the qualifications for jobs that matched my capabilities. Joined a retail electronics distribution company instead, and ended up computerising that business, and designing microcontroller devices as a side. I think what you end up as, is whatever you make of wherever you are. 🤔

@@DigicoolThings well I now tell youngsters if you really love your hobby don't get a job in that area. Your love your day job but will but lose your hobby. I found that its hard to come home and do the same thing again in your free time. But that's what I found.

@@TheEmbeddedHobbyist I do understand. My work life took over everything, but it was also very rewarding. Unfortunately, too many people get stuck in jobs they don’t really enjoy. I always tell people they should just follow their passion. That's usually the path to happiness and success.

Totally agree that one SD video standard would have been much more sensible, and the world would be a better place. But then again, there are so many competing standards that have got in the way of focusing on just deliver single worldwide standard solutions. I mean, we could start with 50Hz vs 60Hz mains power, 240V vs 120V, or even just a single worldwide Mains Power Plug standard would lower manufacturing costs. Then we have Imperial vs the vastly simpler Metric system. We humans just like making harder work for ourselves! 🤔

@@DigicoolThings imperial was much easer in the old days when we had 12 fingers and toes. A genetic nutation forced us in to the metric system. that's when they stopped us marrying our sisters cos octal is much harder. 🙂

@@TheEmbeddedHobbyist Unfortunately, all I can say about that is in my country we switched from Imperial when I was at young / junior school. All I remember is that everything became so much easier overnight, when everything suddenly was a power of ten conversion! Of course, I also understand that those who have grown-up with Imperial for their whole life will naturally find it easier than re-learning in terms of powers of 10. 🤔

@@DigicoolThings i remember 12 pennies to a shilling, 20 shillings to a pound, 21 to a guinea. As a kid you could get quite a lot of sweets for a thruppenny bit. 🙂

Thank you for your kind comment. I have lots of plans, but limits on my available time. However, we are steadily progressing. 🤓

Yes, although that didn't put me off, as the functionality was my main priority. I'm using the DC connector for powering my VersaTerm. For all of my current 5V powered projects I've actually gone to the USB-C connector, as I find it a nice 5V solution that also avoids the reverse polarity / over voltage risk of using the age-old DC connector Power adapters. Plus, thanks to the RaspberryPi, USB-C plug terminated 5V DC Power Adapters are relatively cheap. 🤓

@@DigicoolThings I use those USB to magnetic corrector things.That way one cable does multiple devices regardless of original connector..

@@aprusek Good idea. I must look into further. Thanks.

@@DigicoolThings A while back I built "Geoff's VT100" which is a PIC based vt100, and way back wrote a Hazeltine 1500 emulator to tun on a Model II Tandy.

@@aprusek Yes, I came across Geoff's VT100 variations, while searching for a good stand-alone terminal. The recent VersaTerm won me over with it's USB keyboard and HDMI output options allowing use with more modern keyboards and displays (plus, I had an unused Pico in my parts drawer). p.s. I ended up ordering some small USB-C to mini-USB and micro-USB adapter plugs to satisfy connecting my USB-C 5V power source to the different USB power connectors. I didn't find a magnetic solution for mini-USB, only micro and USB-C.

LOL. Yes, I do understand your thinking. But, unfortunately, I'm a bit of a perfectionist, so I've also been known to roll a new minor version for something as trivial as some PCB routing I'm not 100% happy with. Possibly why PCB design always takes me longer than most, and I never submit a PCB order on the same day as I finish routing that PCB. I mean, I always need to sleep on it, in case there's one last change I missed. 🤔🤓

@@DigicoolThings I used to have to go over the Gerbers track by track and using a highlighter mark the track off in the circuit diagram. then check, checking widths and number of via's etc don't miss that a bit 🙂

@@TheEmbeddedHobbyist Yep, I sure remember the days of playing with rolls of routing tape, DIL transfers, and transparent film. Perhaps that's why we enjoy creating PCBs these days, given how enjoyable it now is, compared to the highly fiddly, manual, and labour intensive experience we once put ourselves through! 🙂

Thanks. It’s been a slow start for me in 2024, as life was just getting in the way. But I can now feel the momentum rising! 🤓

Thanks for your comment. You can find the verified “original” ASSIST09 source, made compliant with ASM6809, on my MECB GitHub as ASSIST09_Original_ASM6809.asm. Good to know it might be helpful to others. 🤓

Thanks. It was quick, but hopefully it was helpful for you. 🤓

@@DigicoolThings It really was :)

Thanks for your comment. I've just answered your question on the Forum. Welcome to the Forum by the way! :)

@@DigicoolThings Thanks for your quick response and I’ve just replied on the forum. 👍

Thanks for your kind comment. I’d be interested in hearing more about your project, and how you implement your MMU. The original ECB (and potentially therefore MECB), has 24 Address lines available (16MB), so I could potentially also create a larger RAM / ROM memory card to extend to 2MB or even beyond to 16MB. NitrOS-9 on a 63C09, with plenty of memory, would be a nice to have running!

Thanks for your comment. It's great to know it was helpful to someone. 🤓

It'll be interesting to hear how your chips go. I'm was guessing that it's more likely that wrongly re-marked chips are the 'E' chips marked as HD63C09P, simply because the people re-marking them perhaps don't know the difference? Unless, they they're intentionally re-marking Internal clock chips incorrectly as 'E' varients, as they're in higher demand, so easier to sell? It's a mystery! 🤔

Fair call. I guess calling anything Retro that's based on an RP2040, seems to be stretching things a bit. But, I'd say that it's the intended function that is indeed Retro. 🤓

Thank you for the compliment. David noted the terminal was limited to 80 chars because of Pico performance limitations. It runs at 640x480 standard VGA resolution, hence 8 pixel width font with 80 chars per line. The PicoVGA code he is using presumably can't handle the timing for higher pixel rates, to give a higher display resolution required for 132 columns.

You can create user uploadable fonts. Also, all of the source code is published on the github repository, so you are able to modify it (e.g. alter the native fonts included, or implement custom features), and recompile. Note however that the fonts are all based on a 8-bit character cell width (640 pixel VGA screen, for 80 chars x 8-bits).

The device in the top-right is a GBS-8200 RGB to VGA convertor, that has been modified with the GBS-Control upgrade to make a really awesome (and low priced) VGA convertor, for retro gear and projects. I've since mounted it in a nice 3D printed case, but it's still in regular use! I do highly recommend this as a project if you're planning on running a TMS-RGB based output on a VGA monitor. 🤓

Good idea, I'll give that a try. It didn't really occur to me to try this, as I just assumed these were probably all re-marked original 6502 chips (I haven't attacked them with Acetone yet either, to look for original markings). 🤔

@@DigicoolThings they most likely are dodgy... But they could be one of the rp65c02 types.

@@DavidLatham-productiondave Yes. I've just now tried them with the jumpers in 65C02 settings, and still non-functional. Was defiinately worth trying though! Thanks for the suggestion. Next step will be some Acetone, so I can see if I can reveal the original part numbers. I suspect they're just faulty chips, given they'll all be recovered from old equipment, and no doubt subjected to lots of static and heat in the process. 😮

Thanks. I guess the best placing of the connectors depends on your own situation. For me, I just wished the power connector was also on the "back" with the monitor and keyboard connections. So just the serial connections, that I'll be regularly connecting to, where on the front. But, I imagine David's PCB layout was also related to making the unit as compact as he could, especially given that connector location preferences are quite subjective. If you build one too, I hope it proves as useful as mine has. 🤓

Yes, the HDMI connector is challenging. I solder under a magnifier (trinocular microscope), and use a Axun T210 handled station. I like the small bent-end tips for most work, as it seems best for getting good contact / heat transfer when using a small tip. By setting the screen mode to Monochrome, and setting the ANSI colour for "Monochrome text" you can set colours other than white, for background / normal / bold. I'm currently using a nice Amber by setting the "Monochrome normal text" colour to F0.

Thanks for the feedback. Glad you found it enjoyable. 🤓

Thanks. Wow, your dad is lucky. A genuine Televideo 920c would be very nice to have, and getting hard to find these days. I guess, unless he is also wanting something a little more portable, he probably won't have a use for a VersaTerm with a genuine Televideo terminal on his desk!

Excellent question! Basically, one of the attractions of the VersaTerm is that it supports either PS/2 or USB keyboards. Finding a moderm, compact, mechanical keyboard, that also supports PS/2 conection mode, is getting difficult. I was wanting a "space saving" compact Mechanical keyboard, and found the reasonably priced good quality "Royal Kludge" RK84 from AliExpress. However, it only provides wireless or USB connectivity (no PS/2 mode, so a simple PS/2 adapter won't work).

Thanks. I’ll definitely take that as another vote to keep filming some assembly. Also great to hear from another Kiwi. Hopefully, you’re now a bit more inspired to progress your projects! I know, like many, I have too many projects on hold. 🤓

Yes. I just ordered a 10" Eyoyo IPS HDMI/VGA/Video 1920x1200 monitor from AliExpress for around $100. I was after a small monitor, and this seemed the best for resolution, inputs, and display quality. Not too bad a price, but you can get a good much larger monitor for the same price. So, small / portable seems to command a premium.

You might look at refurbs. It's been a few years since I bought some.