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Forum Index : Microcontroller and PC projects : CMM interfacing with 5V CMOS
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thwill Guru  Joined: 16/09/2019 Location: United KingdomPosts: 3848 |
Hi Bill, You are undoubtedly correct, but I already have the 4000 silicon and it's ultimately more about the journey than the destination. Doing it the hard way (epoxy blobs permitting) is likely to teach me more than doing it the "easy" way. No doubt I will have more questions in the future and you can remind me that you recommended 74hc. None of this is going to happen quickly anyway, I'm locked down with a wife and two very young children, it doesn't make for much hobby time. Best wishes, Tom Game*Mite, CMM2 Welcome Tape, Creaky old text adventures |
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| PeterB Guru Joined: 05/02/2015 Location: AustraliaPosts: 639 |
Got the "B" I understand how the code works. The OR functions set up the bits in out and the AND functions mask them prior to printing. So simple so why did it take me so long? The problem is, it still doesn't work.  Peter |
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Turbo46 Guru Joined: 24/12/2017 Location: AustraliaPosts: 1593 |
Please explain? Do you mean that you are just getting the "B" bit of the data? Bill Keep safe. Live long and prosper. |
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| PeterB Guru Joined: 05/02/2015 Location: AustraliaPosts: 639 |
Back when I worked for a living I would get a bit excited when I found a problem that I had been chasing for some time. A loud "got the B.........." announced my victory. After I have finished the roast etc I will get stuck into the hardware. Or have a sleep  Peter |
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| PeterB Guru Joined: 05/02/2015 Location: AustraliaPosts: 639 |
Would you believe it? In the final PRINT "Right" the first " had been corrupted to ' and with my old eyes and the font used it didn't stand out. So now I know how it works and it does work. And the reason I'm so late is I did have a sleep and the kids called to see if I'm still vertical. And now I am tickled pink and I might open the last cab sav that I have been saving until HER rooms has been cleaned out. A happy Peter     |
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| Turbo46 Guru Joined: 24/12/2017 Location: AustraliaPosts: 1593 |
Got the other "B"  Bill Keep safe. Live long and prosper. |
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| thwill Guru Joined: 16/09/2019 Location: United KingdomPosts: 3848 |
Hurrah, well done! Just to confirm this is with the MM outputs (LATCH & CLOCK) configured as open collectors (OOUT) and pulling 5V through 10K resistors? I expect to confirm the same myself this weekend, if only on a solderless breadboard. Then I can get onto the serious business of cursing the epoxy blob on this Famiclone. ... of course maybe the ~2m cable between MM and 4021/controller is the issue? I guess there are ways I could bypass that ... but I'm not sure I can be bothered. Thanks for all your efforts, Tom Game*Mite, CMM2 Welcome Tape, Creaky old text adventures |
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| PeterB Guru Joined: 05/02/2015 Location: AustraliaPosts: 639 |
Yep. It uses oout and all R's are 10k and there is a 0.1uF on the chip. My cable would be 200mm. It really did have me going. At 1:30 this morning I was sitting up in bed trying to understand your code. It fell into place as I was cooking lunch. The nice thing is, I can still cope with fairly simple problems it just takes longer.  Peter p.s. The cab sab is delicious. P Edited 2020-04-18 18:18 by PeterB |
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| thwill Guru Joined: 16/09/2019 Location: United KingdomPosts: 3848 |
Latest update: Well it didn't take long to knock up an "NES controller" on solderless breadboard and it worked first time! Using 4k7 pull-ups throughout: - It works with open collector and 5V Vcc, CLOCK and LATCH - It works with open collector 3.3V Vcc, CLOCK and LATCH - It works with normal digital output 3.3V Vcc, CLOCK and LATCH I just hope I didn't fritz anything on my MM when I briefly had a 5V DATA line connected to a non-5V tolerant pin ... seems to be OK. Glamour shot for posterity:  (Note that in the above the DB9 isn't connected, but its breakout board is connecting the lines across the central divide.) As a sanity check I then attached the Famiclone controller and as previously reported it requires 1k pull-ups on CLOCK and LATCH to work. I guess the only thing left would be to attach flying leads from the inside of the Famiclone controller to my breadboard "NES controller" and eliminate the lead as the problem ... I'm not sure I can be bothered going to the trouble. Best wishes, Tom Game*Mite, CMM2 Welcome Tape, Creaky old text adventures |
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| Turbo46 Guru Joined: 24/12/2017 Location: AustraliaPosts: 1593 |
Congratulations Tom, That's very neat! Are you going to add in the 'turbo' oscillator? your 555 may be be handy for that (at 5 volts) - a bit more compact than using the NAND gate. See this circuit. How would you feel it it was the cable after all this? You could perhaps just tack onto the power, clock and latch leads for your circuit and only lift off the data lead. Remember Murphy's law!. Bill Keep safe. Live long and prosper. |
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| thwill Guru Joined: 16/09/2019 Location: United KingdomPosts: 3848 |
Thank you, I'm pleased. I don't need/want the autofire buttons for my project, but I might have a play for education's sake; thanks for the link. Because as it turns out IT IS THE CABLE. I completely unsoldered the cable from the Famiclone controller and used it instead of the fly leads to connect the breadboard NES controller to the MM breadboard. The end result is a very similar error to that originally observed. With a 4k7 pull-up on the LATCH button A reads, and all other buttons read as RIGHT (bit 7) instead of not reading at all. Change to a 1k pull-up and it works fine. It then occurred to me that my homemade DB-9 breakout board might be at fault, so I wired a female DB-9 connector to the breadboard NES controller with 4 cm fly leads and plugged it into the MM breadboard via the DB-9 breakout board. i.e. I replaced the cable with short fly leads but kept everything else the same. It worked just fine. I think that means I've narrowed the cause of the problem down to the 5-core cable (or its molded female DB-9), not something I have a spare of. Does that give anyone a eureka moment as to why it works with normal digital input and not with an open collector? Ultimately I put the Famiclone controller back together and tested it again and it still doesn't work with an open-collector CLOCK ... I had worried for a moment at about midday whether the whole problem might be down to 20 year old solder joints in the Famiclone controller and I had been wasting everybody's time with this little mystery, but it turns out not - phew! Regards, Tom Edited 2020-04-19 08:57 by thwill Game*Mite, CMM2 Welcome Tape, Creaky old text adventures |
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| Turbo46 Guru Joined: 24/12/2017 Location: AustraliaPosts: 1593 |
Sorry, no eureka moment but it could be just a dicky crimp joint in the connector. Not crimped properly, a bit of corrosion and needing a bit of extra whetting current through the joint to break through. Or it could be damage due to mistreatment over the years. I know some people who cannot grasp the concept of pulling out a plug by the plug and not the cable no matter how many phone cables they break. Is the next step to cut off the connector and connect the cable to the breadboard? Bill Keep safe. Live long and prosper. |
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| PeterB Guru Joined: 05/02/2015 Location: AustraliaPosts: 639 |
Good morning Tom. I think you have learnt one very useful lesson, these chips are robust. The odd zap to 5 Volts doesn't seem to worry them. Even reverse polarity doesn't destroy them. You have not been wasting our time,it has been fun and we Australians often spend time together under the bed .One other very important tip. try not to be so neat. Peter |
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| thwill Guru Joined: 16/09/2019 Location: United KingdomPosts: 3848 |
Hi Bill, Sounds plausible. Not impossible, but it was supposed to be new old stock. I guess it could have been repackaged. I suppose I could do that, but presumably the end of that path leads to dissection of the moulded plug ... to what end other than to satisfy curiosity? This controller came with my (unbuilt) Gigatron TTL computer kit and I'd rather not destroy it since replacement controllers can't be bought cheaply on eBay. I think what I will do instead is wait until after CV-19 and then snag some multi-core cable from my father in law to test that my breadboard controller still works at the end of a long lead (unless I dismantle it in the meantime). For now I'm going to switch my attention andd try and beat a MAX7219 LED driver into submission. The code I snagged from another thread doesn't seem to work out of the box. Or more likely I've stuffed up something on the hardware end. Best wishes, Tom Game*Mite, CMM2 Welcome Tape, Creaky old text adventures |
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| thwill Guru Joined: 16/09/2019 Location: United KingdomPosts: 3848 |
That's fortunate ;-) I agree it has been fun. Personally I thought it could do with nicely cut jumpers rather than all those looped breadboard connectors  Best wishes, Tom Game*Mite, CMM2 Welcome Tape, Creaky old text adventures |
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| Turbo46 Guru Joined: 24/12/2017 Location: AustraliaPosts: 1593 |
I would have to know for sure. If the connector has faulty connections then it will always be faulty. Same deal for the cable. You can replace the connector and/or the cable if you need to. You can even buy a cable with moulded connectors if you want to. The controller would be of no use to me if it was suspect. By the way, as Crocodile Dundee would say "That's not a LED matrix, this is a LED matrix. Bill Keep safe. Live long and prosper. |
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| Turbo46 Guru Joined: 24/12/2017 Location: AustraliaPosts: 1593 |
Bollocks, the 1K resistor current doesn't go through the connector.  Maybe the 1K resistor causes a faster rise time and that causes a greater spike of current through the connector to charge the cable capacitance and that of the blob's imput - or just maybe I haven't a bloody clue. Bill Keep safe. Live long and prosper. |
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| thwill Guru Joined: 16/09/2019 Location: United KingdomPosts: 3848 |
Hi Bill, Since this clearly vexes you so badly I have ordered a replacement cable (on the slow boat from China). Assuming that works it would be my pleasure to send you the original so you can dismantle it and/or take it out into your backyard and smash it to smithereens with a sledgehammer I would be impressed if they had built it by hand from 2048 discrete LEDs. Otherwise all they've proved is the ability to use eBay. That said I started last night working on a Game of Life implementation on 4 off-the-shelf 8x8 matrices driven by MAX7219's. Best wishes, Tom Game*Mite, CMM2 Welcome Tape, Creaky old text adventures |
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| thwill Guru Joined: 16/09/2019 Location: United KingdomPosts: 3848 |
This reminds me of the following joke, which I no doubt tell poorly: Three students wake up separately in their rooms to find that their paper bin is on fire. The engineering student grabs the fire extinguisher and sprays it liberally and with great glee everywhere to extinguish the fire. They go back to bed satisfied that the problem is solved. The physics student grabs the fire extinguisher, calculates exactly the position that the nozzle should be directed and the amount of water that should be used and carefully puts out the fire with the minimum of collateral damage. They go back to bed satisfied that the problem is solved. The maths student notices that there is a fire extinguisher and goes back to bed satisfied that a solution to the problem exists! Best wishes, Tom Edited 2020-04-24 00:22 by thwill Game*Mite, CMM2 Welcome Tape, Creaky old text adventures |
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| Turbo46 Guru Joined: 24/12/2017 Location: AustraliaPosts: 1593 |
Hah! the technical student would have put out the fire, examined the paper bin, found that it was made of a mesh material and replaced it with an enclosed peddle bin with a tight fitting lid so the problem would not re-occur. Conway's Game of Life has always fascinated me and that display inspired me to write one for MMBasic DOS. It generates a random matrix and still fascinates me the way it can go through many generations and eventually reach a stable state. I thought of using it for the basis of a Maximite game in which you could design (and save) the seeding matrix. Bill PS. MMEdit and MMBasic DOS can be brilliant for quick development if I/O is not needed. Keep safe. Live long and prosper. |
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