This is accurate and great detail. I believe it is simpler than you might think. This is just a parallel interface (times two).
The work is done with the shifters and the data is pumped via a parallel interface from the processor as in the original design. I am just a software guy, but once I saw the trusty parallel chip, I figured it was a parallel interface. So how does one drive a parallel interface from Arduino/Raspberry? Probably via a serial to parallel converter board with a variant of IEEE 1284 output. I have not looked into this yet, but that's where I plan to start. Am I way off base? On Wednesday, June 5, 2019 at 4:47:46 AM UTC-4, andybiker wrote: > > Hi John, > The scans you posted answer all of the questions. > There is no "display controller" as you'd expect from the modern "fruit > machine" displays. > All we have on the board is latches and level shifters. > pins 16,18,19 control a shift register (TL5812) to select the digit > position to display (both displays selected at the same time) > there are then 4 latches - 2 for segments on top display, 2 for segments > on bottom display > These latch the 8 bit data bus (pins 4 to 11) to each level shifter. > the first 3 latches are internal to an 8255 (antique i/o port that I last > used in the early 80s) - selected with /A7 (pin3) low , /SEL4 (pin 13) low > and /WR (pin1) low /RD (pin 2) HIGH > A0 and A1 (pins 14 + 15) select which one of the 3 latches to use (and > initialise the 8255) > As this part only has 3 latches and we need 4, an extra latch has been > bolted on in the form of IC2 (74ls273) > This is selected with /SEL4 (pin 13) low, /A7 (pin 3) HIGH, /WR (pin1) low > (I think reset should be kept high - need to check data sheets) > Supplies are 47v, 5v, 4.5vAC for the filament. > > Data sheets are available for all of these chips. > I suspect that driving one is "a full time job" for something like a > simple arduino. > > I hope my ramblings help someone, > Cheers, > Andrew > > > On Tuesday, June 4, 2019 at 9:52:24 AM UTC+1, Nixcited delighted wrote: >> >> I now have my displays and the schematic. >> >> I have scanned relevant manual pages, power supply, interconnect, display >> board and component identification. >> >> https://www.dropbox.com/s/bltgd4w4o9gonuy/Alvin_G_Display.zip?dl=0 >> >> John S >> > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/aa8b0a38-a363-4b8f-ab03-237488721723%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
