Actually, the 8255 and an LS273, both through HV buffers, drive the segments.Ports A and B of the 8255 drive the "upper" VFD anodes (+47V) while Port C and the LS273 drive the "lower" VFD anodes (+47V). The TL5812 drives the digit grids (one per digit) through a separate serial shift register interface.
It's a classic configuration for a multiplexed display, that can be easily controlled by any modern microcontroller with 16 free pins without recurring to specialized hardware. Just plain old parallel interface for the segments plus a little bit-banging for the digits. If one wants to use a processor with less free pins, it can be done too, but the complexity grows. I just ordered a couple of this boards and am crossing my fingers... On Wednesday, September 18, 2019 at 1:00:41 PM UTC-3, Keith Moore wrote: > > Richard, I have not yet done it, but I do plan to at some time. I got a > few of these for various reasons (demo/display, etc.). I assume you have > the detailed data / pinball instruction sheet like I do. If not, let me > know. > > https://www.dropbox.com/s/bltgd4w4o9gonuy/Alvin_G_Display.zip?dl=0 > > > My chops aren't good enough to just whip out the electronics to drive > these, but I was planning on making a computer that does this eventually. > It is an IEEE 8255 interface. I should be able to do it with an arduino. > > > On Tuesday, September 17, 2019 at 11:11:26 PM UTC-4, Richard Scales wrote: >> >> I was wondering whether anyone has had any success talking to the Alvin G >> PCA-003 boards that are available: >> https://www.pinballspareparts.com.au/electronics/displays/pca-003.html >> <https://www.pinballspareparts.com.au/electronics/displays/pca-003.html?fbclid=IwAR2epmNiBA7UkcB1H0XqUivyeQEMSmN1HWyIhaM-oZXsEYUmPsewaJ0FLSw> >> I would be interested to hear from anyone that has managed to talk to one >> or who might be able to provide any insight into how their interface works. >> I have a few coming my way and would like to see if I can make them talk >> somehow. >> Any pointers to information about interfacing requirements and protocols >> etc would be most welcome. >> >> -- 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 view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/7b3c9600-fda0-4370-9194-7ddc71a09799%40googlegroups.com.
