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(Topic ID: 275958)

Converting from Alpha-numeric to LCD


By sixtyfourbits

66 days ago



Topic Stats

  • 16 posts
  • 11 Pinsiders participating
  • Latest reply 59 days ago by TheNoTrashCougar
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There have been 2 images uploaded to this topic. (View topic image gallery).

display segment info (resized).png
robo (resized).jpg

#1 66 days ago

Hey everyone,
So I had a random thought, and couldn't really find anything by searching the forum.
I have a robocop pinball machine which has a display missing a display line. I most likely have to get the board repaired. Which got me thinking, is there a proven way to put a small lcd screen in instead? Has anyone here done something similar to another alpha-numeric game?
I would want to keep the rules stock, and use the original wiring harness for all the sensors, targets, etc. I would basically need to figure out a way to change the display data from the alphanumeric input to one that would connect to as well as show up on a lcd screen.
I realize it wouldn't be easy, but if someone has done this before, I'd love to read a thread on how they did it. Again, I'm not looking to reprogram any rules. Just change the display format. I'm just curious to see if anyone else has already found a way/program to bridge the display connection both physically and data input wise as well. I'm up for a challenge and learning a new program, just wanted to see if anyone has done this so that their journey can be used as a bit of a guide so that I'm not going in completely blind hahaha.

robo (resized).jpg

#2 66 days ago
Quoted from sixtyfourbits:

Hey everyone,
So I had a random thought, and couldn't really find anything by searching the forum.
I have a robocop pinball machine which has a display missing a display line. I most likely have to get the board repaired. Which got me thinking, is there a proven way to put a small lcd screen in instead? Has anyone here done something similar to another alpha-numeric game?
I would want to keep the rules stock, and use the original wiring harness for all the sensors, targets, etc. I would basically need to figure out a way to change the display data from the alphanumeric input to one that would connect to as well as show up on a lcd screen.
I realize it wouldn't be easy, but if someone has done this before, I'd love to read a thread on how they did it. Again, I'm not looking to reprogram any rules. Just change the display format. I'm just curious to see if anyone else has already found a way/program to bridge the display connection both physically and data input wise as well. I'm up for a challenge and learning a new program, just wanted to see if anyone has done this so that their journey can be used as a bit of a guide so that I'm not going in completely blind hahaha.
[quoted image]

While I've not done it, nor have I see a thread on Pinside discuss it (doesn't mean it's not here somewhere), my assumption is that you would need some sort of data converter that receives the input for the numerical display and outputs in a format the LCD would understand. Might be a Arduino project for someone with the technical savvy (beyond my skillset). Interesting idea, however.

#3 66 days ago
Quoted from Mr_Tantrum:

While I've not done it, nor have I see a thread on Pinside discuss it (doesn't mean it's not here somewhere), my assumption is that you would need some sort of data converter that receives the input for the numerical display and outputs in a format the LCD would understand. Might be a Arduino project for someone with the technical savvy (beyond my skillset). Interesting idea, however.

That was my thinking too. I'm not sure if such a data converter would have to have game specific programming or not. Regardless, if someone is able to create a converter, that would open up a fair bit of project ideas for all sorts of alpha-numeric games.

#4 66 days ago

I was thinking the same thing for a Data East Simpsons machine.

#5 66 days ago

To successfully convert between two systems (or emulate one system on another system) it is necessary to have a very good understanding of both systems. That is my experience from having written software emulators. I have never built a hardware emulator.

Alphanumeric display output is actually fair simple. Numeric displays contain 7 segments and the dot/comma (for a total of 8 elements). Alphanumeric displays contain 14 segments, the dot and comma (for a total of 16 segments). The display board consists of 16 individual displays on the top and 16 individual displays on the bottom. That correspond to 32 displays. The individual top and bottom displays are controlled simultaneously as a strobe. The configuration for the top and bottom segments is set and then strobed. The next configuration is then strobed and so on until all 16 top and bottom configurations are strobed. It then cycles back to the first strobe. It's somewhat like how the old cathode ray tubes refresh their images. The image does not flick due to the way the human eye perceives the light even though the electronics responds immediately.

To build a converter you would need to understand how this works and importantly the timing because the signal is constantly changing. It would need to store the entire image for one complete cycle (from strobe 1 to strobe 16) and then construct that image to display on the LCD.

Note that Williams changed the on and off state of the configuration from the double (7) alphanumeric + double (7) numeric display (such as Swords of Fury) to the double alphanumeric panel (such as Black Knight 2000). The Data East on/off state remained the same for all their boards.

#6 66 days ago

This is on my "someday" project list. DMD extender uses a Raspberry PI to decode the DMD signals, render the image, and output it over HDMI. I want to do the same thing, but for machines with alphanumeric displays.

#7 66 days ago
Quoted from DumbAss:

To successfully convert between two systems (or emulate one system on another system) it is necessary to have a very good understanding of both systems. That is my experience from having written software emulators. I have never built a hardware emulator.
Alphanumeric display output is actually fair simple. Numeric displays contain 7 segments and the dot/comma (for a total of 8 elements). Alphanumeric displays contain 14 segments, the dot and comma (for a total of 16 segments). The display board consists of 16 individual displays on the top and 16 individual displays on the bottom. That correspond to 32 displays. The individual top and bottom displays are controlled simultaneously as a strobe. The configuration for the top and bottom segments is set and then strobed. The next configuration is then strobed and so on until all 16 top and bottom configurations are strobed. It then cycles back to the first strobe. It's somewhat like how the old cathode ray tubes refresh their images. The image does not flick due to the way the human eye perceives the light even though the electronics responds immediately.
To build a converter you would need to understand how this works and importantly the timing because the signal is constantly changing. It would need to store the entire image for one complete cycle (from strobe 1 to strobe 16) and then construct that image to display on the LCD.
Note that Williams changed the on and off state of the configuration from the double (7) alphanumeric + double (7) numeric display (such as Swords of Fury) to the double alphanumeric panel (such as Black Knight 2000). The Data East on/off state remained the same for all their boards.

Well, after that explanation I think you need to change your Pinside name.

#8 65 days ago

The segment data is sent as the 7 segment data for all displays including alpha-numeric, and the extended segment data is sent as well on different lines on the same strobe (for the 2 alpha numeric 14 segment displays in the 4x7, or all if it's the 2x16). As dumbass noted, the 4x7 displays' data are inverted vs. Data East and the 2x16 displays, but you can flip that easily enough when you grab the data. IIRC all the strobes are present in BOTH systems, so even with a 4x7, it's still strobing 16 times. (You'd only need 14 if you were just sending 4x7 as 2 digit pairs per strobe).

The circuit that's going to grab the data would be something like this:

Connect up all the segment lines to inputs. (14 segments per character, +1 bit for the period and +1 bit for the comma extension, IIRC)
Connect up all the strobe lines to inputs.
Watch the strobe lines and when one strobes, grab the segment data. Depending on which one strobes, you know which digit it is. You need to store 32 bits of segment data per character position, top and bottom. Invert it if it's the earlier 4x7 displays.

Outputting to your LCD is something I know zip about, but you're going to just take the segment data and combine it into characters and insert it into the appropriate position on the display. Also, I don't remember which special strobe is used to handle 'extra' displays like the credit display on the very early games, or the extra display on Taxi for instance. There might be an extra set of segment data for those machines and they merely do 3 sets of segment data on certain strobes.

The strobe ends up being your trigger at any rate - if you grab the segment data after the strobe, you should be able to write a glue logic program to output to the LCD (especially if it's an LCD that lets you do position manipulation, i.e. you can tell it, put this segment data at this position and don't change anything else).
If you're short on input pins on your platform you could possibly come up with some logic to take the 16 strobes and crunch them down to 4 bits and just read/react to that.

Now, it looks like the OP wanted to modify the actual DE code instead to run the LCD panel directly - that could be done as well but you better know 6800 assembly language and be willing to disassemble quite a bit of the original code to change that one. As a bonus in that case you can change the way the segment data is output. I don't think you're going to find something plug and play though.... there's going to be either glue logic in terms of decoder chips, or software; or modification of the actual data east code. pinballcode.com has done a lot of extensive work on data east games and would be most familiar with how it's internally constructed, maybe you can get some hints from him.

Ed Cheung's williams tester from a long time ago used a small 2x20 display to show the displays, and that was way back when, so definitely doable that way, although that was probably a system7 or 9 tester - so no extended segment data to worry about there.

#9 65 days ago

Back about 5 years ago I did some home brew pinball stuff with an old Williams Flash. I wanted to keep the game looking original, so I build an Aduino Uno that hooked up to a computer via USB and ran the segments and strobes on the displays. So as previously discussed, capturing the display output from system 11 MPU board can be done. As for outputting to an LCD, I think with something a little more powerful that an Aduino could do it.

#10 65 days ago
Quoted from Mr_Tantrum:

Well, after that explanation I think you need to change your Pinside name.

You should see the boards he designed.

#11 65 days ago
Quoted from DumbAss:

That is my experience from having written software emulators. I have never built a hardware emulator.

Pretty much my opposite -- I have a lot of experience emulating hardware but not much in emulating software.

#12 65 days ago
Quoted from slochar:

Also, I don't remember which special strobe is used to handle 'extra' displays like the credit display on the very early games, or the extra display on Taxi for instance. There might be an extra set of segment data for those machines and they merely do 3 sets of segment data on certain strobes.

The status (credit/match/ball-in-play) is strobe 1 and strobe 9. Strobes 2-8 form the left of 7 alphanumeric and numeric and 10-16 form the right of the 7 alphanumeric and numeric displays.

The jackpot (extra display on Taxi, Police Force and River Boat Gambler) is done by taking away 8 segments from the 16 segments. This results in 8 segments available for the lower display (only capable of displaying digits) and the jackpot uses the other 8 segments (also only capable of displaying digits). The first (single) jackpot display uses strobes 2-8 and the second display (on River Boat Gambler) uses strobes 10-16. They are both only 7 numeric displays.

Quoted from slochar:

Ed Cheung's williams tester from a long time ago used a small 2x20 display to show the displays, and that was way back when, so definitely doable that way, although that was probably a system7 or 9 tester - so no extended segment data to worry about there.

System 7 and System 9 is only capable of displaying digits. The digits are encoded using BCD (binary coded decimal). It's essentially a hexadecimal digit (4 bits). There is a decoding IC (4543 or 4558) that takes the 4 bit input and outputs the digit segment configuration for use in a 7-segment digit display. There are two BCD digits (upper and lower) for a total of 8 bits of data.

#13 65 days ago

Here's the pic I used from a previous project detailing the segment data - the numbers are the bit position in the byte that feeds the display, all the ones with the ' single quote are one byte and the ones without are the other (mostly 7 segment data, except for d')

display segment info (resized).png
#14 65 days ago

I believe pinball designer Scott Danesi converted his Earthshaker to newer style displays. I think he replaced the boards with a P-Roc system and had both original and modified rules. He's the most experienced person with this kind of thing that I know of.

#15 64 days ago
Quoted from DakotaMike:

I believe pinball designer Scott Danesi converted his Earthshaker to newer style displays. I think he replaced the boards with a P-Roc system and had both original and modified rules. He's the most experienced person with this kind of thing that I know of.

He used a System 11 P-ROC adapter/driver board that included display support. The board was designed and sold by pinsider Snux. He is still active on the boards.

#16 59 days ago

Hey Guys,
Just to clarify what I did with Earthshaker. That game is using a regular alphanumeric display attached to the auxillary port of the P-ROC and using an adapter made by Jim Askey. snux designed the driver board that I used that replaced the System 11 main MPU board.

I did not put a DMD or LCD in that game.

--Scott

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