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Using an MSP-430 to control a early 6800CPU pinball machine

Kevin Moore
Prodigy 100 points

Other Parts Discussed in Thread: SN74HC595, SN74HC165, PCF8574

I'm wondering if one of the MSP-430 launchpads could be used to develop a MPU board to control a pinball machine. I know this has been done with the likes of the Arduino Mega, and Pic32 Chipkit. 

New to this, and just by looking at the Mega it appears to have considerable more inputs/outputs than the launchpads. 

This is the schematic of the board I am trying to duplicate showing the inputs for the switch matrix's, solenoid controls, and lamp matrix's 

Would this be possible?

Thanks, 
Kevin

  • 0
    Guru 58965 points
    I think the problem is there is no longer people that is capable of writing the code for such pin-ball machines.
  • 0
    Guru 74080 points

    Hi Kevin!

    Sure a LaunchPad can be used for this, but of course you are more flexible when using a microcontroller on a custom board. But a pinball machine has a lot of relatively slow ON/OFF functions like bulbs, solenoids and display segments. Those can easily be controlled by serialized SIPO registers (serial in parallel out) like the SN74HC595, for example. In theory, there is no limitation in the quantity of serialized SIPOs, so the number of usable outputs is up to you as well. There are equivalent parts for combining multiple inputs to a serial bitstream, too. So yes, a LaunchPad could do the job, although not all pins of the LaunchPads processor are available.

    Dennis

  • 0 in reply to Dennis Eichmann
    TI__Prodigy 100 points
    As far as the lamps are concerned the driver board already has 5 MC14514B 4-16 decoders. I may at some point design a custom board with all the interface chips I need. Right now this is more a of a proof of concept to see what's capable with the 430

    Kevin
  • 0 in reply to old_cow_yellow
    TI__Prodigy 100 points
    The code would be written by me. The game logic on the earlier games is not crazy complicated. Hit this switch, Light this light, score this many points. The whole point of this is to make a customizable game with rules that can be changed.

    Kevin
  • 0 in reply to Kevin Moore
    Guru 74080 points
    If you are asking if the processing power of a MSP430 is sufficient, then the answer is yes.
  • 0 in reply to Dennis Eichmann
    TI__Prodigy 100 points
    I think Using a couple of 74HC165's would be a good way to get the inputs from the switch matrix. get 16 inputs down to 3 lines.

    Kevin
  • 0 in reply to Kevin Moore
    Guru 74080 points

    Kevin Moore said:
    SN74HC165

    Yes, this one could be used. There are also I²C connected parts like the PCF8574, for example. It is up to you. I prefer SPI rather than I²C.

  • 0 in reply to Dennis Eichmann
    TI__Prodigy 100 points

    I may have to do some re-thinking. I've started to re-draw the schematics or at least the interface portions of the boards that I need the 430 to interface with. I haven't drawn up the 7 segment display interface yet, that should take another 7 or so outputs and a strobe. 

  • 0 in reply to Kevin Moore
    TI__Prodigy 100 points

    Ok, So I think I should be able to use a couple of MCP23S17 chips to interface the MSP-430FR5994 Launchpad to my existing boards. The layout is almost identical to the 6821 PIA chips originally used. 

    So I have the switch Strobes on GPA0-6, Switch Returns on GPB0-7

    Then I have the Lamp Addressing on GPA0-3, and the Lamp Data on GPA4-7

    My next problem is trying to figure out trying to figure out how the CA1 and CA2 worked on the old 6821 PIA, and how to duplicate that, as it's used for the Lamp Strobe, and is also used on the 7 digit Display interrupt, and display strobes. 

    Can someone point me in the right direction on some reading material or explain how I might handle these signals? I've included a rough schematic of what I'm trying to do. If you would like a better version of it, or the Eagle Cad SCH file let me know. 

    Thanks, 

    Kevin

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