JVS input for retail systems? What's holding us back?

Discussion in 'Chihiro Development' started by leetwolf, Jul 18, 2018.

  1. leetwolf

    leetwolf Peppy Member

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    So my biggest thing with Chihiro is not so much running games on retail, but the gun input.
    I know JayFoxRox made the Chihiro loader but am I right in assuming that won't interface over the LPC for gun support? Calibrating isn't an issue as I already have a Chihiro working. But they are sensitive so I'm looking towards the future.

    Ultimately my question is, why can't we use the JVS input already?
     
  2. obcd

    obcd Rapidly Rising Member

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    The chihiro jvs interface is located on the baseboard.
    That board contains 2 microcontrollers AN2131QC and AN2131SC. Those interface to the chihiro main board using controller ports 3 and 4.
    The fun part is that they get their firmware (program) over the usb bus as well. So most games load a different firmware into these controllers before the game starts. The microcontrollers don't only provide the JVS interface, they also interface to a real time clock chip and some IIC eeprom memory used to store settings like high scores and system region. The firmware updates gmes are loading are hopefully only bugfixes.
    So basically you need to emulate 2 usb devices and provide a JVS interface. The easiest approach might be creating some hardware with modern microcontrollers like arduino atmega ones that appear to the system like the original base board does. As it interfaces to gameport 3 and 4, it could be a device external to the xbox. I doubt however the demand for such would be high enough to rectify it's design. Besides, it's mostly the mainboard that goes bad in a chihiro, which is why I work on an option to replace that.
     
  3. Syclopse

    Syclopse .

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    Could you add pictures of both boards and the JVS connection you're trying to reproduce? I'll have to double check but I believe my BETA XDK (DVT3) has a JVS port.
     
  4. leetwolf

    leetwolf Peppy Member

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    That would be awesome, I can't lie. I have bullet proofed my Chihiro. I replaced the fan heatsink on the GPU with a 1.6 heatsink and added a heatsink on the MCPX2. Also thermal pasted the GPU.

    I assume presently we don't know how to send the request over usb 3 and 4? We'd probably need a usb sniffer? I was under the impression the jvs input just did analogue controllers?
     
  5. obcd

    obcd Rapidly Rising Member

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    The mame chihiro driver gives a good idea how communication with the baseboard is working. They emulate all that.
    Did your 1.6 heatsink fit under the base board? I was under the impression it touched the base board.
     
  6. smf

    smf mamedev

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    JVS looks like USB, but it's rs485. They used the connectors because they were cheap and readily available.
     

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