• After working with @ironic on the RGB-Pi project for Recalbox now I'm starting a bigger challenge, to create a jamma adapter for RPi fully integrated with amplified sound, buttons, rgb and power all through the gpio without any additional cable.

    I have some progress made, for the video we use mode 3 of the DPI output of the Pi, this leaves us free the outputs GPIO9, 10 and 11 where we will connect two MCP23S17 with which we will introduce the buttons, a pin is needed for the CE Or CS (ChipSelect) at the moment use pin 8 that currently belongs to a bit of the RGB blue channel, later we must move this CS to another pin, it is the only pin with the ability to move and this is the only combination of hardware to do everything through the GPIO and I have been studying it for a long time.

    This is the prototype:
    alt text

    alt text

    Here a little video:

    To control the MCP23S17 by the SPI port I am using a ControlBlock2 drivers that are open source, but they are compiled in Raspbian, I need the way to integrate them into Recalbox or control the MCP23S17 by different way, at this point I need a Little collaboration from the Recalbox Devs.

  • @atg why use SPI instead of I2S ? I2S already works perfectly. You could just write an overlay that leaved you the i2s interfzce fir video/sound, no ?

  • @substring I2S use these pinout right?

    GPIO 18 (Pin12) is BITCLOCK;
    GPIO 19 (Pin 35) is LRCLOCK;
    GPIO 20 (Pin 38) is DATA IN;
    GPIO 21 (Pin 40) is DATA OUT; (probably not needed for buttons)

    These can be compatible with the DPI output for RGB in mode 4 but interfering with the audio PWM output at GPIO19 or 18.
    RB can handle MCP23S17 by this port? I see HiFiBerry use these same port, I don't know if is possible use two different functions by the same port, and if is possible you need a DAC and more hardware for the sound and sure you need use the GPIO21 for data out and these collide with the DPI 😕

  • @aTg no it uses pins 3 5 27 28 source : https://fr.pinout.xyz/pinout/i2c

  • In fact pins 3 and 5 are enough

  • @substring Aaa ok I2C not I2S, I need GPIO3 for h_sync an 5 for one bit of blue.

    The DPI is not negociable.

    I study all the option for a long time, the only way is use SPI and move CS.

    Now before the launch of the 4.1 not is possible compile ControlBlockService2 into the release?

    These drivers give support for JAMMA-Pi and ControlBlock at the same time.

  • @atg The real deal would be to add SPI support to the gpio arcade driver that ships with recalbox. There is no point in adding controlblock, and definitely not in 4.1

  • @substring Ok, it seems a good way, the only important point is that the integration of the SPI port allows to move the CS pin in any GPIO, this can be done, there are several examples but I do not know how it would have to be done in RB, this point Is the key part of the whole project.

  • This is a preview of the final aspect of the adapter.

    alt text

    The idea is reach a low-cost product for 30€ without any extra cables needed.

  • @Substring and other members of Recalbox , please give support to @aTg , he is doing an amazing job with Rgb-Pi (scart solution) and he will do the same with Jamma-Pi

    @atg said in [PROJECT] JAMMA-Pi:

    This is a preview of the final aspect of the adapter.

    alt text

    The idea is reach a low-cost product for 30€ without any extra cables needed.

    Wow, that's an important effort.

  • Adding SPI to the gpio driver is quite a big task 😕

  • @substring Can I offer a bounty to contirbute to the Recalbox project?

  • Hello,
    I have not tested, but there is an overlay to reroute the pins cs0 and cs1.

    see on /boot/overlay/readme :

    Name: spi0-cs
    Info: Allows the (software) CS pins for SPI0 to be changed
    Load: dtoverlay=spi0-cs,<param>=<val>
    Params: cs0_pin GPIO pin for CS0 (default 😎
    cs1_pin GPIO pin for CS1 (default 7)

    put in /boot/config.txt , the line :

    dtoverlay=spi0-cs, cs0_pin <n°pin>

    there is another way : software i2c with dtoverlay i2c-gpio

    Name: i2c-gpio
    Info: Adds support for software i2c controller on gpio pins
    Load: dtoverlay=i2c-gpio,<param>=<val>
    Params: i2c_gpio_sda GPIO used for I2C data (default "23")
    i2c_gpio_scl GPIO used for I2C clock (default "24")
    i2c_gpio_delay_us Clock delay in microseconds
    (default "2" = ~100kHz)

  • @llegoff I'm going to discard the SPI prorotype and make another based on i2c because I think with this bus is possible move all the pins.

    Thanks for your participation.

  • Well I'm back again with the project, following the recomendations of @Substring I change the prototype to allow one MCP23017 conected by the port i2c to talk with Recalbox, I add to the circuit one RGB-Pi PCB for the video output and here is the little frankenstein.

    alt text

    alt text

    I use the overlay i2c-gpio to move the pins from 2, 3 to 10 , 11


    Now is the moment to enable the option en recalbox.conf, I thing the work is made by mk_arcade_joystick_rpi included but I read in the repo "The branch hotkeybtn now support one more button per player in place of MCP23017 support" and the scheme don't show any pin for i2c, this would be say not longuer avaible use i2c for controllers?

    I try to activate on recalbox.conf

     # ------------ D2 - GPIO Controllers ------------ #
    ## GPIO Controllers
    ## enable controllers on GPIO with mk_arcarde_joystick_rpi (0,1)
    ## mk_gpio arguments, map=1 for one controller, map=1,2 for 2 (map=1,map=1,2)

    But the program interfiring with the video output, and I don see what can be user to talk by i2c...

    I need a little help from the Devs to talk with Recalbox by i2c and pins 10 & 11, any help is much apreciated!

  • @atg i2cdetect ?

  • Anyway, the module needs some more parameters in the recalbox.conf, see https://github.com/recalbox/mk_arcade_joystick_rpi#more-joysticks-case--mcp23017

  • @substring said in [PROJECT] JAMMA-Pi:

    @atg i2cdetect ?

    I thing i2cdetect don't detect nothing, I got this message:

         0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
    00:          -- -- -- -- -- -- -- -- -- -- -- -- -- 
    10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
    20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
    30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
    40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
    50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
    60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
    70: -- -- -- -- -- -- -- --                

    I follow the steps from the readme, my setup on the addresses of the chips in A0 A1 A2 are 000 in one and 100 in the other, I try only with one chip on 000 and the same result, when a run modprobe mk_arcade_joystick_rpi map=1,0x20 the i2c port is enabled on pin 2 or 3 and not on 10, 11 and lose the sincronism of the image.

    This can be made because the driver acces to the ports by harware and don't use the DeviceTreeOverlays.

  • @ian57 would you ever have some time to take a look at i2c gpio remapping and the kmk_arcade_gpio module ?

  • Staff
    Global moderator

    @substring ok will do that during christmas holydays
    I will have som etime. please remind me through Slack 😉 or I will put an issue

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