Keyrah and MK3

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Don't Panic. Please wash hands.
  • Hi Folks,


    I am planning to drop one of my A1200's into a Checkmate case. The A1200 has a MK3 and will also need a Keyrah. Has anyone got a way of using both and retaining the excellent live edit feature of the MK3?

  • Keyrah will turn the Amiga keyboard into a USB keyboard, so it can be used with an RPi or other PC/Mac.


    You probably mean Lyra, which makes PS2 keyboards available to the Amiga? If so, then yes, live edit works with that. Lyra has supported pressing multiple keys at the same time from day one.

  • Jens

    Maybe he has also as SUM Adapter to use a USB Keyboard with the AMIGA (like I do).

    The Problem is: If you want use the Original AMIGA Keyboard with the Checkmate Case you have only the Keyrath Adapter if you have an A1200 For the A500 its much easyer because here the Keyboard has an own Chip and only some wires, but the A1200 has no Connectors for this Signals, so buying a A500 Keyboard is also no option.

    As I have read in antoher thread, you plan a new version of the Keyrath because Chip shortage. Maybe this Version can also make a PS/2 Keyboard with the Original Amiga Keyboard, so we can use the LYRA Adapter with the Keyrath.

  • Hi, right now I dont have any kind of adaptor - just planning out the move to a checkmate case. Sounds to me like my only option to retain the full functionality of the MK3 is to go with Lyra - PS2 out of the mainboard and then use a vanilla PS2 keyboard - rather than converting the amiga A1200 keyboard over with the Keyrah.

  • Well, my opinion about the Checkmate case is well-known... make sure you're using a DC-DC converter-based power supply. Anything else will cause lots of pain locating an error that seemingly wanders with new hardware installed.


    Sounds to me like my only option to retain the full functionality of the MK3 is to go with Lyra - PS2 out of the mainboard and then use a vanilla PS2 keyboard - rather than converting the amiga A1200 keyboard over with the Keyrah.

    Yes, that is one option. I do not know how the SUM adapter handles multiple keys at the same time, but knowing that n-key-rollover is a whole different protocol on USB, my expectation is that it won't use that mode. Our plan, however, is to implement that mode for Keyrah V3, because the Amiga keyboard is capable of making a difference of up to 15 keys (including qualifiers). I'd like the product to reflect the capabilities of the physical hardware - and that will be an improvement over Keyrah V2. Note that the n-key rollover mode on USB is an optional protocol, so the standard USB protocol will always be supported. This will work with all adapters and computers, though with the limitation of max. six keys pressed at the same time. This is very likely to be sufficient for the live config function of Indivision AGA MK3.


    Conversion back to the Amiga is something we've thought about as well. PS2 has the huge benefit of very small protocol overhead and supporting n-key rollover "out of the box", so playing games with the keyboard that require multiple keys pressed at the same time is easily possible with Lyra 3 and a good keyboard. For a next-generation Lyra (which is purely hypothetical by now), a much more complex USB handling would be required in order to support n-key rollover. Since PS2 covers that all, the most sane way to solve this problem would be to add the PS2 protocol into Keyrah V3, so it will be able to interface with Lyra3. I'll talk to Tobias - he's assigned to the firmware of Keyrah V3.

  • Well, my opinion about the Checkmate case is well-known... make sure you're using a DC-DC converter-based power supply. Anything else will cause lots of pain locating an error that seemingly wanders with new hardware installed.

    I think, the case is not the Problem. The problem is the PSU and for the A500 Mainbaord the Extension Board.


    I plan (my case is still in the basement since the relocation) to use the CA-PSU with the 12V from the SFX PSU because with an A1200 you have to run cables to the outside anyway to supply the board with power. (So I can also use the CA-PSU). Also, my PSU is very Small (200 W) so the 5V Rail is (I hope) stable.

    I do not know how the SUM adapter handles multiple keys at the same time, but knowing that n-key-rollover is a whole different protocol on USB, my expectation is that it won't use that mode.

    I have never checked this. But it's always interesting what I can learn in this 'support forum'.

    Since PS2 covers that all, the most sane way to solve this problem would be to add the PS2 protocol into Keyrah V3, so it will be able to interface with Lyra3.

    This will be very nice and for me a reason te rebuy the Keyrah and a Lyra Adapter (But Maybe I show, where I can find the Signals from the A500 Keyboard. I think, they are on the Same Chip as the Lyra Adapter Used. So I can maybe also Use a A2000/3000/4000 Keyboard (which, If I have seen it right, all use the Same KEY-CLK and KEY-DATA Lines like tha A500 Internal).