Hi Didier, On Tue, Jun 30, 2015 at 10:07:06AM +0200, Didier Derny wrote: >I'm working on usb/bluetooth keyboard for several machines >I wanted to detect when the commodore is starting to scan the keyboard I wonder if the â€˜gaming keyboardsâ€™ are assigning one GPIO pin per key. I wouldnâ€™t consider it unthinkable. If your goal is to connect the old keyboards to newer devices, you canâ€™t of course ditch the keyboard matrix. If not, skip to the quoted text below. What you could do is that you could improve the keyboard scanning. Some 20 years ago, I made some experiments on the C128. I found that making the outputs to all-1 between each scan iteration would reduce the shadowing. Another idea that you could do is to read the matrix from â€˜both directionsâ€™ (first driving the columns and reading the rows, then driving the rows and reading the columns). Remember that you have a dedicated CPU for the keyboard, and not just a few hundred 6502 clock cycles in a timer interrupt. Also, did you check the article in the C=Hacking Issue #6 about keyboard scanning: http://codebase64.org/doku.php?id=magazines:chacking6 >1 usb keyboard or 1 windows application controlling a C64 or a tandy >coco 1/2/3 the same board can fit a coco 3 or a C64 or VIC 20 (just >different connectors) the communication is done via serial bluetooth > >a prototype works on a breadboard, I make a first PCB in a few days Hmm, this seems the opposite route: using a modern keyboard with old hardware. I thought that Jim Brain already has something for this application. AFAIU he is controlling a programmable switch matrix with a microcontroller. If you know which way the software is reading the keyboard matrix, you can theoretically replace it with something simpler, such as essentially a RAM that connects address lines to columns and data lines to rows, or vice versa. Instead of address and data lines, you might even use the GPIO lines of a fast enough microcontroller, and maybe implement Pin Change Interrupt on those lines. Marko Message was sent through the cbm-hackers mailing listReceived on 2015-06-30 09:00:44
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