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Found 2 results

  1. Hi! I'm working with porting an FPGA design with a soft core CPU to the Nexys A7 100T board. The CPU's SW is polling a PS/2 keyboard each 16ms by releasing the PS2_CLK (changing the pin 0->Z, i.e. inhibit release) during ~100µs. This works fine on the earlier design that uses a real PS/2 keyboard, but it fails with using the USB -> PS/2 emulation on the Nexys A7 board. A deeper investigation shows that real PS/2 keyboard responses with lowering the PS2_CLK signal 25-35µs after the CPU has change the PS2_CLK pin 0->Z, while the Nexys PS/2 emulation seems to require up to 420µs before it responses. What is the specified max response time after inhibit for the PS/2 emulation implementation? Would it be possible to have a FW update that lowers this time? I also noted that the link to the Release page under "Demo Setup" on https://github.com/Digilent/Nexys-A7-100T-Keyboard points to the wrong URL (I assume that the correct URL should be https://github.com/Digilent/Nexys-A7-100T-Keyboard/releases) and the demo shows the keyboard code on the 7-segment display, not via the serial port. Best regards, Per-Olof
  2. Hi, I've recently got a Nexys 4 DDR and I'm trying to find a keyboard that works with it. Any mouse I have works, so I'm assuming the USB connector and the PIC24 are all soldered on properly and working. I know that older and/or 'simple' keyboards are supposed to work but so far I haven't found any that actually do. I'm still looking, and I've ask around (on this forum and elsewhere) for specific make/models that are know to work. In the meantime, I've observed that when I connect the keyboard I'm using right now to type this post to the Nexys4 DDR, and run the Nexys-4-DDR-Keyboard, I keep getting 0xAA messages. If I keep a key pressed for a long time, sometimes I observe the proper scancode for the key, and then it's endless 0xAA again. According to the Nexys4 DDR reference manual: "When a keyboard or mouse is connected to the Nexys4 DDR, a “self-test passed” command (0xAA) is sent to the host." What I think is happening is that keyboard or the connection with the keyboard keeps getting reset by the PIC, which continuously sends 0xAA codes when it re-detects the keyboard. I was wondering if anyone knows what code the PIC24 is executing, if there are any patches for it, or if it's possible to see the source code to maybe fix this problem or improve compatibility. As it is, using a Nexys4 DDR is *really* hard because very little modern hardware seems to work with it. Thanks!
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