• Yet another keyboard

    jaromir.sukuba02/24/2016 at 09:23 2 comments

    Though the old Tesla keybaord I described here and here and described by @Benchoff in #Metal Dome Keyboard is still in my drawer in amount higher than small, I'm looking for alternatives for my MiniBSD.

    I found one in here, for the case the listing is unavailable, here is screenshot

    I dissected the thing on arrival and didn't bother whether it works or not

    There is nothing but 20x8 cm keyboard matrix with 28-pin 1mm pitch FPC connector and tiny PCB containing USB controller

    With the testing pads it looks like perfect breakout board for testing, after cutting the epoxy blob. The keyboard itself looks quite usable and has nice feel

    there are rubber domes under each key and mechanical support

    There are 25 pins used on the 28-pin flex cable, checking all the combinations manually with multimeter would be quite annoying, so I decided to build a test rig.

    Not the cleanest example of engineering work, but for quick testing it is adequate. There is PIC16F1519 on board, testing all combinations of wires for conductivity few times per second and pushing results via serial port. Not exactly interesting thing, but quick and ugly test sources will be available for download in the "files" section.

    After a few minutes of poking the keys and noting the results, I got this nice table

    where line 11 is unused, being apparent on pictures above - or translated into keyboard layout

    For example, pressing key Q connects lines 20 and 7.

    The layout in .xlsx format is available in single package with pictures and sources of test rig.

  • 4.4 BSD-Lite

    jaromir.sukuba12/29/2015 at 00:23 2 comments

    Well, it's a long time since last update. Today, I sat down to my new board around PIC32MZ2048ECG064

    and configured/complied/loaded LiteBSD system to run on it from internal RC oscillator

    Copyright (c) 1982, 1986, 1989, 1991, 1993
    	The Regents of the University of California.  All rights reserved.
    
    4.4BSD-Lite build 0 compiled 2015-12-28
        jarin@plechac:LiteBSD/sys/compile/SDZL.pic32
    cpu: PIC32MZ2048ECG064 rev A5, 200 MHz
    oscillator: system PLL div 1:2 mult x50
    cache: 16/4 kbytes
    real mem = 512 kbytes
    avail mem = 352 kbytes
    using 18 buffers containing 73728 bytes of memory
    spi1 at pins sdi=RF1/sdo=RF0/sck=RD1
    spi2 at pins sdi=RG7/sdo=RG8/sck=RG6
    spi3 at pins sdi=RB9/sdo=RB3/sck=RB14
    spi4 at pins sdi=RD11/sdo=RD0/sck=RD10
    uart1 at pins rx=RD2/tx=RD3, interrupts 112/113/114
    uart2 at pins rx=RB7/tx=RB6, interrupts 145/146/147, console
    sd0 at port spi2, pin cs=RG9
    sd0: type I, size 498176 kbytes, speed 12 Mbit/sec
    sd0a: partition type b7, sector 2, size 204800 kbytes
    sd0b: partition type b8, sector 409602, size 32768 kbytes
    sd0c: partition type b7, sector 475138, size 102400 kbytes
    bpf: lo0 attached
    WARNING: preposterous clock chip time -- CHECK AND RESET THE DATE!
    
    starting file system checks.
    /dev/rsd0a: 2128 files, 13973 blocks used, 36242 free
    /dev/rsd0a: MARKING FILE SYSTEM CLEAN
    starting network
    clearing /tmp
    standard daemons: update.
    Mon Dec 28 15:44:43 PST 2015
    
    
    4.4BSD-Lite (bsd.net) (console)
    
    
    
    login: root
    Last login: Mon Dec 28 15:44:00 on console
    Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994
            The Regents of the University of California.   All rights reserved.
    
    4.4BSD-Lite UNIX #1: Fri Apr 01 00:00:00 PDT 1994
    
    Welcome to 4.4BSD-Lite!
    
    erase ^H, kill ^U, intr ^C status ^T
    Don't login as root, use the su command.
    # 

    This is more powerful system than previous one with PIC32MX - only 128kB RAM / 80MHz compared to 512kB RAM and 200MHz of PIC32MZ, not mentioning new OS, so I'm definitely going to employ this MCU on MiniBSD computer.

  • New keyboards layout

    jaromir.sukuba10/03/2014 at 18:44 0 comments

    Well... four months since last update... the time flies. Brian Benchoff asked about the new keyboard layout, so here is my quick and dirty "drawing" in LibreOffice Calc.

    When Q key is pressed, there is contact on between pins 1 and 6. After pressing J, between 9 and 14. You got the idea.

    It is not very likely to obtain the keyboard outside Czech or Slovakia, though Brian got this keyboard in Apex electronics, LA. However, I managed to get my hands on a few pieces of those keyboards, so I'll be able to source it to interested builders, if any.