Tag Archives: hardware

Mega PC tower and Book

I’ve printed two books using the Lulu service. (One for Tyrone)
When they arrived, I noticed some faults.
Lucky Lulu will be printing them again for me.

The book has over 500 pages and has a nice hardcover.

And I’ve been busy building a Mega Tower with 4 Motherboards.
This will have a superb processing power! .. not.
It houses some old motherboards for hardcore machine coding on real old hardware.

From top to bottom: 8088, 8086, 80386, 80484

Todo:

  • Rework on the cables
  • 3D print an information plaque on the front of each board
  • Add a control panel on each board
  • Maybe some dust cover would be nice

I can remove the boards, and place them on a table.
I’ve made some custom feet for them. Twist and lock by my own design.

Padded feet

The openscad files:

The locking is done by making the cylinder slightly oval by 0.5mm

difference(){
	difference(){
		difference(){
			difference(){
				rotate([90,30,0])
				cylinder(r=30, h=10, $fn=3);
				translate([-20,-20,0])
				cube([40,40,40]);
				}
			rotate([90,0,0])
			translate([0,0,-10])
			cylinder(r=5, h=30, $fn=200);
			translate([0,-5,-10])
			cylinder(r=7, h=30, $fn=200);
			}
		translate([18,-5,-12])
		cylinder(r=4, h=30, $fn=200);
		translate([18,-5,-22])
		cylinder(r=2.2, h=30, $fn=200);
		translate([-18,-5,-12])
		cylinder(r=4, h=30, $fn=200);

		translate([-18,-5,-22])
		cylinder(r=2.2, h=30, $fn=200);
		}
	translate([9,-20,-20])
	cube([40,40,40]);
}

Note the resize for the oval effect

resize([14,14.5,10])
cylinder(r=7, h=10, $fn=200);
translate([0,0,0])
cylinder(r=9, h=3, $fn=200);

When designing above, I also made new knobs for our stove.
Using the white dot, you can see which burner has which knob.

Old and new chips SMD or THT?

I’ve got two friends who make old retro computers.

They like to use old chips and use only THT.

What is my take on this?

I like to use THT when possible. Exceptions are:

  • Size constrains
  • No THT parts available
  • New gadgets

Old versus new chip solutions

  • CPU : never a new alternative
    (I’m not going to replace a 6502 using Arduino emulation, for example)
  • Yes, I’m using static ram instead of dynamic
  • Address decoder using 74xx ? Yes, I want to test at least once.
    But using a ATF22v10 has my preference. (Not using GALs anymore)

I only replace with newer alternatives when it does NOT interfere with how a system is performing. CPU has its own quirks, also chips like the SID. I never emulate when it can be avoided.
Address decoding, RAM or ROM yes please 🙂
Old untrusted UV Eproms are sh*t. Give me the new flash-able alternatives any time

I can emulate everything, but I need real hardware.

  • Real 6502
  • Real 68000
  • Real 8088
  • Real 8086
  • Real 80386

I still want a real VGA monitor because I used to write VGA manipulation programs which only work on CRTs.

68000 Progress

UPDATE 20240927 PCBs are in

While testing on a breadboard is fast, I still want my 68000 on PCBs.

Breadboards are nice for testing, and I use them in the design stage.
But they will fail in the end.
Loose wires, oxidated contacts and alike.

So when I was testing using breadboard, I drew the schematics in KiCad.

I wanted to use Eurocards for this one. If I divide the whole system in system blocks, I can exchange and experiment parts.
(My 6502 uses another method to connect different cards)

  • CPU and Clock (Plus power-on reset and step mode)
  • Memory and ROM
  • Storage
  • Address decoding
  • Sound
  • IRQ Handlers
  • Led Blinkenlights 🙂

I wrote about Eurocards in the past.

So I’m using the VMEbus standard for my new design.
(Using the recently bought book I mentioned)

Backplane design is done. And currently being autorouted.

PowerLeds for 5 and 12V. On/Off switch and MOLEX power connector.

Kicad sources will be uploaded

Freerouter with in the background a part of the CPU Card I am redesigning.

In the past, I dumped my old eurocards and even a nice case I had.

UPDATE 20240927 PCBs are in

Made a Meatloaf device for C64

Awesome opensource project

https://github.com/idolpx/meatloaf-specialty/tree/main

  • Emulates a floppy drive: Meatloaf plugs into the Commodore 64’s IEC serial port and acts like a virtual floppy drive. This allows you to load software and data stored on its internal flash memory, sd card, or stream it via WiFi using various protocols from servers all over the world.
  • Supports multiple virtual drives: Unlike a single floppy drive, Meatloaf can be configured to emulate up to 26 virtual drives (IDs 4-30). Each virtual drive can have a different disk image loaded, essentially offering the equivalent of having thousands of floppies connected to your C64.
  • Supports additional virtual device types: Printers, a network interface, and more.
  • Connects to the internet: Meatloaf also functions as a WiFi modem, enabling your Commodore 64 to connect to Telnet BBS (bulletin board systems) for communication and sharing information.

https://meatloaf.cc/sc/s/shortcodes.php

Load a prg using a url

LOAD"HTTP://C64.ORG/GAMES_AZ/H/H.E.R.O.PRG",8

Or from a D64 image on your own Windows/Samba server (all known CBM image formats supported):

LOAD"SMB://STORAGE/C64/FAVORITES/PIRATES_A.D64/*",8

Load a random game from the internet

LOAD"ML:ARCADE*",8	

Reverse engineering Newton wars, giving it my own twist.

Saw a cool game a while ago, and found some old code.
There was no schematic, so I had to reverse engineer it using the Arduino code.
This one uses a Micro Pro.

Build a working version, now I can use this as base to create other games.
But first i’m going to rebuild it so it can use Wifi and uses a Lipo Battery. Making it usable without wires.

  • Rotary – set angle/speed (Press resets)
  • Blue – toggle angle or speed ( was rotary press )
  • Green – select digit to change
  • Red – Fire
  • Led – not completely working yet, shows color of player
    Wil be changed to addressable leds with more functions
    (Player color, energy warning and more)

Next to do:

  • Build a Wifi version with Lipo
  • Build permanent version in a case
  • Build 2nd 3th or more controllers
  • Create own games

Bornhack 2023 NFC Badge Display hack

Last week I bought an old Bornhack Badge. I thought it needed a display.

Using a SSD1306 display, and Circuitpython I made this.

( Wooded thingy contains an RFID chip ( Part of my player ))

Library and files needed:

  • font5x8.bin in root of filesystem ( just google for this file )
  • copy of adafruit_framebuf.mpy in /lib
  • copy of adafruit_ssd1306.mpy in /lib

Code: (midway some pixel examples, just uncomment)

import board
from time import sleep
import busio 
from PN7150 import PN7150
import adafruit_ssd1306
import math
import adafruit_framebuf


if True:
    # Fast 400KHz I2C
    i2c = busio.I2C(board.SCL, board.SDA, frequency = 400000)
else:
    # Regular 100kHz I2C
    i2c = board.I2C()


WIDTH = 32
HEIGHT = 8

buffer = bytearray(round(WIDTH * math.ceil(HEIGHT / 8)))
fb = adafruit_framebuf.FrameBuffer(
    buffer, WIDTH, HEIGHT, buf_format=adafruit_framebuf.MVLSB
)


nfc = PN7150(i2c, board.IRQ, board.VEN)

display = adafruit_ssd1306.SSD1306_I2C(128, 32, i2c,addr=0x3c)

assert nfc.connect()
print("Connected.")

assert nfc.modeRW()
print("Switched to read/write mode.")

display.fill(0)

display.show()

#display.fill(0)
#display.text('Hello', 0, 0, 1 )
#display.text('World', 0, 10, 1)
#display.show()
# Set a pixel in the origin 0,0 position.
#display.pixel(0, 0, 1)
# Set a pixel in the middle 64, 16 position.
#display.pixel(64, 16, 1)
# Set a pixel in the opposite 127, 31 position.
#display.pixel(127, 31, 1)
#display.show()

while True:
    display.fill(0)
    display.text('Waiting for card', 0, 0, 1 )
    display.show()

    assert nfc.startDiscoveryRW()

    print("Waiting for card..")
    card = nfc.waitForCard()
    assert nfc.stopDiscovery()

    print("ID: {}".format(card.nfcid1()))
    id = card.nfcid1()
    display.text(id, 0, 10, 1 )
    display.show()

    sleep(0.5)

Not sure about display i2c address? Use below code

import time
import board
import busio

# List of potential I2C busses
ALL_I2C = ("board.I2C()",)

# Determine which busses are valid
found_i2c = []
for name in ALL_I2C:
    try:
        print("Checking {}...".format(name), end="")
        bus = eval(name)
        bus.unlock()
        found_i2c.append((name, bus))
        print("ADDED.")
    except Exception as e:
        print("SKIPPED:", e)

# Scan valid busses
if len(found_i2c):
    print("-" * 40)
    print("I2C SCAN")
    print("-" * 40)
    while True:
        for bus_info in found_i2c:
            name = bus_info[0]
            bus = bus_info[1]

            while not bus.try_lock():
                pass

            print(
                name,
                "addresses found:",
                [hex(device_address) for device_address in bus.scan()],
            )

            bus.unlock()

        time.sleep(2)
else:
    print("No valid I2C bus found.")

Keyboard switcher part 2

I’ve connected the rotary encoder directly to the zero.
Although many websites state that you need pull-up resistors, there is no need. Just use the internal pull-up resistors in the Pi.

Example code

        GPIO.setmode(GPIO.BCM)					# Use BCM mode
        GPIO.setup(self.24, GPIO.IN, pull_up_down=GPIO.PUD_UP)
        GPIO.setup(self.25, GPIO.IN, pull_up_down=GPIO.PUD_UP)
NOTE: Between 24 and 25 is a GND connection

Besides USB HID below XT, C64 and Amiga connectors will be emulated

PCBs !

Got my new PCBs in.

My Bus Manipulator, Backplane for 6502, and C64 PLA replacement.

I’m selling the leftover PCBs if you are interested.

These are not the final versions.
They should work, but they lack holes for stand-offs or feet.

Example setups for the backplane.
Using a flatcable or direct connection to my 6502 SBC.

The backplane was designed to be chained together.
(Horizontal female – male connection)

The vertical cards I’ve planned to make are:

  • ACIA – Serial Interface
  • Sound Card (SID/AY-2-8910)
  • External Display
  • ?