Working on a demo part

Started coding a demo with a friend of mine.

I made a part that uses raster interrupts and gives the illusion that the picture is up in the border.

  • Opening the borders
  • Changing the border colour midway
  • Using NOPs to get a stable rastersplit
  • Sprites in the border
  • Fixing the sprite mirroring in the bottom part
  • Learning a lot about bad raster lines, I had to make a lot of workarounds to get it working

Hopefully I’ve got some rastertime left to play music. But I learned a lot!
UPDATE: Yes also with SID music!

Not shown: Bad raster lines, split colors background and bordercolor.
Maybe I’ll add deze

LMS Record player V.something .. final? No

But it works! Many iterations .. almost perfect

Recordplayer model by kriswillcode, but heavily remixed

Record player is going to be re-printed at a higher quality.

  • Put a printed image on the player, and it plays the album
  • Move the arm, and the next track will be played
  • Press upper white button, and the music will pause/resume
  • Press lower button … ??? Don’t know yet

Updated python client (see previous posts)

import paho.mqtt.client as mqtt
import urllib.request
from time import sleep

def on_connect(client, userdata, flags, rc):  # The callback for when the client connects to the broker 
        print("Connected with result code {0}".format(str(rc)))  

def on_message(client, userdata, msg):  # The callback for when a PUBLISH message is received from the server. 
        print("Message received-> " + msg.topic + " " + str(msg.payload))  # Print a received msg
        if msg.topic == "spotify/rfid/idlms":
            urllib.request.urlopen("http://LMS-SERVER-IP:9000/anyurl?p0=playlistcontrol&p1=album_id:" + msg.payload.decode() + "&p2=cmd:load&player=00:04:20:16:d9:04")
        if msg.topic == "spotify/rfid/but1":
        if msg.topic == "spotify/rfid/but2":
        if msg.topic == "spotify/rfid/arm":

client = mqtt.Client("lmsclient")  # Create instance of client with client ID “digi_mqtt_test”
client.on_connect = on_connect  # Define callback function for successful connection
client.on_message = on_message  # Define callback function for receipt of a message
client.connect('MQTTSERVER', 1883)
client.loop_forever()  # Start daemon

Wemos INO file

#include <Arduino.h>
#include <SPI.h>
#include <MFRC522.h>
#include <ESP8266WiFi.h>
#include <WiFiClient.h>
#include <PubSubClient.h>
#define SS_PIN 15
#define RST_PIN 0

const int buttonPin1 = D1;  
const int buttonPin2 = D2;   

int buttonState1 = 0; 
int buttonState2 = 0; 

MFRC522 mfrc522(SS_PIN, RST_PIN);
  MFRC522::StatusCode status; //variable to get card status
  byte buffer[18];  //data transfer buffer (16+2 bytes data+CRC)
  byte size = sizeof(buffer);

  uint8_t pageAddr = 0x06;  //In this example we will write/read 16 bytes (page 6,7,8 and 9).
                            //Ultraligth mem = 16 pages. 4 bytes per page.  
                            //Pages 0 to 4 are for special functions.           
unsigned long cardId = 0;
WiFiClient net;
PubSubClient client(net);
const char* mqtt_server = "MQTTBROKER";
const char* ssid = "MYSSID";
const char* password = "MYWIFIPASWORD";
String topicStr = "";
byte buffer2[8];

boolean Rflag=false;
int r_len;
char payload[5];
byte value[5];
void setup() {
    pinMode(buttonPin1, INPUT_PULLUP);
    pinMode(buttonPin2, INPUT_PULLUP  );

  WiFi.begin(ssid, password);
  client.setServer(mqtt_server, 1883);
void reconnect() {
  while (WiFi.waitForConnectResult() != WL_CONNECTED) {
  while (!client.connected()) {
    String clientId = "rfid-";
    clientId += String(random(0xffff), HEX);
    if (!client.connect(clientId.c_str(), "rfidclient", "...")) {
void callback(char* topic, byte* payload, unsigned int length) {
   Rflag=true; //will use in main loop
   r_len=length; //will use in main loop
   int j=0;
     for (j;j<length;j++) {
if (r_len < 3) {
  Serial.print(F("Set false"));
buffer2[j]='\0'; //terminate string

void loop() {
    if (!client.connected()) {

buttonState1 = digitalRead(buttonPin1);
  if (buttonState1 == 0 ) {
    client.publish("spotify/rfid/but1", "0");
buttonState2 = digitalRead(buttonPin2);
  if (buttonState2 == 0 ) {
    client.publish("spotify/rfid/but2", "0");

int reading = analogRead(0);
  if (reading > 500 ) {
    client.publish("spotify/rfid/arm", "0");
  if (!mfrc522.PICC_IsNewCardPresent()) {
  if (!mfrc522.PICC_ReadCardSerial()) {
if (Rflag) {
        for (int i=0; i < 4; i++) {
    //data is writen in blocks of 4 bytes (4 bytes per page)
    status = (MFRC522::StatusCode) mfrc522.MIFARE_Ultralight_Write(pageAddr+i, &buffer2[i*4], 4);
    if (status != MFRC522::STATUS_OK) {

  cardId = getCardId();
  char buffer3[10];
  sprintf(buffer3, "%lu", cardId);
  client.publish("spotify/rfid/id", buffer3);

  status = (MFRC522::StatusCode) mfrc522.MIFARE_Read(pageAddr, buffer, &size);
  if (status != MFRC522::STATUS_OK) {
    Serial.println(F("MIFARE_Read() failed: (R)"));

  Serial.println(F("Read data: "));
  for (byte i = 0; i < 5; i++) {
  client.publish("spotify/rfid/idlms", buffer,5);

unsigned long getCardId() {
  byte readCard[4];
  for (int i = 0; i < 4; i++) {
    readCard[i] = mfrc522.uid.uidByte[i];
  return (unsigned long)readCard[0] << 24
    | (unsigned long)readCard[1] << 16
    | (unsigned long)readCard[2] << 8
    | (unsigned long)readCard[3];

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

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
  • ?

Keyboard switch part 1

Testing the first keyboard. It is the 8085-SDK hex matrix keyboard.

It is running on a Raspberry Pi Zero 2, without X server.
So the images are displayed using the framebuffer.
Also the touch data is read using evdev and the raw devices.


  • HID part
  • Add a rotary button for the selection of the different Keyboard Layouts
  • Improvement keyboard matrix calculation to find out which key is being pressed.
  • Code to control AT/PS2 computers directly using GPIO pins
  • Add a controller to use Raw controlling of matrix pins ( 6502 C64 hardware for example )

Bash test and configuring the OS for testing.

cat <<EOF >> /boot/config.txt
hdmi_timings=400 0 100 10 140 1280 10 20 20 2 0 0 0 60 0 43000000 3

# Image testing
apt-get install fbi
sudo fbi -d /dev/fb0 -T 1 8085.png  -a --noverbose

apt-get install python3-evdev python3-uinput evtest

First simple python test

import select
from math import floor
import sys
slot = 0


for path in evdev.list_devices():
    device = evdev.InputDevice(path)
    if evdev.ecodes.EV_ABS in device.capabilities():
    sys.stderr.write('Failed to find the touchscreen.\n')

while True:
    r, w, x =[device.fd], [], [])

    id_ = -1
    x = y = 0

    for event in

        if event.code == event.value == 0:
           if id_ != -1:
                yy = floor(( x - 600 ) / 700)
                xx = floor(( y - 1377 ) / 226)
                if yy < 4 and yy >=0 and xx < 6 and xx >= 00:
                     if slot == 1:

        elif event.code == ABS_MT_TRACKING_ID:
            id_ = event.value
        elif event.code == ABS_MT_SLOT:
            slot = event.value
        elif event.code == ABS_MT_POSITION_X:
            x = event.value
        elif event.code == ABS_MT_POSITION_Y:
            y = event.value

I came up with a simple matrix calculation

Pressing the 4 corner keys gave me x and y.
I took averages for min and max reading.
I don’t need pixel-perfect reading, and I noticed values between 960 and 3080 vertically.
We want 960 – 3080 into 4 blocks, but the middle should start @ 960.

So 3080/3 = about 700
700 / 2 = 350
block 1 starts 350 sooner than 960 is ~ 600
Upper key y coords = 600-> + 700
Next is 1300 -> + 700
converting to whole numbers using floor gives me:
floor(( y – 600 ) / 700)
NOTE: My x and y are rotated

Example using coordinates
1600, 1600
floor(( 1600 – 600 ) / 700) = floor(1,4…) = 1st row
(from row 0,1,2,3)

C64 Assembly, KiCad PCB design, and Keyboard Layout switcher

I’ve been busy programming Python and NodeRed for a client.
But these are the things I’ve done in the last days.

C64 Assembly:
Breaking borders, using sprites and multicolor font intro.

It does not look impressive, but I’ve learned a lot.
Found a new way (for me) to open borders and change border colours on predefined raster lines.
Sources will be posted.

KiCad tutorial, posted on YT also because I could not find many resources about the subject online. Maybe it’s helpful

Video editing using Kdenlive.

Edit: Even faster, use Netlabels, no need to join pins.
Press L (uppercase) select pin 1, name 1.
Press and hold insert until all pins named.
Copy paste socket 5 times and goto your PCB tab.

This movie is about creating a backplane for a 6502 SBC I’m building.
It is real-time and below 4 minutes.

Multi Keyboard

My small multitouch screen came in.
This is for my previously mentioned multi-computer case.

It is going to show multiple keyboard layouts for different systems.
(See previous posts about this)

Waveshare display, Raspberry Zero as HID device, using USB and pin emulated keyboards. (c64 matrix, AT (DIN) keyboard, ps2 keyboard)

Some example screens

Petscii C64
Another C64

I’m also going to make a layout like the keyboards on my 8085

Listening to Paganini

Niccolò (or Nicolò) Paganini.
October 1782 – 27 May 1840) was an Italian violinist and composer. He was the most celebrated violin virtuoso of his time, and left his mark as one of the pillars of modern violin technique. His 24 Caprices for Solo Violin Op. 1 are among the best known of his compositions and have served as an inspiration for many prominent composers.

I love listening to Paganini. The man was a beast.
Extreme technical, a pop star in his time.
But also because of that, he was seen as a demon.

Like the master bagpipers Stuart Liddell or the late Gordon Duncan.

Listening to Paganini’s caprices was wonderful.

A capriccio or caprice (sometimes plural: caprices, capri or, in Italian, capricci), is a piece of music, usually fairly free in form and of a lively character. The typical capriccio is one that is fast, intense, and often virtuosic in nature.

My top selection :


Why difficult?

Because of the advanced techniques, including parallel octaves, rapid interval shifts, extremely fast scales and arpeggios (including minor scales), left-hand pizzicato, high positions, and fast string crossings. Additionally, it features many double stops, such as thirds and tenths.

An arpeggio is a type of broken chord in which the notes that compose a chord are individually sounded in a progressive rising or descending order.

Pizzicato is a playing technique that involves plucking the strings of a string instrument.

Double stops are a fundamental technique in which two notes are played simultaneously on a stringed instrument. In the context of the violin, this entails using the bow to sound two adjacent strings at the same time.

On another note:

I finally got hold of the last missing Audio CD from Martyn Bennett!
I was looking for this for ages!

64×64 Etch a Sketch

In the past I made a Etch a Sketch with my lasercutter.

Using two rotary encoders and the 64×64 matrix display I recently bought, I made a drawing thingy.
Like a Etch a Sketch.

Some Circuit Python code.
Now I have to fix an out of memory issue using below.
And make a colour selection button??? 🙂

import time
import board
import displayio
import math
import vectorio
import rgbmatrix
import framebufferio
import array
import bitmaptools

import rotaryio
import board

encoder1 = rotaryio.IncrementalEncoder(board.GP27, board.GP26)
encoder2 = rotaryio.IncrementalEncoder(board.GP18, board.GP19)

last_position1 = 0
last_position2 = 0

# Release any existing displays

# --- Matrix Properties ---

# --- Matrix setup ---
matrix = rgbmatrix.RGBMatrix(
    width=64, bit_depth=2, height=64,
    rgb_pins=[board.GP0, board.GP1, board.GP2, board.GP3, board.GP4, board.GP5],
    addr_pins=[board.GP6, board.GP7, board.GP8, board.GP9, board.GP22],
    clock_pin=board.GP10, latch_pin=board.GP12, output_enable_pin=board.GP13)
colrs = 13
display = framebufferio.FramebufferDisplay(matrix, auto_refresh=True)
b1 = displayio.Bitmap(display.width, display.height, colrs )
palette = displayio.Palette(colrs )
palette[0] = 0x000000  # black
palette[1] = 0x964B00  # brown (light yellow) 
palette[2] = 0x00FFFF  # cyan
palette[3] = 0x850101  # deep red 
palette[4] = 0x7F00FF  # violet
palette[5] = 0xC46210  # orange
palette[6] = 0x3D9140  # Cobalt green  
palette[7] = 0x004225  # british racing green 
palette[8] = 0x8B008B  # dark magenta 
palette[9] = 0x1F75FE  # crayola  blue
palette[10] =0x00308F  # air force blue US air force    
palette[11] =0xBF00FF  # electric purple 
palette[12] =0x08E8DE  # turquoise
g1 = displayio.Group(scale=1)
display.root_group = g1 

bmp = displayio.Bitmap(64,64, 2)

tilegrid = displayio.TileGrid(bitmap=bmp, pixel_shader=palette)
display.auto_refresh = True

tilegrid = displayio.TileGrid(bitmap=bmp, pixel_shader=palette)
while True:
        position1 = encoder1.position
        if last_position1 is None or position1 != last_position1:

            if position1 > last_position1:
                position1 = position1 + 1
            if position1 < last_position1:
                position1 = position1 - 1
            if position1 < 0:
                position1 = 0
            last_position1 = position1
        position2 = encoder2.position
        if last_position2 is None or position2 != last_position2:
            if position2 > last_position2:
                position2 = position2 + 1
            if position2 > last_position2:
                position2 = position2 - 1
            if position2 < 0:
                position2 = 0
            last_position2 = position2

        tilegrid = displayio.TileGrid(bitmap=bmp, pixel_shader=palette)
        display.auto_refresh = True

Lilygo PC, 68000 progress and C64 hacks

Made a micro PC using Fabgl library and a ESP32 LilyGo Vga

More info about this device

68000 Progress

My address decoder seems to work (using an ATF22v10C) See previous posts.

Also new Rom and Ram chips. These are 8 bits, but the 68000’s data bus we need two (Odd and Even Addresses)

C64 Hacks

I made a proof of concept for a Rom switcher.
8 Different Roms can be selected using the dip switches.
(Dipswitches are being replaces bij something smarter in the future, like an Arduino Nano (like Adrian Black’s solution)

My other C64 stopped working, I need to make my PLA replacement.
But beside the PLA not working, I noticed the glass fuse was blown.
I didn’t have a large fuse (32mm) but a small one.
(Fast 1.6A and 230V)
So some fancy soldering and fixed.

"If something is worth doing, it's worth overdoing."