Detailed construction instructions can be found on the GitHub page.

Load and run the Arduino Mega 2560 with the following sketch:

https://github.com/lambdamikel/Busch-2090/blob/master/PGM-EEPROM-MEGA/PGM-EEPROM-MEGA.ino

This will store the Microtronic example programs PGM 7 to PGM C in EEPROM. The emulator will not initialize / start up properly without proper EEPROM contents.

Program the Arduino Mega 2560 with the main emulator sketch:

https://github.com/lambdamikel/Busch-2090/blob/master/busch2090-mega-v3/busch2090-mega-v3.ino

Set up the hardware - you can set it up any way you like, but I recommend using the laser-cut acrylic front panel. Its blue print can be found in the files section of the project.

Set up the hardware - the emulator main sketch shows the pin layout:

//
// SD+Ethernet Shield (optional) 
//

#if defined (SDCARD)
#define SDCARD_CHIP_SELECT 4

//
// software serial interface for Emic 2 TTS module (optional)
//

#if defined (SPEECH)
#define RX_SPEECH A8
#define TX_SPEECH 53
#endif

//
// momentary N.O. push buttons
//

#define RESET  47 // soft reset 

#define BACK   63
#define RIGHT  64
#define UP     65
#define DOWN   66
#define LEFT   67
#define CANCEL 68
#define ENTER  69

//
// Status LEDs
//

#define DOT_LED_1 55
#define DOT_LED_2 56
#define DOT_LED_3 57
#define DOT_LED_4 58

#define CLOCK_LED     39
#define CLOCK_1HZ_LED 41
#define CARRY_LED     43
#define ZERO_LED      45

//
// 1 Hz clock digital output
//

#define CLOCK_OUT 6

//
// DOT digital output
//

#define DOT_1 5
#define DOT_2 3
#define DOT_3 2  // we need pin 4 for SD card!
#define DOT_4 18 // PIN 1 didn't work for some reason

//
// DIN digital input
//

#define DIN_1 17
#define DIN_2 16
#define DIN_3 15
#define DIN_4 14

//
// telephone keypad buttons for DIN input
//

#define DIN_BUTTON_1 42 // telephone keypad # 
#define DIN_BUTTON_2 44 // telephone keypad 9 
#define DIN_BUTTON_3 46 // telephone keypad 6
#define DIN_BUTTON_4 48 // telephone keypad 3 

//
// remaining telephone keypad buttons
//

#define CCE  26 // telephone keypad *
#define RUN  28 // telephone keypad 7
#define BKP  30 // telephone keypad 4
#define NEXT 32 // telephone keypad 1
#define PGM  34 // telephone keypad 0 
#define HALT 36 // telephone keypad 8 
#define STEP 38 // telephone keypad 5
#define REG  40 // telephone keypad 2 

//
// CPU speed throttle potentiometer
//

#define CPU_THROTTLE_ANALOG_PIN A0
#define CPU_THROTTLE_DIVISOR 10   // potentiometer dependent 
#define CPU_MIN_THRESHOLD 8       // if smaller than this, CPU = max speed  
#define CPU_MAX_THRESHOLD 99      // if higher than this, CPU = min speed 
#define CPU_DELTA_DISP 5          // if analog value changes more than this, update CPU delay display 

//
// for initialization of random generator
//

#define RANDOM_ANALOG_PIN A5

//
// LCD panel pins
//

LiquidCrystal lcd(13, 12, 11, 7, 9, 8); // we need pin 10 for SD card

//
// 2 Adafruit 7Segment LED backpacks
// In order to have to LED backpacks, you need
// to change the address by soldering a bridge
// on one of them - mine are set to 0x70 and 0x71
// See Adafruit instructions for more detail
// Both are connected to the I2C bus of the Mega 2560 
// (SCL = pin 21, SDA = pin 20)
//

Adafruit_7segment dispRight = Adafruit_7segment(); 
Adafruit_7segment dispLeft  = Adafruit_7segment();

//
// HEX 4x4 matrix keypad
//

byte colPins[COLS] = {37, 35, 33, 31}; // columns
byte rowPins[ROWS] = {29, 27, 25, 23}; // rows

... more soon - I am working on the schematics using Fritzing.