Last Updated or created 2022-09-14
New address decoder in place!
Connected RAM/ROM/SID/VIA1/VIA2 and ACIA
|VIA1||6000-60xx (Hex key matrix)|
|VIA2||5000-50xx (led test at the moment)|
To plan: Bigger maxtrix keyboard and other displays
Got a serial connection working between the 6502 and my linux machine!
At the moment when a reset occurs , hello is being printed.
Text typed in the minicom terminal, is echo-ed back and displayed on the LCD display.
Things learned: Do not trust internet schematics blindly!
The crystal used for the ACIA (pin 6/7 1.8432Mhz needs a 1M ohm resistor parallel over the crystal, and a 30nF capacitor from pin 7 to GND
When using a terminal emulator, and using 3 wires. Disable hardware handshake.
What didn´t work as planned:
New amplifier schematic for the SID. There is too much noise.
Bought a dual power supply (5V and 12V). But this one has a lot of signal noise on the SID part and even my battlestation speakers!
LED test 2nd via
PORTB = $5000 ; VIA PORTB PORTA = $5001 ; VIA PORTA DDRB = $5002 ; Data direction register DDRA = $5003 ; Data direction register LED = %10000000 .org $8000 reset: lda #%11100000 ; Set top 3 pins on port A to output sta DDRA lda LED sta PORTA loop: ; done loop until doomsday jmp loop irq: nmi: .org $fffa .word nmi .word reset .word irq
ACIA_RX = $6800 ACIA_TX = $6800 ACIA_STATUS = $6801 ACIA_COMMAND = $6802 ACIA_CONTROL = $6803 lda #$00 sta ACIA_STATUS lda #$0b sta ACIA_COMMAND lda #$1f sta ACIA_CONTROL