petrihakkinen

// Multiplexed PWM RGB Led Demo
// By Petri Hakkinen
// 24th November 2014
//
// Arduino Uno driving a single RGB led with only one resistor.
//
// Make the following connections:
// * Connect Arduino pins D2,D3,D3 to anodes of a RGB led.
// * Connect cathode of the RGB led to 330 ohm resistor.
// * Connect the other end of the resistor to ground.

petrihakkinen

const uint8_t rom[] = {
	0xa2, 0xff,			// ldx #$ff
	0xca,				// dex
	0xd0, 0xfd,			// bne $ff02 (relative address $fd = -3)
	0xe6, 0x10,			// inc $10
	0x4c, 0x00, 0xf0,	// jmp $f000
};

petrihakkinen

// stop CPU clock in high state
void stopClock() {
	// wait for clock to go low
	while((PIND & CPU_CLOCK) != 0) {}
	// wait for clock to go high
	// must check that WE is high, otherwise CPU may be writing to memory
	while((PIND & (CPU_CLOCK|SRAM_WE)) == 0) {}
	TCCR2B = 0;	// stop timer by setting prescaler to 0
	TCCR2A = 0;	// disable timer so that we can control PD7 manually
}

petrihakkinen

; phase 1: 6502 is bus master (8 cycles)
; prepare atmega for memory access by preloading address (address lines are still inputs so this will only affect internal pull up resistors)
out     PORTA, lo       ; load lo address 
out     PORTB, hi       ; load hi address
st      X+, data        ; store data received in previous phase 0
adiw    address, 1      ; increment address
nop
nop

; phase 0: atmega is bus master (8 cycles)

petrihakkinen

; halt CPU (20 cycles)
sts     TCCR2B, r0                          ; TCCR2B = 0
call    delay16                             ; wait a while so that the 6502 can finish whatever it was doing
cbi     _SFR_IO_ADDR(PORTD), BUS_ENABLE     ; disable bus

; ATmega can now do whatever dirty tricks it likes in the memory

; restart CPU (5 cycles)
sbi     _SFR_IO_ADDR(PORTD), BUS_ENABLE     ; enable bus
ldi     r24, 1

petrihakkinen

    ; copy 128 bytes, 6 cycles per byte (768 cycles)
.rept 128
    out     _SFR_IO_ADDR(PORTA), ZL             ; PORTA = lo
    addi    ZL, 1
    nop
    in      r24, _SFR_IO_ADDR(PINC)             ; r24 = data
    st      X+, r24
.endr

petrihakkinen

const uint8_t rom[] = {
    // clear screen
    // screen memory starts at $c000 and is 50*25 = 1600 bytes long
    // clear first 6*256 = 1536 bytes
    0xa9, 32,           // lda #32   'space'
    0xa2, 0,            // ldx #0
//clearloop:
    0x9d, 0x00, 0xc0,   // sta $c000,x
    0x9d, 0x00, 0xc1,   // sta $c100,x
    0x9d, 0x00, 0xc2,   // sta $c200,x

petrihakkinen

-- sublime text 3 autcomplete dialog width is hardcoded to 300 pixels
-- this lua script changes it to 600 pixels by modifying the sublime text executable
-- backup the original executable before running the patch!

local filename = "c:/program files/sublime text 3/sublime_text.exe"

local hex = function(t)
	local s = ""
	for i=1,#t do
		s = s..string.char(t[i])

petrihakkinen

		;*****************************************************************
		; negate accumulator
		;*****************************************************************

neg:		eor #$ff
		clc
		adc #1
		rts

		;*****************************************************************

petrihakkinen

;*****************************************************************
; ZX7 decompressor based on
; ZX7 data decompressor for Apple II
; by Peter Ferrie (peter.ferrie@gmail.com)
; with modifications by Juan J. Martinez (@reidrac)
; optimized by Petri Häkkinen
; This code is in the Public Domain
;*****************************************************************

zx7_src_lo	= $20	; should always contain 0