blondie7575
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| // Configure INT2 (interrupt 2, on line PB2) to be a rising | |
| // edge interrupt that we'll get from the CPU | |
| // See ATmega324PA datasheet p68 | |
| cbi EIMSK,INT2_BIT | |
| ldi accum,EICRA | |
| ori accum,_BV(ISC20) | _BV(ISC21) | |
| sts EICRA,accum | |
| cbi EIFR,INTF2 | |
| sbi EIMSK,INT2_BIT |
blondie7575
/ AVRInterruptHandler.as
Created
August 19, 2012 23:59
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| INT2_vect: | |
| // Get ourselves completely off the bus | |
| clr accum | |
| out PORTD,accum | |
| out DDRD,accum | |
| out DDRC,accum | |
| out DDRA,accum | |
| sbi PORTB,vramWrite |
blondie7575
/ gist:4247333
Created
December 9, 2012 22:44
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| // Plot a red pixel | |
| testRender1: | |
| // Take control of VRAM | |
| EnableVRAMWrite | |
| // Load a reasonable VRAM address | |
| ldi accum,0x58 | |
| out PORTC,accum | |
| ldi accum,0x1C |
blondie7575
/ gist:4247360
Created
December 9, 2012 22:55
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| # Makefile | |
| # | |
| # Parts of this are borrowed from http://electrons.psychogenic.com | |
| # | |
| DEVICE=atmega324pa | |
| CLOCK = 20000000UL | |
| PROGRAMMER = usbtiny | |
| FUSES = -U lfuse:w:0xe0:m -U hfuse:w:0xd9:m -U efuse:w:0xff:m |
blondie7575
/ gist:4247372
Created
December 9, 2012 22:58
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| define(EnableVRAMWrite, ` | |
| sbi PORTB,vramOE | |
| ldi accum,0xff | |
| out DDRD,accum | |
| ') | |
| define(DisableVRAMWrite, ` | |
| clr accum | |
| out DDRD,accum | |
| out PORTD,accum |
blondie7575
/ gist:4247619
Created
December 10, 2012 00:14
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| ldy #$ff | |
| OUTER: | |
| ldx $ff | |
| INNER: | |
| nop | |
| nop | |
| nop | |
| nop | |
| nop | |
| nop |
blondie7575
/ gist:4958367
Created
February 15, 2013 03:28
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| 0xAD,0xFF,0xEF, // LDA $EFFF : FE00 | |
| 0xC9,0xFF, // CMP #$FF | |
| 0xF0,0xF9, // BEQ $FE00 | |
| 0xAD,0xFF,0xEF, // LDA $EFFF : FE07 | |
| 0xC9,0xFF, // CMP #$FF | |
| 0xD0,0xF9, // BNE $FE07 | |
| 0xA9,0x04, // LDA #$04 | |
| 0x8D,0xFF,0xEF, // STA $EFFF | |
| 0xA9,0x01, // LDA #$01 |
blondie7575
/ gist:4958372
Created
February 15, 2013 03:29
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| 0xAD,0xFF,0xEF, // LDA $EFFF : FE00 | |
| 0xC9,0xFF, // CMP #$FF | |
| 0xF0,0xF9, // BEQ $FE00 | |
| 0xAD,0xFF,0xEF, // LDA $EFFF : FE07 | |
| 0xC9,0xFF, // CMP #$FF | |
| 0xD0,0xF9, // BNE $FE07 | |
| 0xA9,0x04, // LDA #$04 | |
| 0x8D,0xFF,0xEF, // STA $EFFF | |
| 0xA9,0x01, // LDA #$01 |
blondie7575
/ gist:4958409
Created
February 15, 2013 03:36
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| ///////////////// | |
| // CPU Interrupt Service Routine | |
| // | |
| INT2_vect: | |
| // Save registers | |
| push accum | |
| in accum,SREG | |
| push accum |
blondie7575
/ gist:4958420
Created
February 15, 2013 03:40
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| mainloop: | |
| // Wait for VBL to process commands | |
| sbrs VBL,0 | |
| rjmp mainloop | |
| // See if there's a command pending | |
| lds regS,CMDBUFFER_S | |
| lds regT,CMDBUFFER_E |
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