mirror of
https://github.com/EranMorkon/AMTS.git
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36 lines
1.7 KiB
ArmAsm
36 lines
1.7 KiB
ArmAsm
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;******************************************************************************
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;* Z80 Assembler program *
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;* Josef Reisinger *
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;* josef.reisinger@htl-hl.ac.at *
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;* 26/04/2015 *
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;******************************************************************************
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;************************* HARDWARE IO ADR ************************************
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; PIO 82C55 I/O
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PIO1A: EQU $80 ; INPUT - DIP SWITCHES
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PIO1B: EQU $81 ; OUTPUT - LEDS
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PIO1C: EQU $82 ; (INPUT)
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PIO1CONT: EQU $83 ; CONTROL BYTE PIO 82C55
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;*************************** CONSTANTS ****************************************
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RAMTOP: EQU $FFFF ; 32Kb RAM 8000H-FFFFH
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;******************************************************************************
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;* START AFTER RESET, *
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;* Function....: ready system and restart *
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;******************************************************************************
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ORG $0000
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;DI ; Disable interrupt
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;LD SP,RAMTOP ; Set stack pointer to top off ram
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LD A,$99 ; PA0-PA7=IN (DIP SWITCHES), PB0-PB7=OUT (LEDS),
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; PC0-PC7=IN, Mode 0 Selection
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OUT (PIO1CONT),A
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IN A,(PIO1CONT)
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AGAIN:
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IN A,(PIO1A) ; Read actual status of Switches (PA0-PA7)
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OUT (PIO1B),A ; Output Status to LEDs (PB0-PB7)
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JP AGAIN ; Endlos
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