mirror of
https://github.com/EranMorkon/AMTS.git
synced 2023-12-28 16:48:38 +00:00
52 lines
3.5 KiB
Plaintext
52 lines
3.5 KiB
Plaintext
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1 ;******************************************************************************
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2 ;* Z80 Assembler program *
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3 ;* Josef Reisinger *
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4 ;* josef.reisinger@htl-hl.ac.at *
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5 ;* 26/04/2015 *
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6 ;******************************************************************************
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7
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8 ; ---------------------------- PIO 82C55 I/O ---------------------------------
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9 0080 PIO_A: EQU $80 ; (INPUT)
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10 0081 PIO_B: EQU $81 ; (OUTPUT) OUT TO LEDS
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11 0082 PIO_C: EQU $82 ; (INPUT) IN from DIP SWITCHES
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12 0083 PIO_CON: EQU $83 ; CONTROL BYTE PIO 82C55
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13
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14 ; --------------------------- CTC Z80 Timer Counter --------------------------
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15 0000 CTC0 EQU $00 ; Channel 0
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16 0001 CTC1 EQU $01 ; Channel 1
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17 0002 CTC2 EQU $02 ; Channel 2
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18 0003 CTC3 EQU $03 ; Channel 3
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19
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20 ; -------------------------- SIO (USART) ----------------------------------------
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21 0040 SIO_A_D: EQU $40 ; Channel A Data Register
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22 0041 SIO_B_D: EQU $41 ; Channel B Data Register
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23 0042 SIO_A_C: EQU $42 ; Channel A Control Register
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24 0043 SIO_B_C: EQU $43 ; Channel B Control Register
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25
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26
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27 ;-------------------------- CONSTANTS ----------------------------------------
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28 FFFF RAMTOP: EQU $FFFF ; 32Kb RAM 8000H-FFFFH
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29
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30 ;******************************************************************************
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31 ;* START AFTER RESET, *
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32 ;* Function....: ready system and restart *
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33 ;******************************************************************************
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34 0000 ORG $0000
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35 0000 F3 DI ; Disable interrupt
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36 0001 31 FF FF LD SP,RAMTOP ; Set stack pointer to top off ram
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37 0004 3E 15 LD A,$15 ; Configure CTC Channel 0:No Interrupt, Timer Mode, No Prescaler,
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38 0006 D3 00 OUT (CTC0),A ; trigger on positive edge, next word = time constant, Channel continuous result operation
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39 0008 3E BA LD A,186 ; Write Time constant 186*560ns= 104µs
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40 000A D3 00 OUT (CTC0),A
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41 000C DB 00 AGAIN: IN A,(CTC0) ; Read actual status of CTC Channel 0
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42 000E C3 0C 00 JP AGAIN ; Endlos
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43
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Symbol table:
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AGAIN 000C CTC0 0000 CTC1 0001 CTC2 0002
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CTC3 0003 PIO_A 0080 PIO_B 0081 PIO_C 0082
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PIO_CON 0083 RAMTOP FFFF SIO_A_C 0042 SIO_A_D 0040
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SIO_B_C 0043 SIO_B_D 0041
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14 symbols.
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