mirror of
https://github.com/EranMorkon/AMTS.git
synced 2023-12-28 16:48:38 +00:00
110 lines
6.8 KiB
Plaintext
110 lines
6.8 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 8000 COUNTER: EQU $8000 ; RAM Counter
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30
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31
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32 ;******************************************************************************
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33 ;* RESET HANDLER *
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34 ;* Function: Initialize system and start Main Program *
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35 ;******************************************************************************
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36 0000 ORG $0000
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37 0000 F3 DI ; Disable interrupt
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38 0001 31 FF FF LD SP,RAMTOP ; Set stack pointer
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39 0004 C3 00 01 JP MAIN ; jump to Main program
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40
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41
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42 ;*******************************************************************
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43 ;* MAIN PROGRAM *
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44 ;*******************************************************************
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45 0100 ORG $0100
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46 0100 21 00 80 MAIN: LD HL,COUNTER ; Reset RAM Counter
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47 0103 3E 00 LD A,$00
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48 0105 77 LD (HL),A
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49
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50 ; ------------------ Initialize PIO ----------------
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51 0106 3E 99 LD A,$99 ; Initialize 8255: PA0-PA7=IN (DIP SWITCHES), PB0-PB7=OUT (LEDS),
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52 0108 D3 83 OUT (PIO_CON),A ; PC0-PC7=IN, Mode 0 Selection
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53
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54 ;------------------ Configure CTC -----------------------
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55 010A 3E A5 LD A,$A5 ; Configure CTC Channel 0: Interrupt, Timer Mode, Prescaler = 256,
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56 010C D3 00 OUT (CTC0),A ; trigger on positive edge, next word = time constant, Channel continuous result operation
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57 010E 3E FF LD A,$FF ; Write Time constant 255*256*552ns= 36,03ms
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58 0110 D3 00 OUT (CTC0),A
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59 0112 3E A8 LD A,$A8 ; Loading Interrupt Vector register
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60 0114 D3 00 OUT (CTC0),A ; trigger on positive edge, next word = time constant, Channel continuous result operation
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61
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62 ;---------------------- Configure Interrupt -----------------
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63 0116 3E 01 LD A,$01 ; Loading Interrupt Register
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64 0118 ED 47 LD I,A
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65 011A ED 5E IM 2 ; Interrupt Mode 2
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66 011C FB EI ; Enable Interrupt
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67
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68 ;--------------------- Main Program --------------------------
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69 011D C3 1D 01 AGAIN: JP AGAIN ; Endless
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70
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71
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72
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73 ;******************************************************************************
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74 ;* INTERRUPT SERVICE ROUTINE *
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75 ;* CTC Channel 0 *
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76 ;******************************************************************************
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77 01A8 ORG $01A8
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78 01A8 AA 01 DEFW _INT_CTC
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79 01AA F5 _INT_CTC: PUSH AF
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80 01AB E5 PUSH HL
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81 01AC 21 00 80 LD HL,COUNTER
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82 01AF 7E LD A,(HL) ; Read Counter
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83 01B0 3C INC A ; Increment Counter
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84 01B1 FE 07 CP $07 ; 252,21ms reached?
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85 01B3 C2 BD 01 JP NZ,_END_INT
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86 01B6 3E 00 LD A,$00 ; Reset Counter
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87 01B8 DB 81 IN A,(PIO_B) ; Toggle LED's with 2Hz
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88 01BA 2F CPL
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89 01BB D3 81 OUT (PIO_B),A ;
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90 01BD 77 _END_INT: LD (HL),A ; Store Counter
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91 01BE E1 POP HL
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92 01BF F1 POP AF
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93 01C0 FB EI ; Entry Point of Interrupt Service Routine
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94 01C1 ED 4D RETI
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95
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96
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97
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98
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99
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100
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Symbol table:
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AGAIN 011D COUNTER 8000 CTC0 0000 CTC1 0001
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CTC2 0002 CTC3 0003 MAIN 0100 PIO_A 0080
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PIO_B 0081 PIO_C 0082 PIO_CON 0083 RAMTOP FFFF
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SIO_A_C 0042 SIO_A_D 0040 SIO_B_C 0043 SIO_B_D 0041
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_END_INT 01BD _INT_CTC 01AA
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18 symbols.
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