mirror of
https://github.com/EranMorkon/AMTS.git
synced 2023-12-28 16:48:38 +00:00
91 lines
4.5 KiB
ArmAsm
91 lines
4.5 KiB
ArmAsm
|
;******************************************************************************
|
||
|
|
;* Z80 Assemblerprogramm *
|
||
|
|
;* Josef Reisinger *
|
||
|
|
;* josef.reisinger@htl-hl.ac.at *
|
||
|
|
;* 26/04/2015 *
|
||
|
|
;******************************************************************************
|
||
|
|
|
||
|
|
; ---------------------------- PIO 82C55 I/O ---------------------------------
|
||
|
|
PIO_A: EQU $80 ; (INPUT)
|
||
|
|
PIO_B: EQU $81 ; (OUTPUT) OUT TO LEDS
|
||
|
|
PIO_C: EQU $82 ; (INPUT) IN from DIP SWITCHES
|
||
|
|
PIO_CON: EQU $83 ; CONTROL BYTE PIO 82C55
|
||
|
|
|
||
|
|
; --------------------------- CTC Z80 Timer Counter --------------------------
|
||
|
|
CTC0 EQU $00 ; Channel 0
|
||
|
|
CTC1 EQU $01 ; Channel 1
|
||
|
|
CTC2 EQU $02 ; Channel 2
|
||
|
|
CTC3 EQU $03 ; Channel 3
|
||
|
|
|
||
|
|
; -------------------------- SIO (USART) ----------------------------------------
|
||
|
|
SIO_A_D: EQU $40 ; Channel A Data Register
|
||
|
|
SIO_B_D: EQU $41 ; Channel B Data Register
|
||
|
|
SIO_A_C: EQU $42 ; Channel A Control Register
|
||
|
|
SIO_B_C: EQU $43 ; Channel B Control Register
|
||
|
|
|
||
|
|
;-------------------------- CONSTANTS ----------------------------------------
|
||
|
|
RAMTOP: EQU $FFFF ; 32Kb RAM 8000H-FFFFH
|
||
|
|
COUNTER: EQU $8000 ; RAM Counter
|
||
|
|
|
||
|
|
;******************************************************************************
|
||
|
|
;* RESET HANDLER *
|
||
|
|
;* Function: Initalize system and start Main Programm *
|
||
|
|
;******************************************************************************
|
||
|
|
ORG $0000
|
||
|
|
DI ; Disable interrupt
|
||
|
|
LD SP,RAMTOP ; Set stack pointer
|
||
|
|
JP MAIN ; jump to Main program
|
||
|
|
|
||
|
|
;*******************************************************************
|
||
|
|
;* MAIN PROGRAM *
|
||
|
|
;*******************************************************************
|
||
|
|
ORG $0100
|
||
|
|
MAIN: LD HL,COUNTER ; Reset RAM Counter
|
||
|
|
LD A,$00
|
||
|
|
LD (HL),A
|
||
|
|
|
||
|
|
; ------------------ Initialize PIO ----------------
|
||
|
|
LD A,$99 ; Initialize 8255: PA0-PA7=IN (DIP SWITCHES), PB0-PB7=OUT (LEDS),
|
||
|
|
OUT (PIO_CON),A ; PC0-PC7=IN, Mode 0 Selektion
|
||
|
|
|
||
|
|
;------------------ Configure CTC -----------------------
|
||
|
|
LD A,$A5 ; Configure CTC Channel 0:Interrupt, Timer Mode, Prescaler = 256,
|
||
|
|
OUT (CTC0),A ; trigger on positive edge, next word = time constant, Channel continuous result operation
|
||
|
|
LD A,$FF ; Write Time constant 255*256*552ns= 36,03ms
|
||
|
|
OUT (CTC0),A
|
||
|
|
LD A,$A8 ; Loading Interrupt Vector register
|
||
|
|
OUT (CTC0),A ; trigger on positive edge, next word = time constant, Channel continuous result operation
|
||
|
|
|
||
|
|
;---------------------- Configure Interrupt -----------------
|
||
|
|
LD A,$01 ; Loading Interrupt Register
|
||
|
|
LD I,A
|
||
|
|
IM 2 ; Interrupt Mode 2
|
||
|
|
EI ; Enable Interrupt
|
||
|
|
|
||
|
|
;--------------------- Main Program --------------------------
|
||
|
|
AGAIN: JP AGAIN ; Endlos
|
||
|
|
|
||
|
|
|
||
|
|
;******************************************************************************
|
||
|
|
;* INTERRUPT SERVICE ROUTINE *
|
||
|
|
;* CTC Channel 0 *
|
||
|
|
;******************************************************************************
|
||
|
|
ORG $01A8
|
||
|
|
DEFW _INT_CTC
|
||
|
|
_INT_CTC: PUSH AF
|
||
|
|
PUSH HL
|
||
|
|
LD HL,COUNTER
|
||
|
|
LD A,(HL) ; Read Counter
|
||
|
|
INC A ; Increment Counter
|
||
|
|
CP $07 ; 252,21ms reached?
|
||
|
|
JP NZ,_END_INT
|
||
|
|
LD A,$00 ; Reset Counter
|
||
|
|
IN A,(PIO_B) ; Toggle LED's with 2Hz
|
||
|
|
CPL
|
||
|
|
OUT (PIO_B),A ;
|
||
|
|
_END_INT: LD (HL),A ; Store Counter
|
||
|
|
POP HL
|
||
|
|
POP AF
|
||
|
|
EI ; Entry Point of Interrupt Service Routine
|
||
|
|
RETI
|