mirror of
https://github.com/EranMorkon/AMTS.git
synced 2023-12-28 16:48:38 +00:00
43 lines
2.4 KiB
ArmAsm
43 lines
2.4 KiB
ArmAsm
|
;******************************************************************************
|
||
|
|
;* Z80 Assembler program *
|
||
|
|
;* 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
|
||
|
|
|
||
|
|
;******************************************************************************
|
||
|
|
;* START AFTER RESET, *
|
||
|
|
;* Function....: ready system and restart *
|
||
|
|
;******************************************************************************
|
||
|
|
ORG $0000
|
||
|
|
DI ; Disable interrupt
|
||
|
|
LD SP,RAMTOP ; Set stack pointer to top off ram
|
||
|
|
LD A,$15 ; Configure CTC Channel 0:No Interrupt, Timer Mode, No Prescaler,
|
||
|
|
OUT (CTC0),A ; trigger on positive edge, next word = time constant, Channel continuous result operation
|
||
|
|
LD A,186 ; Write Time constant 186*560ns= 104µs
|
||
|
|
OUT (CTC0),A
|
||
|
|
AGAIN: IN A,(CTC0) ; Read actual status of CTC Channel 0
|
||
|
|
JP AGAIN ; Endlos
|