mirror of
https://github.com/sergeyyarkov/attiny2313a_shift-register-example.git
synced 2026-10-11 02:08:50 +03:00
119 lines
3.1 KiB
NASM
119 lines
3.1 KiB
NASM
;
|
|
; Project name: shift-register-example
|
|
; Description: An example of using the single 74HC595 shift register with an AVR microcontroller
|
|
; Source code: https://github.com/sergeyyarkov/attiny2313a_shift-register-example
|
|
; Device: ATtiny2313A
|
|
; Device Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/doc8246.pdf
|
|
; Package: SOIC-20W_7.5x12.8mm_P1.27mm
|
|
; Assembler: AVR macro assembler 2.2.7
|
|
; Clock frequency: 8 MHz Internal with CKDIV8
|
|
; Fuses: lfuse: 0x64, hfuse: 0x9F, efuse: 0xFF, lock: 0xFF
|
|
;
|
|
; Written by Sergey Yarkov 28.01.2023
|
|
|
|
.INCLUDE "tn2313Adef.inc"
|
|
.LIST
|
|
|
|
.DEF TEMP_A = r16 ; Temp register A
|
|
.DEF TEMP_B = r17 ; Temp register B
|
|
.DEF DATA = r20 ; DATA to transmit
|
|
|
|
;========================================;
|
|
; LABELS ;
|
|
;========================================;
|
|
|
|
.EQU CLOCK_PIN = PB0 ; SH_CP on 74HC595
|
|
.EQU DATA_PIN = PB1 ; DS on 74HC595
|
|
.EQU LATCH_PIN = PB2 ; ST_CP on 74HC595
|
|
|
|
;========================================;
|
|
; CODE SEGMENT ;
|
|
;========================================;
|
|
|
|
.CSEG
|
|
.ORG 0x00
|
|
|
|
;========================================;
|
|
; VECTORS ;
|
|
;========================================;
|
|
|
|
rjmp RESET_vect ; Program start at RESET vector
|
|
|
|
RESET_vect:
|
|
;========================================;
|
|
; INITIALIZE STACK POINTER ;
|
|
;========================================;
|
|
|
|
ldi TEMP_A, low(RAMEND)
|
|
out SPL, TEMP_A
|
|
|
|
MCU_INIT:
|
|
rcall INIT_PORTS
|
|
ldi DATA, 0b00000001
|
|
rjmp LOOP
|
|
|
|
;========================================;
|
|
; MAIN PROGRAM LOOP ;
|
|
;========================================;
|
|
|
|
LOOP:
|
|
rcall TRANSMIT_595
|
|
rol DATA
|
|
rcall DELAY
|
|
rjmp LOOP
|
|
|
|
INIT_PORTS:
|
|
ldi TEMP_A, (1<<CLOCK_PIN) | (1<<LATCH_PIN) | (1<<DATA_PIN)
|
|
out DDRB, TEMP_A
|
|
ret
|
|
|
|
;========================================;
|
|
; SEND BYTE TO 74HC595 ;
|
|
;========================================;
|
|
|
|
TRANSMIT_595:
|
|
in r21, SREG
|
|
mov r19, DATA
|
|
ldi TEMP_B, 8
|
|
_TRANSMIT_595_LOOP:
|
|
;
|
|
; Shift a bit into the Carry flag and check if it is set to 1 or 0.
|
|
lsl r19
|
|
brcc _TRANSMIT_595_SEND_LOW
|
|
brcs _TRANSMIT_595_SEND_HIGH
|
|
|
|
_TRANSMIT_595_SEND_HIGH:
|
|
sbi PORTB, DATA_PIN
|
|
rjmp _TRANSMIT_595_COMMIT
|
|
|
|
_TRANSMIT_595_SEND_LOW:
|
|
cbi PORTB, DATA_PIN
|
|
|
|
_TRANSMIT_595_COMMIT:
|
|
cbi PORTB, CLOCK_PIN
|
|
sbi PORTB, CLOCK_PIN
|
|
dec TEMP_B
|
|
brne _TRANSMIT_595_LOOP
|
|
|
|
;
|
|
; Copy data from shift register to storage register
|
|
sbi PORTB, LATCH_PIN
|
|
cbi PORTB, LATCH_PIN
|
|
out SREG, r21
|
|
ret
|
|
|
|
DELAY:
|
|
push TEMP_A
|
|
ldi TEMP_A, 70
|
|
_DELAY_1:
|
|
ldi TEMP_B, 255
|
|
_DELAY_2:
|
|
dec TEMP_B
|
|
nop
|
|
nop
|
|
nop
|
|
brne _DELAY_2
|
|
dec TEMP_A
|
|
brne _DELAY_1
|
|
pop TEMP_A
|
|
ret |