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tags: MPLAB Assembly PIC18F Breadboard LED PICKIT4

MPLAB - Assignment 6

PPT, Video, Hackmd
Goal
1. How to use Assembly control port on PIC18F4520
2. How to control connect picket 4 to computer
3. How to use jump wires on breadboard

Simple Tutorial

I/O ports of PIC18F4520

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Components

  1. breadboard
  2. pickit3 or pickit4
  3. PIC18F4520 transistor
  4. computer
  5. jump wires : many
  6. resistor : many
  7. led : 5
  8. button : 1

Connect

here is a example for test to MPLAB

  1. just copy this code 
    
























































    ​​​​LIST p=18f4520
​​​​#include<p18f4520.inc>
​CONFIG OSC = INTIO67 ; 1 MHZ
​CONFIG WDT = OFF
​CONFIG LVP = OFF
​
​L1	EQU 0x14
​L2	EQU 0x15
​org 0x00
​
​​​​; Total 2 + (2 + 7 * num1 + 2) * num2 cycles = C
​​​​; num1 = 200, num2 = 180, C = 252360
​​​​; Total delay ~= C/1M = 0.25s
​​​​DELAY macro num1, num2 
​​​​    local LOOP1 
​​​​    local LOOP2
​​​​    MOVLW num2
​​​​    MOVWF L2
​​​​    LOOP2:
​​​​    MOVLW num1
​​​​    MOVWF L1
​​​​    LOOP1:
​​​​    NOP
​​​​    NOP
​​​​    NOP
​​​​    NOP
​​​​    NOP
​​​​    NOP
​​​​    DECFSZ L1, 1
​​​​    BRA LOOP1
​​​​    DECFSZ L2, 1
​​​​    BRA LOOP2
​​​​endm


​​​​start:
​​​​int:
​​​​; let pin can receive digital signal 
​​​​MOVLW 0x0f
​​​​MOVWF ADCON1
​​​​CLRF PORTB
​​​​BSF TRISB, 0
​​​​CLRF LATA
​​​​BCF TRISA, 0

​​​​; ckeck button
​​​​check_process:
​​​​   BTFSC PORTB, 0
​​​​   BRA check_process
​​​​   BRA lightup


​​​​lightup:
​​​​    BTG LATA, 0
​​​​    DELAY d'200', d'180' ;delay 0.25s
​​​​    BRA check_process
​​​​end
  2. click Debug project
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  3. Warnning!
    • If you don't have this warnning, congradulation, just skip this point
    • If you have this problem, don't worry, The system just trying to tell you to be carefully sure that the transistor your use should be PIC18F4520. Thererfore, just click OK
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Circuit

  • all
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  • Remember that led should be insert in breadboard by this direction
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  • Insert the resistor into the board with one end in the same horizontal row as the LED’s cathode (short) leg and the other a few rows down. The resistor is not polarized so it does not matter which direction you insert it.
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Run

Everytime press button, the led will light or turn off. If you are successful, go down and have chanllenge of other examples!

Basic Example

Description

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Code











































































    LIST p=18f4520
    #include<p18f4520.inc>
	CONFIG OSC = INTIO67 ; 1 MHZ
	CONFIG WDT = OFF
	CONFIG LVP = OFF
	
	L1	EQU 0x14
	L2	EQU 0x15
	
	count EQU 0x01
	
	org 0x00
	
	
; Total 2 + (2 + 7 * num1 + 2) * num2 cycles = C
; num1 = 200, num2 = 180, C = 252360
; Total delay ~= C/1M = 0.25s
DELAY macro num1, num2 
    local LOOP1 
    local LOOP2
    MOVLW num2
    MOVWF L2
    LOOP2:
	MOVLW num1
	MOVWF L1
    LOOP1:
	NOP
	NOP
	NOP
	NOP
	NOP
	NOP
	DECFSZ L1, 1
	BRA LOOP1
	DECFSZ L2, 1
	BRA LOOP2
endm
	
	
initial:    
    MOVLW 0x01
    MOVWF count
    ; let pin can receive digital signal     
    MOVLW 0x0f
    MOVWF ADCON1
    CLRF PORTB
    BSF TRISB, 0
    CLRF LATA     ; output value
    BCF TRISA, 0 ; tell if its output(0) or input(1) 
    BCF TRISA, 1 ; tell if its output(0) or input(1) 
    BCF TRISA, 2 ; tell if its output(0) or input(1) 
    BCF TRISA, 3 ; tell if its output(0) or input(1) 
	
; ckeck button
check_process:
   BTFSC PORTB, 0    ; Bit Test f, Skip if clear
   BRA check_process ; not press
   BRA lightup       ; if press

;light up oled
lightup:
    MOVLW 0x0f
    CPFSEQ LATA
    BRA light   
    CLRF LATA
    BRA end_
    light: 
	RLCF LATA
	MOVF count,w
	IORWF LATA
	DELAY d'200', d'180' ;delay 0.25s
	BRA check_process  
end_:
end

Circuit

  • Button : Connect a push-button at RB0 port with pull-up or pull-down resistor.

  • LED : Connect four LEDs at RA0 ~ RA3 port. Press the button to change the blinking pattern of LEDs, as in the figure below.

  • Remember that every oled usually used in tandem with a resistance to protect led from too large voltage and prevent floating state(Use pull-down resistor)


  • Prevent floating state : Use pull-up resistor

Result

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demo

Advanced Example

Description

Code

  • just add delay between state5 and another press event

  • full code

    










































































    ​​​​LIST p=18f4520
​​​​#include<p18f4520.inc>
​CONFIG OSC = INTIO67 ; 1 MHZ
​CONFIG WDT = OFF
​CONFIG LVP = OFF
​
​L1	EQU 0x14
​L2	EQU 0x15
​
​count EQU 0x01
​
​org 0x00
​
​
​​​​; Total 2 + (2 + 7 * num1 + 2) * num2 cycles = C
​​​​; num1 = 200, num2 = 180, C = 252360
​​​​; Total delay ~= C/1M = 0.25s
​​​​DELAY macro num1, num2 
​​​​    local LOOP1 
​​​​    local LOOP2
​​​​    MOVLW num2
​​​​    MOVWF L2
​​​​    LOOP2:
​​​​    MOVLW num1
​​​​    MOVWF L1
​​​​    LOOP1:
​​​​    NOP
​​​​    NOP
​​​​    NOP
​​​​    NOP
​​​​    NOP
​​​​    NOP
​​​​    DECFSZ L1, 1
​​​​    BRA LOOP1
​​​​    DECFSZ L2, 1
​​​​    BRA LOOP2
​​​​endm


​​​​initial:    
​​​​    MOVLW 0x01
​​​​    MOVWF count
​​​​    ; let pin can receive digital signal     
​​​​    MOVLW 0x0f
​​​​    MOVWF ADCON1
​​​​    CLRF PORTB
​​​​    BSF TRISB, 0
​​​​    CLRF LATA     ; output value
​​​​    BCF TRISA, 0 ; tell if its output(0) or input(1) 
​​​​    BCF TRISA, 1 ; tell if its output(0) or input(1) 
​​​​    BCF TRISA, 2 ; tell if its output(0) or input(1) 
​​​​    BCF TRISA, 3 ; tell if its output(0) or input(1) 

​​​​; ckeck button
​​​​check_process:
​​​​   BTFSC PORTB, 0    ; Bit Test f, Skip if clear
​​​​   BRA check_process ; not press
​​​​   BRA lightup       ; if press

​​​​;light up oled
​​​​lightup:
​​​​    MOVLW 0x0f
​​​​    CPFSEQ LATA
​​​​    BRA light   
​​​​    CLRF LATA
​​​​    DELAY d'200', d'180' ;delay 0.25s
​​​​    BRA check_process
​​​​    light: 
​​​​    RLCF LATA
​​​​    MOVF count,w
​​​​    IORWF LATA
​​​​    DELAY d'200', d'180' ;delay 0.25s
​​​​    BRA check_process  

​​​​end

Bonus Example

Description

Code






























































































































LIST p=18f4520
    #include<p18f4520.inc>
	CONFIG OSC = INTIO67 ; 1 MHZ
	CONFIG WDT = OFF
	CONFIG LVP = OFF
	
	R1	EQU 0x14
	R2	EQU 0x15
	R3      EQU 0x16
      
	count EQU 0x00
	state EQU 0x01
	state_count EQU 0x02
	
	org 0x00
	
delay macro num
    local L_1
    local L_2
    local L_3
    MOVLW num
    MOVWF R3
    
    L_1:	; MAIN loop in the subroutine to generate a delay of R3 50x msecs
	MOVLW D'50'
	MOVWF R2	
    L_2:	; outer loop generates a delay of 50 msecs
	MOVLW D'199'
	MOVWF R1
    L_3:	; inner loop generates a delay of 1 msecs
	NOP
	NOP
	DECF R1
	BNZ L_3
	DECF R2
	BNZ L_2	
	DECF R3
	BNZ L_1
	
    endm
add_state macro s
    INCF s
    MOVLW 0x04
    CPFSLT s
    CLRF s
        
    endm
check_light macro s
    local s0
    local s1
    local s2
    local s3
    local end_
    MOVLW 0x03
    MOVWF LATA
    MOVLW 0x00
    s0:
	CPFSEQ s
	BRA s1
	BRA  end_
    s1:
	INCF WREG
	CPFSEQ s
	BRA  s2
	RLCF LATA
	BRA  end_
    s2:
	INCF WREG
	CPFSEQ s
	BRA s3
;	RLCF LATA
	MOVLW 0x0C
	MOVWF LATA  
	BRA end_
    s3:
	INCF WREG
	CPFSEQ s
	BRA end_
	MOVLW 0x09
	MOVWF LATA 
	
    end_:
    
endm 
	
initial:  
    
    MOVLW 0x00
    MOVWF count
    MOVWF state
    ; let pin can receive digital signal     
    MOVLW 0x0f
    MOVWF ADCON1
    CLRF PORTB
    BSF TRISB, 0
    CLRF LATA     ; output value
    BCF TRISA, 0 ; tell if its output(0) or input(1) 
    BCF TRISA, 1 ; tell if its output(0) or input(1) 
    BCF TRISA, 2 ; tell if its output(0) or input(1) 
    BCF TRISA, 3 ; tell if its output(0) or input(1) 
    
; ckeck button
check_process:       
    MOVLW 0x00
    MOVWF count
    MOVFF state, state_count
    BTFSC PORTB, 0    ; Bit Test f, Skip if clear
    BRA check_process ; not press
    BRA lightup       ; if press

;light up oled
lightup:	    
    check_light state_count
    delay 0x01 ;delay 500ms
    INCF count
    add_state state_count
    MOVLW 0x04
    CPFSEQ count
    BRA lightup
    add_state state    
    delay 0x02 ;delay 500ms
    CLRF LATA
    BRA check_process  

end

Result

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demo

Reference

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How to Use a Breadboard and Build a LED Circuit
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How to write delay in MPLAB
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PIC18Fxxx Instruction Set

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