Learn Microcontroller PIC : Lesson 1 - Introduction to PIC

If you are new to microcontroller, that not the problem . Because this will guide you how to use it. 

So, What is microcontroller? To answer this, you may see this link : microcontroller (from wikipedia) or you also can find it in other sources. For me, understand what is microcontroller is important but not its history because we are focus on the its application.

Now, I introduce PIC microconroller ,PIC (from wikipedia). 

Before start, we need some components:

HARDWARE :

1) 1 - PIC16F877A

2) 2 - 33pF Ceramic Capacitor

3) 1 - 10k ohm resistor (0.25W)

4) 1 - 20MHz crystal 

5) 1 - PICKIT2 (Uic00b programmer)

6) 1 - Breadboard 

7) 1 - LED (any colour but with low current)(tips : not ultra bright LED or big size LED)

8) 1 - 1k ohm resistor (0.25W)

9) Multimeter (optional)

10) some wire (single core) --> 

SOFTWARE :
1) MPLAB or MPLABX 

Ok, when you prepare all the material. You are ready to start learn.

Procedure :

Connect the circuit as show in the below :

#Important : The MCLR pin is a pin to reset (Hardware reset)  the program in the PIC. The PIC will reset when the MCLR pin receive '0' or GND.

After you connect the circuit, let we install MPLAB or MPLABX. The installation tutorial for MPLAB or MPLABX  . The installation will take some time. 

When you done install, you can start to program the PIC . Before that, are we forgot something? Erh ......... Oh ya ... how to connect programmer to PIC? Ok, this can refer to the datasheet of the UIC00b programmer. To solve this, first we need to know what pin should we need to connect? According to the datasheet of the UIC00b page 7. 

From the picture above, that are 6 pin are used which is pin 3, 4, 5, 6, 7, 8, 9. But for our application, pin 9 is unused. If you are not good on soldering , you may can buy this :

 Or you can build your own one . This I will teach you later (maybe in next post) .

When you are connect the UIC00b programmer to your circuit and plug in the USB to your computer. Now you can start program. First , you can follow this tutorial (MPLAB) or (MPLABX).

At here, you may know how to program PIC to light up a LED.

This is the program :

#include <htc.h>

#define _XTAL_FREQ 20000000 // tell PIC the value of the crystal

__CONFIG(0x3F32); // configuration bits

void main() // main program

{

TRISD = 0; //this is to set the pin direction : 0 for output , 1 for input 

RD1 = 1; // this is to set the pin : to light up LED

while (1); // this is must because the PIC program is infinite loop

}

From here, you should know how to program PIC and its basic connection. And have a nice day.

Small project

在这我分享一下，我之前的小小的project： Component 如下： - PIC18F4550, crystal(20Mhz) , capacitor(2X 33pF) - 2 set of IR(LED)  - LM324 - Speaker (8 ohm) - 一些resistor (0.25W 够了) - 2 X LED (任何颜色） 连接如图： 这是coding： CONFIG FOSC=HS ;CONFIG WDT=OFF LIST P=18F4550         ; the microcontroller that this program is written for LIST F=INHX8M          ; the file format chosen #include P18F4550.INC   ; the included file contains all SFR definitions and more a0  equ 0x00 a1  equ 0x01         org 0h         goto    main         org 50h main    clrf    TRISD         setf    TRISC         bsf     PORTD,7;power on         bcf     PORTD,4;off speaker led         bsf     TRISA,0         movlw   0x0B         movwf   a1         btfss   PORTC,0         call    speaker         bra     main speaker;speaker function         btg     PORTD,0         bsf     PORTD,4;on speaker led         call    adcf         call    ADCc         call    TSf         movff   ADRESL,a0         btfsc   PORTC,0         return         bra     speaker T0f     ;timer 0 = 10us         movlw   0xFF         movwf   TMR0H         movlw   0xCE         movwf   TMR0L         movlw   0x88         movwf   T0CON         goto    T0P1 T0P1    btfss   INTCON,TMR0IF         bra     T0P1         bcf     INTCON,TMR0IF         return TSf     ;timer produce due to adc value(max=255)         call    T0f         decf    a0         bnz     TSf         return adcf    ;adc init         movlw   0x03         movwf   ADCON0         movlw   0x0E         movwf   ADCON1         movlw   0x88         movwf   ADCON2         return ADCc    btfsc   ADCON0,1         bra     ADCc         bcf     PIR1,6          return         end 我只是用Timer，ADC和PWM而已。 如何function： 1）接进LM324的IR是为了模仿on-off switch的功能。 2）接进PIC（ADC pin）的IR是要读取它的analogue的data。我用的ADC bit size 是8bit（是可以自己set的）。之后，我把它的data 放进timer function。根据它的data，convert 成delay time。ADC value 越低，frequency越高。