1. Projekt Anglicky v odborných předmětech, CZ.1.07/1.3.09/04.0002
Anglicky v odborných předmětech "Support of teaching technical subjects in English“
Training program: Mechanic - electrotechnician
Program name: Digital processing - microprocessors
III. class
Microcontrollers
Elaborated by: Vlastimil Vlček
Projekt Anglicky v odborných předmětech, CZ.1.07/1.3.09/
je spolufinancován Evropským sociálním fondem a státním rozpočtem České republiky.

2. Program structure Definition: Initialization: Master program
Subroutines
Tables
Definition of Special function registers
Definition of user registers and variables
Setup of peripheral devices
Setup of initial values of the ports
Setup of data downstream through the ports
Setup of initial values of user registers and variables
Main program loop
Subroutines used in the main program loop
Tables of data constants, conversion tables, texts

3. Program structure An example of definitions: porta equ 0x05
portb equ 0x06
trisa equ 0x85
trisb equ 0x86
status equ 0x03
#define RP0 status,5
#define RP1 status,6 
#define TL1 PORTA,0
#define TL2 PORTA,1
#INCLUDE <P16F883.INC>

4. Program structure
An example of initialization: INIT NOP BANKSEL ANSEL ;Bank selection CLRF ANSEL ;PORTA = DIGITAL I/O BANKSEL TRISA MOVLW b' ‚ ;Setup of data downstream of the A port MOVWF TRISA MOVLW b' ‚ ;Setup of data downstream of the B port MOVWF TRISB MOVLW .0 ;Reset of the C port MOVWF TRISC BANKSEL PORTA RETURN

5. Program structure
An example of a master program: START CALL INIT ;initialization of the microcontroller bsf VYSTUP ;H level on the OUTPUT bit call zpozd ;timeout bcf VYSTUP ;L level on the OUTPUT bit goto START ;and again from the beginning …

6. Program structure
An example of a subroutine: ;delay: delay loop delay movlw '255' movwf counter 1 decfsz counter 1 goto $-1 return

7. Program structure
An example of a table: TAB RETLW b' ' ;character 0 RETLW b' ' ;character 1 RETLW b' ' ;character 2 RETLW b' ' ;character 3 RETLW b' ' ;character 4 RETLW b' ' ;character 5 RETLW b' ' ;character 6 RETLW b' ' ;character 7 RETLW b' ' ;character 8 RETLW b' ' ;character 9 RETLW b' ' ;character E

8. Summary of the subject matter - exercises
What is the difference between a definition and a declaration?
What is a peripheral device in a microcontroller?
Why is it good to set up the initial vaules of the ports before we set up the data downstream in them?
Why do we have to work with so-called banks? Which part of the memory of a microcontroller do they concern?

9. Summary of the subject matter - exercises
What are the advantages and pitfalls of the use of the #define directive?
What is the main principle of creating a master program?
What is the purpose and sense of a subroutine, how is it called and how is it used?
Give an example of the use of a delay loop.
Give an example of the use of a table of constants.

10. References
Datasheet Microchip PIC16F882/883/884/886/887 DS41291E (
Microchip.com: Getting Started with PICmicro MCUs
Microchip.com: MPLAB IDE User’s Guide
Microchip.com: Quick Guide to Microchip Development Tools