Learning the microcontrollers

Today marked the first day where I put in some serious time with learning how to code the MCUs. I decided to work on the code for the servos in the mouth of the hood. It is a little slow going as I am learning the assembly language of the chips as well as understanding its memory architecture. Anyway, the code doesn't do much yet but it actually represents a leap in understanding. The code just loops through looking at two servos (I could expand it to more, just keeping number down for debugging purposes). It makes a decision if it is time to move the servo and if it is, sets the servo up for the move.

I have a lot of code to go but it is coming to me pretty quickly now. To give you an idea of what it looks like... Yeah, this is what I do for fun.

list p=16f887 ; list directive to define processor

#include ; processor specific variable definitions

; '__CONFIG' directive is used to embed configuration data within .asm file.

; The labels following the directive are located in the respective .inc file.

; See respective data sheet for additional information on configuration word.

__CONFIG _CONFIG1, _LVP_OFF & _FCMEN_ON & _IESO_OFF & _BOR_OFF & _CPD_OFF & _CP_OFF & _MCLRE_ON & _PWRTE_ON & _WDT_OFF & _INTRC_OSC_NOCLKOUT

__CONFIG _CONFIG2, _WRT_OFF & _BOR21V

SERVOCOUNT EQU D'2'

MINTIMER EQU D'1000' ;smallest pulse for one end of servo positioning

MAXTIMER EQU D'2000' ;largest pulse for other end of servo positioning

TOTALTIMER EQU D'40000' ;max 40ms

; declare servo arrary

VARIABLES UDATA_SHR

servo_start res 0

servo1_cycle res 1

servo1_duration_high res 1

servo1_duration_low res 1

servo2_cycle res 1

servo2_duration_high res 1

servo2_duration_low res 1

loop_count res 1

;**********************************************************************

RESET_VECTOR CODE 0x0000 ; processor reset vector

nop

goto start ; go to beginning of program

MAIN_PROG CODE

start

movlw SERVOCOUNT

movwf loop_count ; init each servo...

movlw servo_start ; start of the array of servo variables.

movwf FSR ; move the address into FSR

INIT_SERVO

; if cycle is 0, means that we are done at this position and must generate new position and cycle count

decfsz INDF

goto SAME_SERVO_POSITION ;cycle isn't 0 yet, stay at same place.

NEW_SERVO_POSITION

;new cycle count

movlw d'32' ;stay here for 32 cycles of 40ms ~1.2Seconds total. TODO replace this with randomizer

movwf INDF

;new servo position

incf FSR

movlw 0x05 ;move to center position of servo high byte TODO: replace this with randomizer

movwf INDF

incf FSR

movlw 0xDC ;move to center position of servo low byte

movwf INDF

incf FSR

decfsz loop_count, 1 ; are we done?

goto INIT_SERVO

goto INIT_SERVO_END

SAME_SERVO_POSITION ;this servo does not need to be moved yet.

incf FSR ;move to next servo

incf FSR

incf FSR

decfsz loop_count, 1 ;are we done?

goto INIT_SERVO

INIT_SERVO_END

goto $

end