You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
145 lines
4.2 KiB
145 lines
4.2 KiB
; list p=16f871 ; list directive to define processor
|
|
#include <p16f871.inc> ; processor specific variable definitions
|
|
|
|
__CONFIG _CP_OFF & _WDT_OFF & _BODEN_OFF & _PWRTE_ON & _XT_OSC & _WRT_ENABLE_ON & _LVP_OFF & _CPD_OFF
|
|
;__CONFIG _CP_OFF & _WDT_OFF & _PWRTE_ON & _EXTRC_CLKOUT
|
|
|
|
;**********************************************************************
|
|
M_SAVE_STATE macro
|
|
mov wf w_saved
|
|
movfw STATUS
|
|
movwf status_saved
|
|
endm
|
|
|
|
M_RESTORE_STATE macro
|
|
movfw status_saved
|
|
movwf STATUS
|
|
swapf w_saved,f
|
|
swapf w_saved,w
|
|
endm
|
|
|
|
BANK0 = 0x0
|
|
BANK1 = 0x80
|
|
BANK2 = 0x100
|
|
BANK3 = 0x180
|
|
|
|
;**********************************************************************
|
|
INT_VAR UDATA_SHR
|
|
w_saved RES 1 ; variable used for context saving
|
|
status_saved RES 1 ; variable used for context saving
|
|
|
|
TEMP_VAR UDATA_SHR
|
|
count RES 1
|
|
count2 RES 1
|
|
ledA RES 1
|
|
ledC RES 1
|
|
ledB RES 1
|
|
|
|
;**********************************************************************
|
|
STARTUP CODE 0x000 ; processor reset vector
|
|
nop ; for debugger
|
|
movlw high start ; load upper byte of 'start' label
|
|
movwf PCLATH ; initialize PCLATH
|
|
goto start ; go to beginning of program
|
|
|
|
;**********************************************************************
|
|
INT_VECTOR CODE 0x004 ; interrupt vector location
|
|
goto interrupt
|
|
|
|
;**********************************************************************
|
|
PROG1 CODE
|
|
interrupt
|
|
M_SAVE_STATE
|
|
M_SAVE_STATE ; try using twice a macro
|
|
|
|
; increment duty cycle
|
|
; btfss CCP1CON ^ BANK0,4
|
|
; goto duty_cycle_inc_bit0
|
|
; bcf CCP1CON ^ BANK0,4
|
|
; btfss CCP1CON ^ BANK0,5
|
|
; goto duty_cycle_inc_bit1
|
|
; bcf CCP1CON ^ BANK0,5
|
|
; incfsz CCPR1L ^ BANK0,f
|
|
; goto update_duty_cycle_done
|
|
;duty_cycle_inc_bit0
|
|
; bsf CCP1CON ^ BANK0,4
|
|
; goto update_duty_cycle_done
|
|
;duty_cycle_inc_bit1
|
|
; bsf CCP1CON ^ BANK0,5
|
|
;update_duty_cycle_done
|
|
|
|
; increment count
|
|
decfsz count,1
|
|
goto done
|
|
movlw .10
|
|
movwf count
|
|
|
|
; blink and output
|
|
movfw ledB
|
|
xorlw B'00001111'
|
|
movwf ledB
|
|
movwf PORTB
|
|
|
|
done
|
|
bcf INTCON,2 ; reset TMR0 interrupt flag
|
|
M_RESTORE_STATE
|
|
retfie ; return from interrupt
|
|
|
|
;**********************************************************************
|
|
start
|
|
; initialize microchip
|
|
clrf TMR0 ^ BANK0
|
|
clrf INTCON ^ BANK0
|
|
; clrf PORTA ^ BANK0
|
|
clrf PORTB ^ BANK0
|
|
; clrf PORTC ^ BANK0
|
|
; clrf PORTD ^ BANK0
|
|
; clrf PORTE ^ BANK0
|
|
banksel TRISA ; bank 1
|
|
; clrf TRISA ^ BANK1 ; all outputs
|
|
clrf TRISB ^ BANK1 ; all outputs
|
|
; clrf TRISC ^ BANK1 ; all outputs
|
|
; clrf TRISD ^ BANK1 ; all outputs
|
|
; clrf TRISE ^ BANK1 ; all outputs
|
|
movlw B'11010101' ; set prescaler to 64
|
|
movwf OPTION_REG ^ BANK1 ; and start TMR0 (internal source clock)
|
|
; movlw B'00000110' ; set PORTA and PORTE to be all digital
|
|
; movwf ADCON1 ^ BANK1
|
|
banksel INTCON ; back to bank 0
|
|
bsf INTCON,T0IE ; enable TMR0 interrupt
|
|
bsf INTCON,GIE ; enable all interrupts
|
|
|
|
; initialize PWM
|
|
; CLRF CCP1CON ^ BANK0 ; disable CCP module
|
|
; CLRF TMR2 ^ BANK0 ; clear Timer2 (also set the pre-scaler to 1)
|
|
; MOVLW .1
|
|
; MOVWF CCPR1L ^ BANK0 ; set duty cycle = (CCPR1L+1)/(PR2+1) [25% for (31+1)/(127+1)]
|
|
; banksel PR2 ; select bank 1
|
|
; MOVLW .255
|
|
; MOVWF PR2 ^ BANK1 ; set period = Fosc/4/pre-scaler/(PR2+1)
|
|
; BCF TRISC ^ BANK1,2 ; set CCP1 pin as output
|
|
; banksel PIR1 ; back to bank 0
|
|
; MOVLW B'001100'
|
|
; MOVWF CCP1CON ^ BANK0 ; set PWM mode (the 2 LSBs of the duty cycle are set to '00')
|
|
; BSF T2CON ^ BANK0,TMR2ON ; Timer2 starts to increment
|
|
|
|
; The CCP1 interrupt is disabled,
|
|
; do polling on the TMR2 Interrupt flag bit
|
|
;PWM_Period_Match
|
|
; BTFSS PIR1, TMR2IF
|
|
; GOTO PWM_Period_Match
|
|
|
|
; Update this PWM period and the following PWM Duty cycle
|
|
; BCF PIR1, TMR2IF
|
|
|
|
; initialize variables
|
|
movlw B00000101'
|
|
movwf ledB
|
|
movlw .10
|
|
movwf count
|
|
|
|
; loop forever
|
|
goto $
|
|
|
|
;**********************************************************************
|
|
END |