Can Timer0 be used instead of Timer1 in DT Blinky?
Is it possible to use Timer0 instead of Timer1 on a 18F4550 using Darrel's blinky program?
Code:
@ __CONFIG _CONFIG1L, _PLLDIV_5_1L & _CPUDIV_OSC1_PLL2_1L & _USBDIV_2_1L
@ __CONFIG _CONFIG1H, _FOSC_HSPLL_HS_1H
@ __CONFIG _CONFIG2L, _PWRT_OFF_2L & _BOR_ON_2L & _BORV_1_2L & _VREGEN_ON_2L
@ __CONFIG _CONFIG2H, _WDT_OFF_2H
@ __CONFIG _CONFIG3H, _CCP2MX_ON_3H & _PBADEN_OFF_3H & _LPT1OSC_OFF_3H & _MCLRE_ON_3H
@ __CONFIG _CONFIG4L, _STVREN_ON_4L & _LVP_OFF_4L & _ICPRT_OFF_4L & _XINST_OFF_4L
DEFINE OSC 48
ADCON1 = %00001111
INTCON2 = %00000000
T0CON = %10000000 ; Prescaler = 2
' T0CON = %10000001 ; Prescaler = 4
' T0CON = %10000010 ; Prescaler = 8
' T0CON = %10000011 ; Prescaler = 16
' T0CON = %10000100 ; Prescaler = 32
' T0CON = %10000101 ; Prescaler = 64
' T0CON = %10000110 ; Prescaler = 128
' T0CON = %10000111 ; Prescaler = 256
' bit 7 TMR0ON: Timer0 On/Off Control bit
' 1 = Enables Timer0
' 0 = Stops Timer0
' bit 6 T08BIT: Timer0 8-Bit/16-Bit Control bit
' 1 = Timer0 is configured as an 8-bit timer/counter
' 0 = Timer0 is configured as a 16-bit timer/counter
' bit 5 T0CS: Timer0 Clock Source Select bit
' 1 = Transition on T0CKI pin
' 0 = Internal instruction cycle clock (CLKO)
' bit 4 T0SE: Timer0 Source Edge Select bit
' 1 = Increment on high-to-low transition on T0CKI pin
' 0 = Increment on low-to-high transition on T0CKI pin
' bit 3 PSA: Timer0 Prescaler Assignment bit
' 1 = TImer0 prescaler is NOT assigned. Timer0 clock input bypasses prescaler.
' 0 = Timer0 prescaler is assigned. Timer0 clock input comes from prescaler output.
' bit 2-0 T0PS2:T0PS0: Timer0 Prescaler Select bits
' 111 = 1:256 Prescale value
' 110 = 1:128 Prescale value
' 101 = 1:64 Prescale value
' 100 = 1:32 Prescale value
' 011 = 1:16 Prescale value
' 010 = 1:8 Prescale value
' 001 = 1:4 Prescale value
' 000 = 1:2 Prescale value
INCLUDE "DT_INTS-18.bas" ' Base Interrupt System
INCLUDE "ReEnterPBP-18.bas" ' Include if using PBP interrupts
ASM
INT_LIST macro ; IntSource, Label, Type, ResetFlag?
INT_Handler TMR0_INT, _ToggleLED, PBP, yes
endm
INT_CREATE ; Creates the interrupt processor
ENDASM
DEFINE LCD_DREG PORTD
DEFINE LCD_DBIT 4
DEFINE LCD_RSREG PORTE
DEFINE LCD_RSBIT 0
DEFINE LCD_EREG PORTE
DEFINE LCD_EBIT 1
DEFINE LCD_BITS 4
DEFINE LCD_LINES 2
DEFINE LCD_COMMANDUS 1000
DEFINE LCD_DATAUS 50
TRISA = %00000000
TRISB = %00000000
TRISC = %00000000
TRISD = %00000000
TRISE = %00000000
LED1 VAR PORTD.0
LED2 VAR PORTD.1
@ INT_ENABLE TMR0_INT ; enable Timer 0 interrupts
PAUSE 1500 ' wait for PIC and LCD to stabilize
LCDOUT $FE,1,"Timer test Lab X1"
Main:
TOGGLE LED2
PAUSE 500
GOTO Main
ToggleLED:
TOGGLE LED1
@ INT_RETURN
END
Darrel's blinky code works just fine at Prescaler 1 with Timer1 but I can't seem to get any variation in blink speed out of Timer0. I tried a gazillion combinations and I admit I'm not sure about the other settings in T0CON.
I don't have access to a scope right now and this desktop doesn't have enough memory to run Saleae from 1MHz and up.
LED2 was added to confirm I didn't screw up the PIC and it is blinking as expected. LED1 seems to be blinking very fast because it is just slightly paler than the other LEDs on the Lab X1 bargraph.
Or are the blinking so fast at any prescaler that I won't be able to see a difference? I was able to detect "very fast" blinking in Timer1 at 1:1 though.
Robert
PBP v2.60c
Re: Can Timer0 be used instead of Timer1 in DT Blinky?
works for me pic18f45k20
Code:
,****************************************************************
'* Name : UNTITLED.BAS *
'* Author : [select VIEW...EDITOR OPTIONS] *
'* Notice : Copyright (c) 2015 [select VIEW...EDITOR OPTIONS] *
'* : All Rights Reserved *
'* Date : 4/14/2015 *
'* Version : 1.0 *
'* Notes : *
'* : *
'****************************************************************
#CONFIG
CONFIG FOSC = INTIO67
CONFIG FCMEN = OFF
CONFIG IESO = OFF
CONFIG PWRT = OFF
CONFIG BOREN = SBORDIS
CONFIG BORV = 18
CONFIG WDTEN = ON
CONFIG WDTPS = 512
CONFIG CCP2MX = PORTC
CONFIG PBADEN = OFF
CONFIG LPT1OSC = OFF
CONFIG HFOFST = ON
CONFIG MCLRE = ON
CONFIG STVREN = ON
CONFIG LVP = OFF
CONFIG XINST = OFF
CONFIG DEBUG = OFF
CONFIG CP0 = OFF
CONFIG CP1 = OFF
CONFIG CP2 = OFF
CONFIG CP3 = OFF
CONFIG CPB = OFF
CONFIG CPD = OFF
CONFIG WRT0 = OFF
CONFIG WRT1 = OFF
CONFIG WRT2 = OFF
CONFIG WRT3 = OFF
CONFIG WRTC = OFF
CONFIG WRTB = OFF
CONFIG WRTD = OFF
CONFIG EBTR0 = OFF
CONFIG EBTR1 = OFF
CONFIG EBTR2 = OFF
CONFIG EBTR3 = OFF
CONFIG EBTRB = OFF
#ENDCONFIG
define OSC 64
osccon=$70 '64 mhz
OSCTUNE.6=1
pause 2000
Serout2 PORTb.7,84,["ready",13,10]
' T0CON = %10000000 ; Prescaler = 2
' T0CON = %10000001 ; Prescaler = 4
' T0CON = %10000010 ; Prescaler = 8
' T0CON = %10000011 ; Prescaler = 16
' T0CON = %10000100 ; Prescaler = 32
T0CON = %10000101 ; Prescaler = 64
' T0CON = %10000110 ; Prescaler = 128
' T0CON = %10000111 ; Prescaler = 256
' bit 7 TMR0ON: Timer0 On/Off Control bit
' 1 = Enables Timer0
' 0 = Stops Timer0
' bit 6 T08BIT: Timer0 8-Bit/16-Bit Control bit
' 1 = Timer0 is configured as an 8-bit timer/counter
' 0 = Timer0 is configured as a 16-bit timer/counter
' bit 5 T0CS: Timer0 Clock Source Select bit
' 1 = Transition on T0CKI pin
' 0 = Internal instruction cycle clock (CLKO)
' bit 4 T0SE: Timer0 Source Edge Select bit
' 1 = Increment on high-to-low transition on T0CKI pin
' 0 = Increment on low-to-high transition on T0CKI pin
' bit 3 PSA: Timer0 Prescaler Assignment bit
' 1 = TImer0 prescaler is NOT assigned. Timer0 clock input bypasses prescaler.
' 0 = Timer0 prescaler is assigned. Timer0 clock input comes from prescaler output.
' bit 2-0 T0PS2:T0PS0: Timer0 Prescaler Select bits
' 111 = 1:256 Prescale value
' 110 = 1:128 Prescale value
' 101 = 1:64 Prescale value
' 100 = 1:32 Prescale value
' 011 = 1:16 Prescale value
' 010 = 1:8 Prescale value
' 001 = 1:4 Prescale value
' 000 = 1:2 Prescale value
INCLUDE "DT_INTS-18.bas" ' Base Interrupt System
INCLUDE "ReEnterPBP-18.bas" ' Include if using PBP interrupts
ASM
INT_LIST macro ; IntSource, Label, Type, ResetFlag?
INT_Handler TMR0_INT, _ToggleLED, PBP, yes
endm
INT_CREATE ; Creates the interrupt processor
ENDASM
TRISA = %00000000
TRISB = %00000000
TRISC = %00000000
TRISD = %00000000
TRISE = %00000000
LED1 VAR PORTD.0
LED2 VAR PORTD.1
@ INT_ENABLE TMR0_INT ; enable Timer 0 interrupts
PAUSE 1500 ' wait for PIC and LCD to stabilize
LCDOUT $FE,1,"Timer test Lab X1"
Main:
TOGGLE LED2
PAUSE 500
GOTO Main
ToggleLED:
TOGGLE LED1
@ INT_RETURN
END
Re: Can Timer0 be used instead of Timer1 in DT Blinky?
Thanks Richard, it works now?
The only thing I've done is awaken the PC from sleep, but I don't see how that could have changed something.
Sincerely,
Confused in Montreal
Re: Can Timer0 be used instead of Timer1 in DT Blinky?
I do most of my programing with a pickit2 , I reckon every now and then (when I'm not alert) the hex file does not refresh after compiling , and then I keep blowing the same old code into the chip. this causes paranoia to set in
