Ronald Cotton says:
What is wrong with the following code? It is supposed created a 2 sec delay; however, when I simulate the code in MPLAB version 5.2, the code causes the program to lock up around 65ms or so.I can successfully generate a 0.5 second delay by changing PostScaler value to 4 instead of 16.
When I program the 2 second delay program into the PIC, the LEDs that I have to PORTB stay on; however, when I program the 0.5 second delay into the chip, the LEDs on PORTB blink every 0.5 seconds.
;********************************************************************** ; This file is a basic code template for assembly code generation * ; on the PICmicro PIC16C74A. This file contains the basic code * ; building blocks to build upon. * ; * ; If interrupts are not used all code presented between the ORG * ; 0x004 directive and the label main can be removed. In addition * ; the variable assignments for 'w_temp' and 'status_temp' can * ; be removed. * ; * ; Refer to the MPASM User's Guide for additional information on * ; features of the assembler (Document DS33014). * ; * ; Refer to the respective PICmicro data sheet for additional * ; information on the instruction set. * ; * ; Template file assembled with MPLAB V3.99.18 and MPASM V2.15.06. * ; * ;********************************************************************** ; * ; Filename: 4720Lab2.asm * ; Date: 01/24/2001 * ; File Version: 1 * ; * ; Author: Ronald J Cotton * ; Company: * ; * ; * ;********************************************************************** ; * ; Files required: * ; * ; * ; * ;********************************************************************** ; * ; Notes: * ; * ; * ; * ; * ;********************************************************************** list p=16c74b ; list directive to define processor #include <p16c74b.inc> ; processor specific variable definitions __CONFIG _CP_OFF & _WDT_ON & _BODEN_ON & _PWRTE_ON & _XT_OSC ; '__CONFIG' directive is used to embed configuration data within .asm file. ; The lables following the directive are located in the respective .inc file. ; See respective data sheet for additional information on configuration word. ;***** VARIABLE DEFINITIONS w_temp EQU 0x20 ; variable used for context saving status_temp EQU 0x21 ; variable used for context saving Channel EQU 0X22 ; Channel Variable Counter EQU 0X23 ; Counter DelayValue EQU 0x24 ; Delay Info EQU 0x25 DelayTemp EQU 0x26 ; variable used for context saving cblock 0x27 ; Beginning unused RAM AdValue:8 ; endc ;********************************************************************** ORG 0x000 ; processor reset vector clrf PCLATH ; ensure page bits are claared goto main ; go to beginning of program ORG 0x004 ; interrupt vector location movwf w_temp ; save off current W register contents movf STATUS,w ; move status register into W register bcf STATUS,RP0 ; ensure file register bank set to 0 movwf status_temp ; save off contents of STATUS register movf DelayValue,w ; move status register into W register movwf DelayTemp ; save off current DelayValue contents btfsc PIR1,TMR2IF ; Handler for Timer2 call IntTimer2 ; Interrupt Handler for Timer2 bcf STATUS,RP0 ; ensure file register bank set to 0 movf status_temp,w ; retrieve copy of STATUS register movwf STATUS ; restore pre-isr STATUS register contents movf DelayTemp,W ; retrieve copy of delay register movwf DelayValue ; restore pre-isr DelayValue register swapf w_temp,f swapf w_temp,w ; restore pre-isr W register contents retfie ; return from interrupt IntTimer2: bcf PIR1,TMR2IF ; Must Clear Int flag for Timer2 decf Counter,F ; Decrease Counter return main: bcf STATUS,RP0 ; movlw 0x31 ; movwf Counter ; call InitTimer2 ; movlw 0xc0 ; movwf INTCON ; movlw 0x4A ; Prescaler=16, PostScaler=16 movwf T2CON ; Since OSC = 4Mhz timer = 1uS bsf T2CON,TMR2ON ; Start Timer MainLoop: call FiveSec call LED goto MainLoop ;********************************************************************************************* ;* Everything in this section represents either initialization code or * ;* helper functions. * ;* * ;* Ronald J.Cotton * ;* 02/02/2001 * ;********************************************************************************************* FiveSec: btfss Counter,7 ; goto FiveSec movlw 0x32 ; addwf Counter,F ; Put Counter back to 50 return LED: comf PORTB ; Toggle PORTB return InitTimer2: bcf STATUS,RP0 ; Ensure Reg Bank 0 clrf T2CON ; Stop Timer2, Pre=1:1, Post=1:1 clrf TMR2 ; Clear Timer2 register clrf PIR1 ; Clear Interrupt Flag register bsf STATUS,RP0 ; Bank1 clrf PIE1 ; Disable all Peripheral Interrupts bsf PIE1,TMR2IE ; Enable only Timer2 movlw 0xf9 ; Timeout Value = 249 movwf PR2 ; clrf TRISB ; Make PortB output bcf STATUS,RP0 ; Back to Bank0 movlw 0xff ; All on movwf PORTB ; Initialize LEDS to be on return END ; directive 'end of program'
Scott Lee Says:
I see _WDT_ON in the config but there are no clrwdt instructions so I'm sure that is a problem when you try to use the 2 second delay on real HW.+
As for MPLAB simulation, yes it seems to pause the execution after some short (in human terms) period of execution. In my experience it isn't reseting the device or anything -- it's like it just decides to insert a break point.
Questions:
| file: /Techref/microchip/delay/sim.htm, 10KB, , updated: 2006/5/26 16:20, local time: 2024/11/21 22:43,
3.12.123.41:LOG IN
|
| ©2024 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions? <A HREF="http://ecomorder.com/techref/microchip/delay/sim.htm"> Are there simulation problems in MPLab with delays?</A> |
| Did you find what you needed? |
Welcome to ecomorder.com! |
Welcome to ecomorder.com! |
.