I have been having a problem where my program resets itself at random times
in my code, so I used the mplab simulator software and found that in one
routine when I try and modify the PCL (program counter right?) to make it
jump forward in the code a few lines, it jumps to a random place in code far
from what was intended.  So basically, do you see any memory problems in
this section of code, especially around where you see the cblock?  If not
what typically causes the PIC to reset itself?  I don't include the code
where the problem actually occurs for brevity and I am also pretty certain
that my problem lies in this section here.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
        LIST    p=16F628                ;tell assembler what chip we are
using
        include "P16F628.inc"           ;include the defaults for the chip
        ERRORLEVEL      0,      -302    ;suppress bank selection messages
        __config 0x3D18                 ;sets the configuration settings
(oscillator type etc.)
        ;__CONFIG   _CP_OFF & _WDT_OFF & _PWRTE_ON & _INTRC_OSC_NOCLKOUT &
_LVP_OFF & _MCLRE_OFF

#define RXBIT PORTB, 3
#define IF_SHORT flags, 0
#define FIRST_HALF flags, 1
#define HEADER flags, 2
#define VALID flags, 7

if_short_val    EQU     1 ; bit value of IF_SHORT flag
first_half_val  EQU     2 ; bit value of FIRST_HALF flag


                cblock  0x20                    ;start of general purpose
registers
                        count                   ;used in looping routines
                        count1          ;used in delay routine
                        counta          ;used in delay routine
                        countb          ;used in delay routine
                        tmp1                    ;temporary storage
                        tmp2
                        templcd         ;temp store for 4 bit mode
                        templcd2
                endc

bitcnt  res     1
tmrval  res     1 ; timer value
bt              res     1 ; receive byte buffer
flags           res     1 ; decode logic status
btcnt           res     1 ; byte counter
agetmr  res     1 ; age out timer
buffer  res     4 ; receive packet buffer
bsum            res     1 ; receive buffer, checksum


;FOR LCD
LCD_PORT        Equ     PORTA
LCD_TRIS        Equ     TRISA
LCD_RS  Equ     0x04                    ;LCD handshake lines
LCD_RW  Equ     0x06
LCD_E           Equ     0x07

hdrcntmin       EQU     0x0c
hdrcntmax       EQU     0x10

min_t           EQU     .34
min_2t  EQU     .104
max_2t  EQU     .174

age_max EQU     .15 ; age out last valid packet
packet_len      EQU     5 ; packet length, check var. alloc!
devid1  EQU     0x9a
devid2  EQU     0xe9

                org     0x0000
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;begin normal code execution;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;


Richard Zinn
Software Engineer
richardz@omniture.com
801.722.7000 ext. 158 tel
801.319.6078 cel

Omniture
http://www.omniture.com
"Unique Questions, Precise Answers"


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