This page investigates the Super Probe program written by by Luhan Monat of mondo-technology.com.
The only way to investigate and diagnose such a complex program is to pull it apart and start from the beginning.
This program combines YEARS of skill and understanding of circuit-design, program development as well as mathematical number-manipulation, to produce results on the display.
Explaining some of the mathematical-processing code is beyond the scope of this discussion and you will have to accept these sub-routines and use them "as is" whenever they are required.
However most of the program can be pulled apart and studied to see how it operates.

LOOKING AT THE SCAN ROUTINE
The first thing to do is look at the display routine. This is called the SCANNING ROUTINE and it outputs to the display "ONE PIXEL or SEGMENT AT A TIME." This is an unusual way to drive a display but has been chosen so that all the segments have the same brightness and the scan routine does not put too much load on the outputs of the micro.
You will notice the absence of current liming transistors.
This is not a good practice as it loads the FETs in the micro so that they do not turn on fully.
You can imagine show small each FET is.
They are designed to deliver up to 25mA when fully turned on.
This means the dissipation is only a few milliwatts, if the voltage across it is about 50mV.
But when you are driving a LED, the voltage increases because the LED has a characteristic voltage that does not increase and the remaining voltage must be dropped across the driving components.
The circuit uses two outputs to turn on each segment and if the voltage across the LED is 1.7v, each output has to drop: 5v - 1.7v = 3.3v This voltage is divided by two to get 1.65v
The power dissipated by each FET rises from 25x50 = one thousandth of a milliwatt, to 25x1650 = forty-one thousandths of a milliwatt. It has increased 40 times.
The FETs seem to be very robust and none have failed to-date.
To see how the display is accessed, we need to remove the code that does not apply to this function and leave only the display (scan) sections.
To do this we gradually remove sub-routines and save the new program as Scan_v43only.asm You must give it a new name so you can go back to previously-saved versions if the new version does not work. This is burnt into a chip and tested to make sure the start-up feature is still present.
More un-wanted sub-routines are removed until we get the smallest program possible.
This is what we have done.
In addition, we have increased the delay so the display routine runs very slowly and you can see it in action.
The first thing the program does is display the version number. In this case it is 043. There are more sub-routines than are really needed for this task, in the program below, but they are included  because they are "called."
The length of delay starts very short and increases by increasing the three files using the "rate" file.
The display scans "043" very quickly, then gets slower and slower to show how each segment is accessed and displayed.
The file you need is:

Scan_v43only.asm
Scan_v43only.hex
 

;Scan the version number 043 ;list p=16f870A ; list directive to define processor #include ; processor specific variable definitions errorlevel -302 ; Register not in bank 0 warning radix dec __CONFIG _CP_OFF & _WDT_OFF & _BODEN_OFF & _PWRTE_ON & _HS_OSC & _LVP_OFF & _DEBUG_OFF & _CPD_OFF #define VERS 043 ;Version to display ; Data storange org 20h wsave equ 20H ssave equ 21H bitcnt equ 22H ; flag equ 23H count equ 24H scount equ 25H csave equ 26H ddata equ 27H sdata equ 28H temp equ 29H ontime equ 2BH oftime equ 2CH isrvec equ 2DH qtime equ 2EH ;comm timer for serial timer equ 30H freq equ 33H pwmp equ 35H mode equ 36H rate equ 37H baud equ 38H midic equ 39H ;midi channel pmode equ 3AH hi equ 3BH lo equ 3CH rand equ 3DH acc equ 40H xacc equ 44H digits equ 48H dignr equ 4CH dp equ 4DH ftimer equ 4EH segmask equ 50H dela equ 51H bcd equ 54H cnt equ 59H ii equ 5AH frame equ 5BH place equ 5Ch port_temp equ 5Dh ; Program Start org 0 goto start ; Table for number to seven segment conversion digseg addwf PCL,f retlw 3fh ;0 retlw 6h ;1 retlw 5bh ;2 retlw 4fh ;3 retlw 66h ;4 retlw 6dh ;5 retlw 7dh ;6 retlw 7h ;7 retlw 7fh ;8 retlw 67h ;9 ; Get anode value for PORT C output getano addwf PCL,f retlw 1 retlw 2 retlw 4 retlw 8 getdp addwf PCL,f retlw 03h retlw 03h retlw 03h retlw 03h retlw 94h retlw 0A5h retlw 0C6h retlw 0D7h retlw 0E8h retlw 0F9h start bsf STATUS,5 movlw b'00111111' movwf TRISA movlw 0 movwf TRISB movlw b'10110000' movwf TRISC movlw b'10001000' movwf OPTION_REG bcf STATUS,5 clrf segmask bsf segmask,0 clrf dignr clrf rate ;used to decrease scan rate for viewing call signon goto start ; show version No signon movlw VERS call wtod ;put version No movlw 0 movwf digits call sign return ; delay function delay movwf dela+2 dld2 movwf dela+1 dld1 movwf dela dld0 decfsz dela,f goto dld0 decfsz dela+1,f goto dld1 decfsz dela+2,f goto dld2 return ; show 8 bit value on display wtod movwf acc clrf acc+1 clrf acc+2 clrf acc+3 call b2bcd call format return sign movlw .30 movwf temp x1 call segout incf rate,f movf rate,w ;decrease scan rate across display call delay decfsz count,f goto x1 decfsz temp,f goto x1 return ; Convert 32-bit binary number at into a bcd number ; at . Uses Mike Keitz's procedure for handling bcd ; adjust; Modified Microchip AN526 for 32-bits. b2bcd movlw 32 ; 32-bits movwf ii ; make cycle counter clrf bcd ; clear result area clrf bcd+1 clrf bcd+2 clrf bcd+3 clrf bcd+4 b2bcd2 movlw bcd ; make pointer movwf FSR movlw 5 movwf cnt ; Mike's routine_ b2bcd3 movlw 33h addwf 0,f ; add to both nibbles btfsc 0,3 ; test if low result > 7 andlw 0f0h ; low result >7 so take the 3 out btfsc 0,7 ; test if high result > 7 andlw 0fh ; high result > 7 so ok subwf 0,f ; any results <= 7, subtract back incf FSR,f ; point to next decfsz cnt,f goto b2bcd3 rlf acc+0,f ; get another bit rlf acc+1,f rlf acc+2,f rlf acc+3,f rlf bcd+0,f ; put it into bcd rlf bcd+1,f rlf bcd+2,f rlf bcd+3,f rlf bcd+4,f decfsz ii,f ; all done? goto b2bcd2 ; no, loop return ; cycle thru individual segment drives on 4 digits ; (constant execution time_ 30 instructions) ; ************** Do Not Modify ******************* segout movlw 0F0h andwf PORTC,f ;clear low 4 bits movf dignr,w ;get digit nr addlw digits ;base of segment list movwf FSR movf 0,w ;get the data andwf segmask,w ;mask the bit xorlw 0ffh ;invert movwf PORTB ;one possible segment line low movf dignr,w call getano iorwf PORTC,f ; set one high. bcf STATUS,C rlf segmask,f btfsc STATUS,C goto nseg nop nop nop nop nop return nseg bsf segmask,0 ;rotate incf dignr,f btfsc dignr,2 ;overflow? clrf dignr return ; format first 4 significant digits on display format call first ;find 1st non-zero digit ffx movf count,w call getdp ;get formatting info movwf dp andlw 0fh movwf count ff5 call ff9 ;get segment pattern movwf digits call ff9 movwf digits+1 call ff9 movwf digits+2 call ff9 movwf digits+3 return ff9 movf count,w decf count,f call getbd ;get bcd value call digseg return ; set count to 1st non zero digit first movlw 9 ;start w/last digit movwf count ff2 movf count,w ;get next digit call getbd xorlw 0 ;set z flag btfss STATUS,Z return ;hit non zero decfsz count,f goto ff2 return ; get bcd digit specified by 'w' getbd movwf temp ;save digit No clrw btfsc temp,7 ;negative value? return ;zero if negative. bcf STATUS,C rrf temp,f ;find buffer offset movf temp,w rlf temp,f ;restore all bits addlw bcd ;add start of bcd buff movwf FSR ;set pointer movf 0,w ;get the byte movwf ddata ;and store it. btfsc temp,0 ;low or hi nibble? swapf ddata,f ;hi. movf ddata,w andlw 0fh return end

 

;Scan the version number.asm ; END