The prototype  . .  constructed for this article

I have included the program so you can see how a reader has used his skill.

The arrangement of the LEDs is called CHARLIEPLEXING.
The buzzer is an active buzzer that buzzes when connected to 5v supply.

see more discussion below.

Here are the files you will need:
12Wheel.asm
12Wheel.txt
12Wheel.hex
 

12 LED Wheel ; ;PIC12F629 ;************************************* list p=12f629 radix dec include "p12f629.inc" ;__CONFIG ;_MCLRE_OFF & _CP_OFF & _WDT_OFF & _INTRC_OSC_NOCLKOUT ;Internal osc. __config b'0000000111010100' ;*********General Purpose Registers*************** cblock 20h key_flag key_delay_time add1 add2 wait_flag buzz_flag buzz_time_count time_count1 time_count2 random_data random_data_buff random_stop_flag out_time_data_buff out_data_buff run_count run_count_1 led_on_count time_1ms_data_reg1 delay_1ms_flag temp1 temp2 endc ;***********I/O FUNCTION SET **************** #define SET_SW GPIO,03 #define BUZZ GPIO,02 ;*************TIME DATA SET ****************** #define BUZZ_TIME_DATA .5 ;determines shortness of the beep #define KEY_LONG_PAUSE_TIME .20 #define key_delay_time_DATA .39 ;no difference when changed ;*********** PROGRAM START ************* ORG 000 goto MAIN ;**************************************************** IO_directing movf add1,0 addwf PCL,1 NOP retlw B'00111000' ;LED1 retlw B'00111000' ;LED2 retlw B'00101010' ;LED3 retlw B'00101010' ;LED4 retlw B'00011010' ;LED5 retlw B'00011010' ;LED6 retlw B'00101001' ;LED7 retlw B'00101001' ;LED8 retlw B'00001011' ;LED9 retlw B'00001011' ;LED10 retlw B'00011001' ;LED11 retlw B'00011001' ;LED12 LED_OUT_DATA movf add1,0 addwf PCL,1 NOP retlw B'00000110' ;LED1 ON retlw B'00000101' ;LED2 ON retlw B'00010100' ;LED3 ON retlw B'00000101' ;LED4 ON retlw B'00100100' ;LED5 ON retlw B'00000101' ;LED6 ON retlw B'00010100' ;LED7 ON retlw B'00000110' ;LED8 ON retlw B'00100100' ;LED9 ON retlw B'00010100' ;LED10 ON retlw B'00100100' ;LED11 ON retlw B'00000110' ;LED12 ON LED_ON_TIME_DATA ;these values increase the LED ON-time and make the "wheel" slower and slower. However the beep is the same length. movf add2,0 addwf PCL,1 NOP dt .6,.6,.6,.6,.6,.6,.6,.6,.6,.6,.6,.6 dt .7,.7,.7,.7,.7,.7,.7,.7,.7,.7,.7,.7 dt .8,.8,.8,.8,.8,.8,.8,.8,.8,.8,.8,.8 dt .10,.10,.10,.10,.10,.10,.10,.10,.10,.10,.10,.10 dt .11,.11,.12,.12,.12,.13,.13,.13,.14,.14,.15,.16 dt .17,.19,.21,.23,.25,.27,.29,.30,.31,.32,.33,.34 ;********************************************* MAIN NOP movlw B'00111111' ;make all pins input tris GPIO clrf GPIO ;make all pins LOW One LED will illuminate clrf key_flag clrf add1 clrf add2 movlw .12 movwf add1 movwf random_data movwf led_on_count ;goto KEYSCAN bsf wait_flag,0 bsf random_stop_flag,0 bsf buzz_flag,0 bsf buzz_flag,1 bsf delay_1ms_flag,0 ;**********KEYSCAN********************* KEYSCAN btfss key_flag,0 goto K1 btfss SET_SW ;skip if button not pressed goto $+3 clrf key_flag goto OUTPUT1 btfsc key_flag,3 goto OUTPUT1 movf add2,0 xorlw KEY_LONG_PAUSE_TIME btfss STATUS,Z goto OUTPUT1 clrf add2 bsf key_flag,3 goto OUTPUT1 ; K1 btfsc SET_SW ;skip if button pressed goto OUTPUT1 btfsc key_flag,1 goto $+4 bsf key_flag,1 movlw key_delay_time_DATA movwf key_delay_time K2 btfss delay_1ms_flag,0 goto OUTPUT1 decfsz key_delay_time,1 goto OUTPUT1 btfss SET_SW ;skip if button not pressed goto K3 clrf key_flag goto OUTPUT1 K3 bsf key_flag,0 bsf key_flag,2 clrf random_data clrf add2 clrf run_count clrf run_count_1 bcf random_stop_flag,0 bcf wait_flag,0 movf led_on_count,0 xorlw .12 btfss STATUS,Z goto $+4 movlw 1 movwf led_on_count goto $+2 incf led_on_count,1 ;********LED SCAN OUTPUT************** OUTPUT1 btfss delay_1ms_flag,0 goto tim_1 ;****led stop random data generator*** incf random_data_buff,1 movf random_data_buff,0 xorlw .13 btfss STATUS,Z goto $+3 movlw 1 movwf random_data_buff ;****LED SCAN DISPLAY***************** movlw 0FFH movwf GPIO call IO_directing tris GPIO movlw 0FFH movwf GPIO call LED_OUT_DATA movwf out_data_buff movf add1,0 xorwf led_on_count,0 btfsc STATUS,Z goto OUT2 btfss buzz_flag,1 goto $+4 movlw B'00000100' ;this is buzzer output pin movwf GPIO goto $+3 movlw B'00000000' ;turn ON buzzer movwf GPIO goto OUT3 OUT2 movf out_data_buff,0 movwf GPIO btfsc buzz_flag,1 goto OUT3 bcf out_data_buff,2H movf out_data_buff,0 movwf GPIO OUT3 btfsc buzz_flag,0 goto $+4 bsf buzz_flag,0 movlw BUZZ_TIME_DATA movwf buzz_time_count btfsc random_stop_flag,0 goto $+2 goto $+.10 movf add1,0 xorwf random_data,0 btfss STATUS,Z goto $+.6 movf led_on_count,0 xorwf random_data,0 btfss STATUS,Z goto $+2 bsf wait_flag,0 bcf delay_1ms_flag,0 ;************1ms TIMER ************************* tim_1 movlw 01h movwf temp2 nop decfsz temp1,f goto $-2 decfsz temp2,f goto $-4 bsf delay_1ms_flag,0 ;**************************************************** incf run_count_1,1 incf add1,1 movlw .12 ;counts the 12 LEDs subwf add1,0 btfsc STATUS,Z goto $+5 btfss STATUS,C goto $+3 movlw 1 movwf add1 movlw 8 ;speed of circling xorwf run_count_1,0 btfss STATUS,Z goto KEYSCAN clrf run_count_1 ;**********BUZZ OFF *************************** btfsc buzz_flag,1 goto $+6 decfsz buzz_time_count,1 goto $+4 bsf BUZZ ;make pin2 HIGH = turn off buzzer bsf buzz_flag,1 clrf buzz_time_count btfsc wait_flag,0 goto KEYSCAN incf run_count,1 call LED_ON_TIME_DATA xorwf run_count,0 btfss STATUS,Z goto KEYSCAN clrf run_count clrf buzz_flag incf add2,1 movf led_on_count,0 xorlw .12 ;counts the 12 LEDs btfss STATUS,Z goto $+4 movlw 1 movwf led_on_count goto $+2 incf led_on_count,1 btfsc random_stop_flag,0 goto KEYSCAN btfss key_flag,2H goto $+7 movf add2,0 xorlw .10 ;no effect btfss STATUS,Z goto KEYSCAN clrf add2 goto KEYSCAN movf add2,0 xorlw .60 ;max number of cycles cannot be .65 btfss STATUS,Z goto $+4 movf random_data_buff,0 movwf random_data bsf random_stop_flag,0 goto KEYSCAN END

There is a lot to learn from this program. It is not easy to follow because it does not have any structure.
All the programs l produce have everything laid out in a particular sequence so you know where all the sub-routines will be found in the program. And each instruction is fully documented.
Each sub-routine performs a tiny operation and they are CALLed from the main part of the program.
There are only two CALL instructions in this program and one goes to a data table. This is a set of values and rather than write a line for each value, with a retlw, the line can consist of 20 or more values. This saves time and space. You can access any value at any time and it is very convenient.
The main reason l have included this project is to show different thinking and new ways to produce a program.
And this is the way to learn new skills.
Produce a prototype, as l have done, and go through the program from the start and change the value of an instruction and see what happens. Give each alteration a new file-name so you are sure you will not be re-burnt as an old version.
This way you can go back to an older version if things don’t work.
This way you can see what each section does and what each instruction does, and you will remember it for later, in a future project.
I have changed, removed and simplified the program to get it to this stage and the next thing to do is create sub-routines so you can use them later.
This will involve changing instructions to CALL, instead of GOTO.
You can change the program to make the LEDs cycle in the opposite direction or turn them on randomly. This adds to your understanding.
I use all this understanding to produce other counting and display projects including driving stepper motors, operating servo motors very slowly and creating a speed display for model trains.
Of course you can use a higher-level language to produce the code but the frustration comes when things don’t work.
I prefer to be in charge and do things slowly and simply and without frustration.
Designing, manufacturing and inventing need to be a pleasurable operation, as with designing Printed Circuit Boards and l still use the first CAD package to be produced, some 50 years ago.
At the end of the day, they get the job done and nothing else was available when the PIC chip first came out. It was a one-time programmable chip and you had to use a very expensive erasable version to produce the program. It was UV erasable with a glass window on top and took 10 minutes or more to erase. You needed 5 or 10 of these chips while you were developing a program and even then, you ran out of chips.
The aim is to be able to do everything yourself.
The most difficult part is completing a project. . . .. fixing mistakes and getting it finished.
If you are reliant on programs that you don’t understand, chances are you will be stuck at the end.
That’s why learning via our method is so important. It is simple and relaible.