Charlie-plexing

[towlerg]

Here one I made earlier

Actually simulated, it's the display of a tidal state indicator that one day I'll get round to building. The Xylon effect is just to test all bits with the two elements separate.

George

N2 does work, just a slightly dodgy GIF

[Demon]

...Actually simulated, it's the display of a tidal state indicator that one day I'll get round to building. The Xylon effect is just to test all bits with the two elements separate.

George

Either you messed up recording your GIF, or there's a bug in the top row.

And it's Cylon.

Robert



EDIT: It might also be an Internet Explorer thing, I'm still on XP on my laptop.

[Demon]

I can power pin 1:


I can power pin 4:


But I can't do the same thing at the same time, two unwanted LEDs come on:

Edit: I just noticed I missed another unwanted LED between pins 4 and 2.

I'll probably use a dedicated 18F24K22 running at 64MHz to manage the LEDs. I have to test, but blinking each LED individually might give enough persistence of vision (50 Hz or so).

I was initially planning on powering all LEDs active on one pin, but that might complicate things beyond my limitted abilities. I like to keep things simple.

I might also manage a simple keypad, not sure yet. I have enough pins, but tests will show how much the PIC can manage and still give satisfactory visual effects.

Robert

[Demon]

As I sit down to think how to manage this, one MAJOR drawback:

You had better not forget any LEDs on your project 'cause adding one later is going to be "troublesome".

You can always add it at the bottom of your truth table, but I'm the obsessive compulsive type that likes symetry; LEDs are handled in the logic as they are placed on the circuit board. Remnants of hating spaghetti code on mainframes (COBOL + GOTO = NIGHTMARES).

Robert

[Demon]

Some neat stuff I forgot that I found several years ago on Charlie-plexing.

clear
define osc4
cmcon0=7
ansel=0
adcon0 = 0
@ device mclr_off
@ device wdt_off
@ device bod_off
@ device cpd_off
@ device protect_off

led var byte
ledstates var byte
trisstate var byte
delay var word
noghost var byte
gpnoghost var byte

noghost= %111111
delay= 1500

starthere:
gpio.3 = 0
if gpio.3 = 1 then
  goto main
endif
goto starthere

main:
for led = 1 to 6
  select case led
    case 0 : ledstates =%001 : trisstate =%100
    case 1 : ledstates =%010 : trisstate =%100
    case 2 : ledstates =%001 : trisstate =%010
    case 3 : ledstates =%100 : trisstate =%010
    case 4 : ledstates =%100 : trisstate =%010
    case 5 : ledstates =%010 : trisstate =%001
    case 6 : ledstates =%100 : trisstate =%001
  end select
  trisio = noghost
  gpio = ( gpio & %111000) | ledstates
  trisio = (trisio & %111000) | trisstate
  pause delay
next led

for led = 1 to 5
  select case led
    case 1 : ledstates =%000001: trisstate =%101110
    case 2 : ledstates =%011000: trisstate =%101110
    case 3 : ledstates =%000010: trisstate =%101101
    case 4 : ledstates =%010000: trisstate =%101101
    case 5 : ledstates =%000010: trisstate =%011101
  end select
  trisio = noghost
  gpio = ( gpio & %111000) | ledstates
  trisio = (trisio & %111000) | trisstate
  pause delay
next led

trisio=noghost
gpio=gpnoghost

goto starthere
end

Editted to add some colour, original was black on light gray background.

I wish I could give a link and credit, but I can't find anything on google for this now (been looking for over an hour).

Robert

[AvionicsMaster1]

Did this a while ago. Don't know if it will help. http://www.picbasic.co.uk/forum/showthread.php?t=14220

If you use the above program you'll need to change you define osc line.

Good luck.

[Demon]

I used the wiring above for pins D.1, D.2 and D.3 on a 16F877 and it didn't work as expected.

I get 3 LEDs blinking faintly instead of a single one. It seems as if the current loops over to the unused pin and comes back.

I'll have to check out your thread. I must be missing something.

' Blink 6 LEDs connected to Port D.1, D.2 and D.3 in charlie-plex manner

'   PIC             16F877      ext osc 20MHz
'   PBP             v2.60c
'   MPASM           v5.49
'   MCS+            v2.1.0.7
'   U2 programmer   v4.32

asm
 __config _HS_OSC & _WDT_OFF & _PWRTE_OFF & _BODEN_ON & _LVP_OFF & _CPD_OFF & _WRT_OFF & _DEBUG_OFF & _CP_OFF
endasm

DEFINE OSC 20
ADCON1 = 7                  ' Set Ports to digital
TRISA = %00000000           ' Set all Ports to output 
TRISB = %00000000
TRISC = %00000000
TRISD = %00000000
TRISE = %00000000
PORTA = %00000000           ' Set ports OFF
PORTB = %00000000
PORTC = %00000000
PORTD = %00000000
PORTE = %00000000
    pause 100
mainloop:
    TRISD = %11111001       ' Enable pins D.1 and 2
    PORTD = %00000100       ' Turn ON pin D.2 --> D.1
    pause 500
    PORTD = %00000010       ' Turn ON pin D.1 --> D.2
    pause 500

;    TRISD = %11110101       ' Enable pins D.1 and 3
;    PORTD = %00001000       ' Turn ON pin D.3 --> D.1
;    pause 500
;    PORTD = %00000010       ' Turn ON pin D.1 --> D.3
;    pause 500

;    TRISD = %11110011       ' Enable pins D.2 and 3
;    PORTD = %00000100       ' Turn ON pin D.2 --> D.3
;    pause 500
;    PORTD = %00001000       ' Turn ON pin D.3 --> D.2
;    pause 500

    TRISD = %11111111       ' All pins disabled
    pause 500
    goto mainloop
End

Robert

[Demon]

Did this a while ago. Don't know if it will help. http://www.picbasic.co.uk/forum/showthread.php?t=14220

If you use the above program you'll need to change you define osc line.

Good luck.

LMAO!

I posted YOUR program above! I googled and searched this forum to try and find where I got it from but never found it.

I'll have to look this over again, I must miss something obvious. You have GPIO, I only see PORT and TRIS registers as relevant on a 16F877.

Robert

[Boater]

Hi Demon and AvionicsMaster1
Thank you for the information.
I will try your suggestions though I think typing OR seems the easiest.
Regards
Jim

[richard]

I will try your suggestions though I think typing OR seems the easiest.

Though it looks cool to use those symbols I think it's easier just to type OR and know what it means

.


NOT sure about that , this is what the book says

3.4.2 Logical vs. Bitwise

Logical operators are very different than bitwise operators! There are

circumstances under which PBP will allow the use of logical operators in
expressions. This means that no error message will be generated when you
mistakenly use a logical operator in a bitwise calculation. Consider the following:
result = PORTB AND %00001111
' Returns logical result (1 or 0)
The above example will compile and give a result. The value of the result can only
be one or zero (true or false). If the intent is to use a bitwise operation to obtain a
binary result, you MUST USE BITWISE OPERATORS:

   i_term=0
   d_err=4
   i_err= 3 
   i_term= i_err |  d_err
   serout2 PORTA.0,84,[ "3 | 4 ",9,#i_term, 13,10]
   i_term= i_err OR d_err
   serout2 PORTA.0,84,[ "3 OR 4 ",9,#i_term, 13,10]

PRINTOUT:
3 | 4 7
3 OR 4 65535

[Boater]

Hi Richard
Looking at the PBP3 Compiler Manual it only shows OR as the description for
| in the Bitwise operators. It does show OR as an operator in the Logical operators.

Regards
Jim

[richard]

Logical operators are not bitwise operators
| does a bitwise OR
OR does a Logical OR

2 | 3 = 7
2 OR 3 = ! 0 [ not nothing ]

[AvionicsMaster1]

Yes I made a mistake. There is a difference between bitwise operations and logical operations. I vehemently apologize for the second part of my post.