Single PIC to Blink 5 LEDs Independently?

[Darrel Taylor]

On the 12F683, the CCP1IF bit is PIR1.5.
Why they have to change things all the time ... I don't know.

CCPIF         VAR PIR1.5

Both the OSCCON and CMCON0 values don't have enough digits.
added: CMCON0 won't matter cause it's still 7, but to keep things consistent ...

OSCCON   = %01110000        ' 8Mhz
CMCON0   = %00000111	    ' Turn off comparators

Not sure how this got changed, it should be ...

FOR x = 0 to (LEDcount - 1)           ; Load the periods from EEPROM

[Amoque]

Again, not wholly sure what your trying to do... I have trouble following someone else's code (even my own sometimes), but a PWM output tied to one input of each (yes, 5) "AND" gate, the other input to each I/O. Toggling I/O then controls modulated output. I am thinking of IR communications where a serial data stream and 38K PWM are "ANDed" for IR transmission.

[RossWaddell]

Again, not wholly sure what your trying to do... I have trouble following someone else's code (even my own sometimes), but a PWM output tied to one input of each (yes, 5) "AND" gate, the other input to each I/O. Toggling I/O then controls modulated output. I am thinking of IR communications where a serial data stream and 38K PWM are "ANDed" for IR transmission.

I was initially intending to make the brightness of the LEDs controllable via PWM, but now the chips are moving off the main board to another PCB that will be buried deep within my model where they will only have +5V & GND wires. These boards are too small to add any other components (even SMTs) so I'll just have to breadboard them with various series-limiting resistors to get the right brightness.

Your suggestion is something I will investigate for the rest of my circuit where I do intend to provide brightness control on the main board. Right now, I'm daisy-chaining 2 NPNs which someone on SparkFun suggested but I haven't breadboarded it yet to see if it works.

[Darrel Taylor]

BTW, what software is that you are using to test out the code?

It's Proteus Design Suite from Labcenter Electronics.

I was initially intending to make the brightness of the LEDs controllable via PWM, ... so I'll just have to breadboard them with various series-limiting resistors to get the right brightness.

That can be done in software using MIBAM.
The blinky's timer will have to be changed, but it's doable.

[RossWaddell]

Spent a very happy afternoon reading up on MIBAM - can't wait to try it out (is there a later version of the .pbp code or is the v1.0 you posted on the melbas page the one I should use?).

In preparation for that, I converted the now-workiing code to use Timer2. I think that since Timer2 is 8-bit (versus 16-bit for Timer1) that I don't need to worry about using the Least Significant register as you did with Timer1 but can just use TMR2:

CCPR1val      CON EXT      : @CCPR1val = (OSC*1000000/4)/ BLINKYFREQ
;CCPR1         VAR WORD EXT : @CCPR1 = CCPR1L
Timer2        VAR WORD EXT : @Timer2 = TMR2
CCPIF         VAR PIR1.5

And then this to turn it on:

;-- setup CCP1 and Start Timer2 --
CCPR1   = CCPR1val          ; set compare value
CCP1CON = %00001011         ; compare mode, special event 
Timer2  = 0                 ; clear Timer2
T2CON.0 = 1                 ; start Timer2

Is that it?

[RossWaddell]

Or maybe not. The PIC12F683 data sheet seems to indicate that the Compare mode uses only Timer1, and if that's needed for MIBAM then I don't think I can use that on a PIC12F683 with this blinky code.

[Darrel Taylor]

One little obstacle and ... it can't be done???

The CCP with Capture mode was just a simple way to get a wide range of constant periods without interrupts/reloading timers etc.

Since it seems that you are only using the original 10mS periods, it doesn't really need that "Wide Range".
10mS periods can be generated with another Timer, and you don't need the CCP module.

In this example, I'm using Timer0 ...
MIBAM uses Timer1.

The EEPROM data labeled Brightness controls the intensity of each LED.
I have 3 LED's with 330 ohms, and 2 LED's with 100 ohms. The existing values equalized their brightness (to my eyes).

;{PIC=12F683}

#CONFIG
  __config  _INTOSCIO & _WDT_OFF & _PWRTE_OFF & _MCLRE_OFF & _CP_OFF & _CPD_OFF & _BOD_ON & _IESO_OFF & _FCMEN_OFF
#ENDCONFIG


DEFINE OSC 8
OSCCON   = %01110000       ; 8MHz internal osc

ANSEL = 0                  ; All Digital
CMCON0 = 7
OPTION_REG = %00000110     ; Timer0 prescaler 1:128
TMR0IF   VAR INTCON.2      ; Timer0 Overflow bit
TRISIO = 0                 ; all OUTPUT

;----[ MIBAM Setup ]--------------------------------------------------------
wsave       var byte    $70     SYSTEM  ' Alternate save location for W
ssave       VAR BYTE    BANK0   SYSTEM  ' location for STATUS register
psave       VAR BYTE    BANK0   SYSTEM  ' location for PCLATH register

BAM_COUNT CON 5                     ; How many BAM Pins are used?
;DEFINE BAM_INFO 1
INCLUDE "MIBAM.pbp"                 ; Mirror Image BAM module

Bright  VAR BYTE[BAM_COUNT]
Br0     VAR Bright[0]
Br1     VAR Bright[1]
Br2     VAR Bright[2]
Br4     VAR Bright[3]
Br5     VAR Bright[4]

ASM
BAM_LIST  macro                     ; Define PIN's to use for BAM
     BAM_PIN (GPIO,0, Br0)          ;   and the associated Duty variables
     BAM_PIN (GPIO,1, Br1)
     BAM_PIN (GPIO,2, Br2)
     BAM_PIN (GPIO,4, Br4)
     BAM_PIN (GPIO,5, Br5)
  endm
  BAM_INIT  BAM_LIST                ; Initialize the Pins
ENDASM

;----[Setup Blinky parameters]-----------------------------------
DEFINE BLINKYFREQ 100                ; 10mS periods
LEDcount    CON 5                    ; Number of LEDs on the PORT
OnTimes     DATA  50, 22, 38,75, 5   ; default periods for each Output
OffTimes    DATA 150, 45, 38,95,34
Brightness  DATA 150,150,150,80,80

#DEFINE USE_RANDOM_SEQUENCE     ; comment for contiuous Sequence

#IFDEF USE_RANDOM_SEQUENCE

    RND     VAR WORD : RND = 13864
    MIN_ON  CON 50                  ; Minimum random ON time
    MAX_ON  CON 500                 ; Maximum random ON time
    MIN_OFF CON 50                  ; Minimum random OFF time
    MAX_OFF CON 500                 ; Maximum random OFF time
    RandPeriod VAR WORD[LEDcount]
    RandPeriods DATA WORD 1000, WORD 1250, WORD 1500, WORD 1750, WORD 2000
#ENDIF


;----[Variables used only by Blinky]-----------------------------
LoopLED    VAR WORD[LEDcount]
OnTime     VAR WORD[LEDcount]
OffTime    VAR WORD[LEDcount]
x          VAR BYTE

;----[Initialize]------------------------------------------------
FOR x = 0 to LEDcount - 1         ; load the periods from EEPROM
    READ OnTimes+x, OnTime(x)
    READ OffTimes+x, OffTime(x)
    #IFDEF USE_RANDOM_SEQUENCE

        READ RandPeriods+(x<<1), WORD RandPeriod(x)
    #ENDIF

NEXT X


;----[Main Program Loop]----------------------------------------
Main:
    x = (x + 1) // LEDcount
    IF LoopLED(x) < OnTime(x) THEN
        READ Brightness + x, Bright(x)
    ELSE
        Bright(x) = 0
    ENDIF
    LoopLED(x) = (LoopLED(x) + 1) // (OnTime(x) + OffTime(x))
    #IFDEF USE_RANDOM_SEQUENCE

        RandPeriod(x) = RandPeriod(x) - 1
        IF RandPeriod(x) = 0 THEN
            READ RandPeriods+(x<<1), WORD RandPeriod(x)
            RANDOM RND
            OnTime(x) = (MAX_ON - MIN_ON)* RND.HighByte / 255 + MIN_ON
            OffTime(x)= (MAX_OFF - MIN_OFF)* RND.LowByte / 255 + MIN_OFF
        ENDIF
    #ENDIF

    IF x != (LEDcount - 1) THEN Main

Waiting: IF !TMR0IF THEN Waiting
    TMR0 = 99
    TMR0IF = 0
GOTO Main

And yes, I posted a MIBAM version 1.1 several years ago ... but it seems to be gone, or I just can't find it..
Here's the latest version.

[RossWaddell]

On the 12F683, the CCP1IF bit is PIR1.5.
Why they have to change things all the time ... I don't know.

CCPIF         VAR PIR1.5

Both the OSCCON and CMCON0 values don't have enough digits.
added: CMCON0 won't matter cause it's still 7, but to keep things consistent ...

OSCCON   = %01110000        ' 8Mhz
CMCON0   = %00000111	    ' Turn off comparators

Not sure how this got changed, it should be ...

FOR x = 0 to (LEDcount - 1)           ; Load the periods from EEPROM

Thank you SOOOO much, Darrel!

BTW, what software is that you are using to test out the code?