How to blink 8 LEDs at different rates- concurrently?

[rmteo]

mack, the LEDs need to blink all at the same time, so that will not work.

Mel, use arrays and a for-next loop - along these lines?

Loop:
for x = 0 to 7
  If LoopLED[x] = 0 then
    LoopLED[x] = LoopCON[x]
    Toggle PORTB.x
  else
    LoopLED[x] = LoopLED[x]-1
  endif  
next x
Pause 10
Goto Loop

[Melanie]

Yes, pretty much, but I don't think PortB.x will work, so...

	ShadowPortB=0
Loop:
	for x = 0 to 7
		If LoopLED[x] = 0 then
			LoopLED[x] = LoopCON[x]
			ShadowPortB.0(x)=ShadowPortB.0(x)^1
			else
			LoopLED[x] = LoopLED[x]-1
			endif  
		next x
	PortB=ShadowPortB
	Pause 10
	Goto Loop

Where ShadowPort is a BYTE.

[Darrel Taylor]

Just to be different ...
And because she said "less than 8 Lines of Code" ...

TRISB = 0
Main:
    x = (x + 1) // 8
    PORTB.0(x) = !(LoopLED(x) < LoopCON(x))
    LoopLED(x) = (LoopLED(x) + 1) // (LoopCON(x) << 1)
    if x=7 THEN PAUSE 10
GOTO Main

[Darrel Taylor]

OUCH!

After running my loop in the SIM.
I realized the timing was Waaaayyyyy OFF.
Fortunately, the other examples were "OFF" too ... just not as far.

I've always said PAUSE is the worst statement in the BASIC language.
It got me again.

Here's a version that should compensate ...
It uses the CCP module in "Compare" mode to create a precise 10mS interval.
So when you give a delay value of 50, it actually takes 500mS, on the nose.

Sorry, it's more than 8 lines now.

DEFINE OSC 4
DEFINE BLINKYFREQ 100  ; 10mS periods

DATA 50,22,38,75,17,40,62,13  ; default periods for each Output
;----------------------------------------------------------------
CCPR1val  CON EXT      : @CCPR1val = (OSC*1000000/4)/ BLINKYFREQ
CCPR1     VAR WORD EXT : @CCPR1 = CCPR1L
Timer1    VAR WORD EXT : @Timer1 = TMR1L
CCPIF     VAR PIR1.2

LoopLED   VAR BYTE[8]
LoopCON   VAR BYTE[8]
x         VAR BYTE

;----[Initialize]------------------------------------------------
FOR x = 0 to 7         ; load the periods from EEPROM
    READ x, LoopCON(x)
NEXT X
;-- setup CCP1 and Start Timer1 --
CCPR1   = CCPR1val     ; set compare value
CCP1CON = %00001011    ; compare mode, special event 
Timer1  = 0            ; clear Timer1
T1CON.0 = 1            ; start Timer1

TRISB = 0              ; PORTB all OUTPUT

;----[Main Program Loop]----------------------------------------
Main: 
    x = (x + 1) // 8
    PORTB.0(x) = !(LoopLED(x) < LoopCON(x))
    LoopLED(x) = (LoopLED(x) + 1) // (LoopCON(x) << 1)
    IF x != 7 THEN Main
  Waiting: IF !CCPIF THEN Waiting
    CCPIF = 0
GOTO Main

Cheers,

[Mike, K8LH]

Darrel, that algorithm is slick!

Does PBP allow assignments in expressions like C? For example;

while(1)
{ x = (x+1)&7;
  portb ^= ((!(LoopLED[x]=(LoopLED[x]+1)%LoopCON[x])) << x);
  delay_us(2500);
}

[Darrel Taylor]

Thanks Mike.

Does PBP allow assignments in expressions like C? ...

Nope, not even a +=

However, your x = (x+1)&7 takes much less time than my x = (x + 1) // 8 (Modulus) approach.
What was I thinking?

Cool, thanks!

[keithdoxey]

Thanks Mike.

Nope, not even a +=

However, your x = (x+1)&7 takes much less time than my x = (x + 1) // 8 (Modulus) approach.
What was I thinking?

Cool, thanks!

DOH!!! The problem with working with so many different languages is that you can misread code. I took " //8 " to be a comment (Javascript style) that you were going to do it 8 times LOL

[Melanie]

Personally, I'd have reduced PAUSE by a couple of clicks *smiles*