How to blink 8 LEDs at different rates- concurrently?

[mackrackit]

You want them all to come on at the same time and drop out at different rates?

PORTB = %11111111
PAUSE XXX
PORTB = %11111110
PAUSE XXX
PORTB = %11111100
...
LOOP OVER...

Something like that?

[Melanie]

Have as many LED's as you have pins...

	LoopALED var BYTE
	LoopBLED var BYTE
	LoopCLED var BYTE
	LoopDLED var BYTE
	LoopELED var BYTE
	LoopFLED var BYTE
	LoopGLED var BYTE
	LoopHLED var BYTE
	'
	LoopACON con 50
	LoopBCON con 22
	LoopCCon con 38
	LoopDCon con 75
	LoopECon con 17
	LoopFCon con 40
	LoopGCon con 62
	LoopHCon con 13
	'
	TRISB=0
Loop:
	If LoopALED=0 then
		LoopALED=LoopACON
		Toggle PortB.0
		else
		LoopALED=LoopALED-1
		endif
	'
	If LoopBLED=0 then
		LoopBLED=LoopBCON
		Toggle PortB.1
		else
		LoopBLED=LoopBLED-1
		endif
	'
	If LoopCLED=0 then
		LoopCLED=LoopCCON
		Toggle PortB.2
		else
		LoopCLED=LoopCLED-1
		endif
	'
	If LoopDLED=0 then
		LoopDLED=LoopDCON
		Toggle PortB.3
		else
		LoopDLED=LoopDLED-1
		endif
	'
	If LoopELED=0 then
		LoopELED=LoopECON
		Toggle PortB.4
		else
		LoopELED=LoopELED-1
		endif
	'
	If LoopFLED=0 then
		LoopFLED=LoopFCON
		Toggle PortB.5
		else
		LoopFLED=LoopFLED-1
		endif
	'
	If LoopGLED=0 then
		LoopGLED=LoopGCON
		Toggle PortB.6
		else
		LoopGLED=LoopGLED-1
		endif
	'
	If LoopHLED=0 then
		LoopHLED=LoopHCON
		Toggle PortB.7
		else
		LoopHLED=LoopHLED-1
		endif
	'
	Pause 10
	Goto Loop

Homework Done! Melanie's off down the pub...

Now repeat the above (excluding definitions) in less than 8 Lines of Code... (yes it can be done)!

[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);
}

[Melanie]

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