Best way to address only 4 pins of a port

Jim Fouch

This may seem simple, but I was wondering what was the best way to clear the states of only 4 pins on a port w/o·disturbing the others.

In my project I'm using Port B (pins 1-3) for an A/D and also pins 4-7 to drive a stepper motor·.

Here is the code I'm using now...

SendMotorCommand:
 Read HalfSteps + StepIndex, Temp1
 RB.7 = 0
 RB.6 = 0
 RB.5 = 0
 RB.4 = 0
 RB = RB or Temp1
Return
 
RelaxMotor:
 RB.7 = 0
 RB.6 = 0
 RB.5 = 0
 RB.4 = 0
Return

 
HalfSteps:
  Data %00000000
  Data %00010000
  Data %00110000
  Data %00100000
  Data %01100000
  Data %01000000
  Data %11000000
  Data %10000000
  Data %10010000

Just wondering is there is a better way to address (clear) the states of only 4 pins on a port.
Thanks,

Jim

Paul Baker

Using the logic operand AND is the most efficient means of clearing a series of bits, RB = RB AND #$0F, would clear bits 4-7, I may have the syntax wrong since I don't use SX/B that much.

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·1+1=10

Bean

Paul,
Without the "#" though. RB = RB AND $0F
Bean.

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·

Paul Baker

Thanks Bean, that was what I suspected was incorrect.

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·1+1=10