John

Just to warn you! You have used all of PortB unless the other bits are
inputs and you have set up the TRISB port up. If you want to use the other
half for outputs  you will have to mask them off

This code just alters the lower half of the port

loop:
temp = portb & $F0 ' clear low bits
portb = temp | 1   ' add in the new lower bits and write back
temp = portb & $F0
portb = temp | 2
temp = portb & $F0
portb = temp | 3
....
temp = portb & $F0
portb = temp | 14
temp = portb & $F0
portb = temp | 15
ptemp = portb & $F0
portb = temp | 14
....
temp = portb & $F0
portb = temp | 2
temp = portb & $F0
portb = temp | 1
goto loop

Tim


-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of moonshadow
Sent: 04 June 2003 19:41
To: PICLIST@MITVMA.MIT.EDU
Subject: Sinewave generation .... Thanks


Thanks to all those who made suggestions. In the end I unrolled the loop and
used straight ...

PORTB = 8
PORTB =  9 etc etc
Goto beginning

and the frequency shot up by almost a factor of ten !. So I have included a
delay of 1 uS at each point and fine tuned the frequency by adjusting the
number of points in each cycle. I am well pleased with the  results for the
price of half a 628 port and five resistors. Thanks again chaps ...... John
Kent

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