PULSE problems on UBW32

Author	Message
Dave Everett Regular Member Joined: 24/06/2011 Location: Australia Posts: 43	Posted: 04:47am 21 Mar 2012       I have MM3.1 loaded onto a UBW32 and have been testing the PULSE command and found it varies greatly. I am using pin 20 for all my tests and a Saleae logic analyser to measure the pulses. Pulse 20,2 gives varying pulse widths anywhere from 1ms to 1.5ms. If someone else has a UBW32, could they check and see if they are getting similar variability. Thanks, Dave
ernie Newbie Joined: 18/03/2012 Location: Australia Posts: 14	Posted: 05:34am 21 Mar 2012       From the MMBASIC 3.1 manual:   Quote   PULSE pin, width Will generate a pulse on 'pin' with duration of 'width' mS. 'width' can be a fraction. For example, 0.01 is equal to 10 μS This enables the generation of very narrow pulses. The generated pulse is of the opposite polarity to the state of the I/O pin when the command is executed. For example, if the output is set high the PULSE command will generate a negative going pulse. Notes: For a pulse of less than 1 mS the accuracy is ± 1 μS. For a pulse of 1 mS or more the accuracy is ± 0.5 mS. A pulse of more than 1 mS will run in the background. 'pin' must be configured as an output. So if the pulse is 1ms or more, the accuracy drops to ± 0.5 mS as it runs in the background. That may be your problem. Try some pulses less than 1mS and see how accurate it is. Edited by ernie 2012-03-22
Dave Everett Regular Member Joined: 24/06/2011 Location: Australia Posts: 43	Posted: 05:56am 21 Mar 2012       I totally missed that Ernie. I read it as 0.5us not ms, but you're right, the accuracy drops significantly. I'll run some tests next week. Dave