Blinking Blues Quick Version
Blink Broken[edit]
The blink program ( lightly modified ) gives unexpected results.
Reduced version of issues raised at
The Analyzer Did It[edit]
Right now it looks like the problem is the dangerous prototype logic sniffer. I will be editing all of this later and contact the dangerous prototype folks. Go back and look at Blinking Blues
The Code[edit]
The code in its entirety is:
const int ledPin=6; void setup() { pinMode(ledPin, OUTPUT); } void loop() { while ( true ) { digitalWrite( ledPin, HIGH ); // turn the LED on delayMicroseconds( 5000 ); // wait digitalWrite( ledPin, LOW ); // turn the LED off delayMicroseconds( 5000 ); // wait } }
Results[edit]
In the gif below focus on channel 3, that is pin6 The cursor measurement for 1,2,3,4 are all about 10.1 ms, a value which seems "right". But at cursor 5,6 you can see a pulse of period 11.060 ms. This is the "glitch" ( bad term here ) that I am talking about. It repeats about every 80 ms. This sort of behavior with some different details has been present in every test I have conducted.
I did look at the rise and fall time on my scope, it is about 20 ns. I cannot catch this stretched pulse on my scope, but looking for a 1 ms discrepancy across 80 ns is not really easy on a scope. I did use the single sweep option and mess with a bunch of the variables. Right now I trust the logic analyzer for this more than the scope, you can try to present an argument for why I should not. I have to confess I have not tried my old 100 mhz analog scope on this guy.