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CY8CKIT-049-42xx different output pin behaviour | Cypress Semiconductor

CY8CKIT-049-42xx different output pin behaviour

Summary: 2 Replies, Latest post by Turtle on 11 Jan 2016 05:57 AM PST
Verified Answers: 1
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Turtle's picture
14 posts


I am using the prototyping kit do control two stepper motors.

The motor drivers need a short pulse of a few microseconds to make a step. In my project there are 2 digital output pins, both set to "strong drive", connected to the same control register. One is routed to P0.1, the other is routed to P1.7. Both are wired to the "step" input of two identical motor drivers.

When I make a short pulse by writing to the control register, P0.1 rises immediately and drops immediately, creating a nice rectangular pulse. P1.7 stays at 0V.

Then I introduced a delay of 100us between the rise and fall commands. P0.1 still shows a nice rectangular pulse, but P1.7 needs about 50us to rise to 5V, then stays at 5V, after 100us it falls to 0V immediately.

I swapped the motor controllers, still the same behaviour.

Then I changed the pin mapping from  P1.7 to P0.2, rewired my board. Now both pins show the same nice rectangular signals.

What is the difference between P0.1 and P1.7? Is P1 "weaker" than P0? I can not find anything in the data sheets.

Best regards,


user_1377889's picture
9281 posts

Under ...\Program Files (x86)\Cypress\ you will find the complete documentation for all your installed Cypress Kits including the schematics. This shows that P1_7 is used with a capacitor as bypass for SAR reference. Remove the cap or use another pin.



Turtle's picture
14 posts

Thanks, Bob, I had only looked at the tables 4.1 and 4.2 and have overlooked the schematics with the capacitors.

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