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10 years, 11 months ago.
Should one use resistors to protect an mbed when using it to simulate keyboard key presses?
One can use mbed to act as USBHost or as a USB Device. One use of the latter is to have it emulate a USB Keyboard by sending normal key presses. The general page on using mbed as a USB Device is in the handbook here: http://mbed.org/handbook/USBDevice But looking at the photos of completed projects on that page, for example the one below, there are no resistors used to protect the mbed from power errors coming over the USB connection.
Is that how one should do it? Would it be better to include protection and if so what would the amended schema/diagram be?
1 Answer
10 years, 11 months ago.
I am not into what normal protection would be for commercial devices, but what kind of power errors do you mean? The data lines have small resistors on the mbed itself, but with larger ones you probably get speed issues. And there are of course still the ESD diodes on the microcontroller.
The USB power goes to the Vin pin, which has a voltage regulator, so unless it is really a huge voltage spike that definately shouldn't be a problem.