I would like to confirm if I am using the maple's Pin as a digital Input is it in high impedance mode like in arduino duemilanov so that no current flows into the pin from the external circuit and damage the microcontroller .
Digital input query
(3 posts) (3 voices)-
CarlO
MemberThere are 3 modes for digital input,
INPUT (or INPUT_FLOATING)
INPUT_PULLUP
INPUT_PULLDOWNAcording to the STM datasheet, the internal PullUp/PullDown resistance is about 40K when enabled. When using INPUT_FLOATING the impedance would be high. Some pins are 5V tolerant.
See the document here for more information:
http://leaflabs.com/docs/maple/gpio/CarlO
Posted 5 years ago # -
The ST datasheet and reference manual are linked at the bottom of the GPIO documentation and list many electrical characteristics.
The datasheet lists the maximum voltage on input pins as 4v (or 5.5v on "5v tolerant pins") and notes that if you stay within these ranges
In general if you're nervous about connecting anything to a Maple pin because it might be high voltage, power spike, whatever, it's best to use a non-analog-input pin if you can. The analog inputs have less robust digital circuitry and the 12-bit ADCs are very sensitive. In our experience the regular digital pins are pretty robust and I don't remember bricking any boards yet by applying +/- 12v, but we have fried analog inputs using high voltages to the point that they only had 4-5 bits of precision.
Posted 5 years ago #
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