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simple questions

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blibala

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i suddenly wondering about some questions
(1)what is the input voltage( for the pin set as input) so that the PIC16f877 will interpret it as the logic high? is it same for all PIC microcontrollers? i had tried with 5V dc.is it ok?

(2)if a pin is set as output, what is the output voltage from the pin?is it same for all ports?

(3)if i want to turn on a transistor connected (with series resistor)to the pin, is it sufficient to ON the transistor?
 

motion

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(1)what is the input voltage( for the pin set as input) so that the PIC16f877 will interpret it as the logic high? is it same for all PIC microcontrollers? i had tried with 5V dc.is it ok?
Looking at the 16F877 datasheet Doc #30292B under "DC characteristics", input high voltage is from 2.0V-Vdd (param# D040) for TTL compatible inputs and 0.8Vdd-1.0Vdd(param# D041) for Schmitt trigger type inputs. You have to read which ones are which from the datasheet.
(2)if a pin is set as output, what is the output voltage from the pin?is it same for all ports?
See the same datasheet parameter D080 and D090.
(3)if i want to turn on a transistor connected (with series resistor)to the pin, is it sufficient to ON the transistor?
The PIC can source a maximum of 25mA of current. Multiply this by the transistor's Hfe and you can get the maximum current the transistor can conduct and still be saturated(ON).
 
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