Hi all,
Regarding port A, why is it when I connect a low voltage into it from a photodiode, the voltage of the photodiode (and so the voltage at the pin) increases ? The open circuit voltage is 0.25V, and when I connect to AN0 it increases to 0.48V ?
The photodiode negative is connected to gnd and positive to the pin.
When I connect the variable voltage on my programmer board the voltage at pin also increases (tried for 0.6V, 1V, 2.5V). But when I connect voltage from a LM385-2.5 voltage reference it does not increase.
Is this a common occurrence with port A/PICs ? Anyone have any clue ? Im using PIC16F877A.
Thank you all.
edit: this happens with all the channels of port A. When nothing is connected, all pins of port A is at +5V.
Regarding port A, why is it when I connect a low voltage into it from a photodiode, the voltage of the photodiode (and so the voltage at the pin) increases ? The open circuit voltage is 0.25V, and when I connect to AN0 it increases to 0.48V ?
The photodiode negative is connected to gnd and positive to the pin.
When I connect the variable voltage on my programmer board the voltage at pin also increases (tried for 0.6V, 1V, 2.5V). But when I connect voltage from a LM385-2.5 voltage reference it does not increase.
Is this a common occurrence with port A/PICs ? Anyone have any clue ? Im using PIC16F877A.
Thank you all.
edit: this happens with all the channels of port A. When nothing is connected, all pins of port A is at +5V.
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