Hi i am using anolog device aduc812 microcontroller i tryed to accesses buit in adc with out giving input i am getting output 0xFFF i.e maximum value in all channel except channel 8 ie temp sensor.taht gives some value ie 423 what is the problem please help me
please tell me adc output is in BCD or HEX formate
i connected -ve terminal of power supply to input and +ve to ground it show some value for fraction of second then once again it shows to maximum value i.e 0xfffh
"with out connecting means it should be give output 0x00"
Because the datasheet specifies this behavior, or because you think that it is logical?
Without anything connected, the input may be very high-impedive (and normally is) so tiny leak currents may charge the input and make the input float to +VCC.
So, did you test what happens if you do connect a voltage source, or at least a resistance (possibly quite big) from the input to ground?
with out connecting means it should be give output 0x00
Maybe that is an expected reading if you don't have anything connected. Why don't you connect something and check what you get?
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