please tell me how at89c51 sense logic 0&1 means at witch voltage

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karan29

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i m doing project with at89c51 i want to know how ldr is inter faced with this controller ,i also inter face npn proximity switch which produce 0.5mv at output on sensing .so i want to know at which voltage controller sense logic 0&when 1 so i can programming according to it
 

Re: plesse tell me how at89c51 sense logic 0&1 means at witch voltage

The circuit mentioned above works but .....In my view first measure the resistance of the LDR when light fall on it and when light is not present then it will be helpful for fine tuning the circuit parameters...

Good Luck
 

Re: plesse tell me how at89c51 sense logic 0&1 means at witch voltage

milind.a.kulkarni said:
The circuit mentioned above works but .....In my view first measure the resistance of the LDR when light fall on it and when light is not present then it will be helpful for fine tuning the circuit parameters...

Good Luck
Click to expand...

ya but first i want to inerface proximity switch which produce 0.5mA at sencing can i directly connect it witch int0 pin of at89c51?????????????
i want to know how much voltage required to sense controller logic 0 or 1
 

Re: plesse tell me how at89c51 sense logic 0&1 means at witch voltage

karan29 said:
ya but first i want to inerface proximity switch which produce 0.5mA at sencing can i directly connect it witch int0 pin of at89c51?????????????
i want to know how much voltage required to sense controller logic 0 or 1
Click to expand...

Hai.. Do you have datasheet for AT89C51? Please refer the DC characteristics of AT89C51.



The above picture shows you the DC characteristics of AT89C51. Hope you will find it useful

Thanks
 

Re: plesse tell me how at89c51 sense logic 0&1 means at witch voltage

karan29 said:
ya but first i want to inerface proximity switch which produce 0.5mA at sencing can i directly connect it witch int0 pin of at89c51?????????????
i want to know how much voltage required to sense controller logic 0 or 1
Click to expand...

low logic 0 – 1.8V dan high logic 2.2V – 5V
 
Re: plesse tell me how at89c51 sense logic 0&1 means at witch voltage

Li_ereunpisan said:
low logic 0 – 1.8V dan high logic 2.2V – 5V
Click to expand...

its for at89c51 na?????????????????????

---------- Post added at 13:58 ---------- Previous post was at 13:55 ----------

its for at89c51 na????????????

---------- Post added at 13:59 ---------- Previous post was at 13:58 ----------

thnx............
 

Re: plesse tell me how at89c51 sense logic 0&1 means at witch voltage

Li_ereunpisan said:
low logic 0 – 1.8V dan high logic 2.2V – 5V
Click to expand...

You mean 0 - 0.8V, right? range at 0.8 - 2.2V is unpredictable logic. e.g voltage at 1.5V is mostly acknowledged as High logic, but it is not guaranteed.
 

Re: plesse tell me how at89c51 sense logic 0&1 means at witch voltage

Arch Zone said:
You mean 0 - 0.8V, right? range at 0.8 - 2.2V is unpredictable logic. e.g voltage at 1.5V is mostly acknowledged as High logic, but it is not guaranteed.
Click to expand...

not i mean ... 0 -1.8V .. because I've tried it .. voltage is read logic low by the microcontroller ....
we talk again in a 5V power supply and analog output voltage will vary, but according to the above range
 

Re: plesse tell me how at89c51 sense logic 0&1 means at witch voltage

Li_ereunpisan said:
not i mean ... 0 -1.8V .. because I've tried it .. voltage is read logic low by the microcontroller ....
we talk again in a 5V power supply and analog output voltage will vary, but according to the above range
Click to expand...

Where are v supposed to give this power supply?? I mean at which pin?
 

Re: plesse tell me how at89c51 sense logic 0&1 means at witch voltage

Nidhitrivedi said:
Where are v supposed to give this power supply?? I mean at which pin?
Click to expand...


I attach a picture to behold .. there is a +5 v VCC, if the pin to the 89C51 up to you according to your needs
 

Re: plesse tell me how at89c51 sense logic 0&1 means at witch voltage

ok got that... thanks....
 

Re: plesse tell me how at89c51 sense logic 0&1 means at witch voltage

 

@Nidhi:i m calculating rpm of exhaust fan nd useing controller vary speed of moter also interface lcd,co sensor nd measure smoke density sensor

---------- Post added at 09:29 ---------- Previous post was at 09:27 ----------

I want to calculate smoke density in furnace chamber can any one tell me how i can do it? Plz..
 

i am useing msp430f4270 controller. i want to reduce brightness of led display how i can reduce it?
 

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