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

[karan29]

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

 

[Li_ereunpisan]

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

try this.......

View attachment ldr.bmp

 

[milind.a.kulkarni]

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

 

[karan29]

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

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

 

[karthikkrv85]

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

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

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

 

[Li_ereunpisan]

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

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

low logic 0 – 1.8V dan high logic 2.2V – 5V

 

[karan29]

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

low logic 0 – 1.8V dan high logic 2.2V – 5V

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............

 

[Arch Zone]

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

low logic 0 – 1.8V dan high logic 2.2V – 5V

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.

 

[Li_ereunpisan]

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

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.

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

 

[Nidhitrivedi]

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

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

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

 

[Li_ereunpisan]

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

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

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

 

[Nidhitrivedi]

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

ok got that... thanks....

 

[Nidhitrivedi]

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

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?????????????

U can use torodi transformer for connecting proximity switch to microcontroller.... What tyoe of project u making?

 

[karan29]

@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..

 

[karan29]

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