[SOLVED] AT89S52 logic threshold voltage level

[RAHUL_KUMAR]

I referred datasheet to know the threshold voltage level (Vih,Vil,Voh,Vol) ,but it was not mentioned in atmel datasheet. and simply it mention the operating voltage as 4v to 5.5v.
ques.1) What does the operating voltage represent in terms of threshold voltage level?

ques.2) I read somewhere that microcontroller takes care of only '0' and not '1', does it mean any voltage apart from '0' voltage ,the microcontroller will consider it as '1' ? (in simple way the question is 0.2v input to microcontroller ,whether it will be considered as 0 or 1 ?)

ques3) If operating voltage range is mention like 4v to 5.5v , what logic level will be considered by ucontroller if the input voltage falls within the range of operating voltage(0 or 1), and what logic level if it falls below the operating voltage(0 or 1) ?

 

[KlausST]

Hi,

Q1) For sure the datasheet tells you the values. --> Chaper 27 "DC characteristics"
(If a datasheet doesn´t show the values then I dont call it datasheet.)

Q2) "0" means LOW, it doesn not mean any voltage level
"1" means HIGH, it does not mean any voltage level.
The levels in Volts are shown in the datsheet.

Q3) read datasheet thoroughly.

Klaus

 

[RAHUL_KUMAR]

Hi,

Q1) For sure the datasheet tells you the values. --> Chaper 27 "DC characteristics"
(If a datasheet doesn´t show the values then I dont call it datasheet.)

Q2) "0" means LOW, it doesn not mean any voltage level
"1" means HIGH, it does not mean any voltage level.
The levels in Volts are shown in the datsheet.

Q3) read datasheet thoroughly.

Klaus

where did you find m asking for the meaning of digital voltage level in term os binary?
that was not my question what u answered sir.

i think is not clear. i know the digital voltage terms high and low mean in terms of binary.

(suppose you are interfacing two ICs and both of different voltage level , let say 5v input signal from one IC to 3.3v another ic.
then we must know here the specification and threshold voltage level that is VIH,VIL,VOH,VOL of both the ICs . If the VIH of second IC is not more that 3.3v then certainly giving 5v input would affect the (3.3v ic) . while in vice versa interfacing there is no problem if 3.3v input to 5v ic , VOH of 3.3v IC comes in the range of VIH and VIL OF 5V IC. so logic high gives input to 5v ic and as it is is in the rage of VIH and VIL ,so it will interpret it as high too .

to understand myt quest , the paramter which i want to know for at89s52 ,is mentioned here as example in the first page. plz go to the link https://i.stack.imgur.com/BI093.png

 

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I shouldn't even post this as it was easy to find, obviously you need to learn how to look stuff up.

that was not my question what u answered sir.

You claim KlausST didn't answer your question...

Q1) For sure the datasheet tells you the values. --> Chaper 27 "DC characteristics"
(If a datasheet doesn´t show the values then I dont call it datasheet.)

Well there seems to be a datasheet for the device, that you obviously didn't look hard enough for...(took me 20 seconds to find it).
https://ww1.microchip.com/downloads/en/DeviceDoc/doc1919.pdf
After opening it it took one search for "DC cha" and it shows up as chapter 27 on page 29 just like Klaus said.