scorrpeio
Full Member level 5
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I recently had a tough interview. Some of the questions were very tricky, which I could not answer...
1. In I2C, for Slave device SCL acts as input pin. Then how can slave pull the SCL line low in clock stretching?
2. How many devices can be connected in I2C practically? If it depends on capacitance and limited to 115, what is the use of 10bit addressing
3. Why we use 120ohm terminating resistor in RS485? What is impedance matching? The resistor 120ohm matches the impedance of what? What will happen if I connect 240ohm instead of 120?
4. Can I pass variables into ISR? - I replied ISR doesnt take Argument and doesnt return anything. I have got a response "Answer interms of Yes or NO. Can I pass variables into ISR?" 8-O
5. Can global variable be passed in ISR? (I replied yes.)
Can anybody tell me answers in detail? I am searching on google as well.
---------- Post added at 14:59 ---------- Previous post was at 14:56 ----------
6. In power supply design, why do I connect 1000uF 25V cap at input? What will happen if I connect 100uF and 16V instead?
7. What will happen if electrolytic capacitor is connected in reverse way? I replied that capacitor will blow. Then he asked me what is the reason?
1. In I2C, for Slave device SCL acts as input pin. Then how can slave pull the SCL line low in clock stretching?
2. How many devices can be connected in I2C practically? If it depends on capacitance and limited to 115, what is the use of 10bit addressing
3. Why we use 120ohm terminating resistor in RS485? What is impedance matching? The resistor 120ohm matches the impedance of what? What will happen if I connect 240ohm instead of 120?
4. Can I pass variables into ISR? - I replied ISR doesnt take Argument and doesnt return anything. I have got a response "Answer interms of Yes or NO. Can I pass variables into ISR?" 8-O
5. Can global variable be passed in ISR? (I replied yes.)
Can anybody tell me answers in detail? I am searching on google as well.
---------- Post added at 14:59 ---------- Previous post was at 14:56 ----------
6. In power supply design, why do I connect 1000uF 25V cap at input? What will happen if I connect 100uF and 16V instead?
7. What will happen if electrolytic capacitor is connected in reverse way? I replied that capacitor will blow. Then he asked me what is the reason?