Series resistor in any scenario controls the current. Without that, pin draws current based on its input impedance. In scenarios where is there is a strong PD internally, pin drawing current for a long time might damage it..
@@Way2Know hmm. I think there's more to it.. if that were true (if it fall time would be proportional to the pull-up resistance) , then if you'd make the pull up resistance higher, the fall time would also increase.. let me think more and get back.
Yes, you are right.. that is why I was saying approximation.. think it this way, if you are increasing the resistance, the charge current is reduced and hence time as well.. vice-versa for fall
Great video, i have a quick question so i have a raspberry Pi 3 and i connect the pull resister of 4.7k and to the I2C Bus i have 34 devices that works well, when i connect the final 6, i start loosing data over the bus, does this mean i can lower my pull-up resistor to 2.2k so that i dont encounter data lost?
When you calculate the RC value, the RC must be such that you should not increase the rise time too much.. incase your circuit, you are increasing the capacitance on the bus by adding additional devices.. So, your RC is increasing all the time.. To bring it under control, you must have to reduce the PU. As you said, you can try with 2.2k and check how it is going..
@@Way2Know Thank you so much for your quick reply. For my master i am using Raspberry Pi 3b+ and all my slaves are Rpi Picos. I will let you know how it turn out.
@@Way2Know Thank you so much the 2.2k works, now i have all 40 rpi Picos Slave talking to the Rpi 3B+ Master and not loosing and data through the I2C Bus
well explained!!
Thank you 🙂
Very important and practical point covered from I2C. Very well conveyed. Thank You for your effort and time :)
Thank you 😊
It is so useful,
Explained practically.
Thank you Sir
Thank you 😊
Excellent explaination mam
Lets say while working with 5v controller what if we directly connect the 5v line to I2C bus without any resistor. Why resistor is necessary?
Series resistor in any scenario controls the current. Without that, pin draws current based on its input impedance. In scenarios where is there is a strong PD internally, pin drawing current for a long time might damage it..
@@Way2Know Thank you very much
very well explained! How do you calculate the fall time?
To keep it simple, can be approximated by the time constant value RC
@@Way2Know Is R the pull-up resistance in this case?
Yes.. the discharge path shall be through pull-up resistor and capacitance
@@Way2Know hmm. I think there's more to it.. if that were true (if it fall time would be proportional to the pull-up resistance) , then if you'd make the pull up resistance higher, the fall time would also increase.. let me think more and get back.
Yes, you are right.. that is why I was saying approximation.. think it this way, if you are increasing the resistance, the charge current is reduced and hence time as well.. vice-versa for fall
Great video, i have a quick question so i have a raspberry Pi 3 and i connect the pull resister of 4.7k and to the I2C Bus i have 34 devices that works well, when i connect the final 6, i start loosing data over the bus, does this mean i can lower my pull-up resistor to 2.2k so that i dont encounter data lost?
When you calculate the RC value, the RC must be such that you should not increase the rise time too much.. incase your circuit, you are increasing the capacitance on the bus by adding additional devices.. So, your RC is increasing all the time.. To bring it under control, you must have to reduce the PU. As you said, you can try with 2.2k and check how it is going..
@@Way2Know Thank you so much for your quick reply. For my master i am using Raspberry Pi 3b+ and all my slaves are Rpi Picos. I will let you know how it turn out.
Ready to help you anytime..
@@Way2Know Thank you so much the 2.2k works, now i have all 40 rpi Picos Slave talking to the Rpi 3B+ Master and not loosing and data through the I2C Bus
Good to know..