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Does Raspberry Pi need pull-up resistors on I2C?
It’s best if I2C slave devices do not have pull-ups fitted, especially if they are pull-ups to 5V which can damage the Pi’s GPIO.
Why do we need pull up resistors in I2C?
Pullup resistors need to be connected from the I2C lines to the supply to enable communication as shown in Figure 1. The pullup resistors pull the line high when it is not driven low by the open-drain interface.
How many I2C devices can be connected to stm32?
I2C Device Addressing This means that you can have up to 128 devices on the I2C bus, since a 7bit number can be from 0 to 127. When sending out the 7 bit address, we still always send 8 bits. The extra bit is used to inform the slave if the master is writing to it or reading from it.
Is there correct resistance value for I2C pull-up resistors?
– Electrical Engineering Stack Exchange Is there a correct resistance value for I2C pull-up resistors? The datasheet of the 24LC256 EEPROM states that: The SDA bus requires a pull-up resistor to VCC (typical 10 kΩ for 100 kHz, 2 kΩ for 400 kHz and 1 MHz).
When do pull up resistors pull the line high?
The pullup resistors pull the line high when it is not driven low by the open-drain interface. The value of the pullup resistor is an important design consideration for I2C systems as an incorrect value can lead to signal loss.
Where are the terminating resistors for I2C / Twi?
There terminating resistors (somewhere around 120 ohms as I recall) are very much in order. But, for I2C/TWI, its a whole different ball game. You CAN put those resistors anywhere on the line and in the very large proportion of cases, there will be virtually no consequence.
Why does the PCB capacitance affect the I2C bus?
So if your I2C bus, with all the PCB capacitance and pin capacitance added together, winds up with a capacitance large enough, it will work to prevent the rapid changing of a voltage level on that bus, and suddenly you can’t make those quick snaps from logic low to logic high as cleanly as necessary. And how does this funky capacitor get charged?