Contents
Are pull up resistor required 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.
What is the difference between I2C and SPI and UART?
The high bit is in the front and the low bit is in the back. The SPI interface is synchronous serial data transmission between the CPU and the peripheral low-speed device. It is full-duplex communication, and the data transmission speed is overall faster than the I2C bus and can reach speeds of a few Mbps.
What kind of pins do I need for I2C?
On the Arduino the 10k pull-up resistors goto “VDD”, which is the 5V or 3.3V pins. For I2C, if all the slave devices have different device addresses, all of the SDA pins should be connected together, and all of the SCL pins should be connected together.
How is the pull up resistance of an I2C pin determined?
A strong pullup (small resistor) prevents the I2C pin on an IC from being able to drive low. The VOL level that can be read as a valid logical low by the input buffers of an IC determines the minimum pullup resistance [RP(min)]. RP(min) is a function of VCC, VOL (max), and IOL:
What’s the smallest resistor for an I2C bus?
An 18K resistor represents the largest resistor we could use for pullup resistors on the I2C and SPI Education Shield (because 18K would work for both buses, no need to use two different values). Conversely, a 1K5 resistor is the smallest value we could use without burning up the I2C pins of our devices.
Can a I2C interface take multiple serial devices?
Both i2c-interface real time clock module and 2×16 LCD module use the same pin A4 (SDA) and A5 (SCL) on Arduino Uno. After hours of searching on the net the i2c bus can actually take many serial devices. This is possible because each device has its own unique address.