#Free mplab xc8 verify code internet connection serial
It’s faster than asynchronous serial allowing large quantities of data to be transferred quickly but it slower than the SPI.This communication can support a maximum of 112 devices on the bus (The specification declares that 128 devices can be connected to the I 2C bus, but it also defines 16 reserved addresses) connected in a simple way by using only two valuable I/O pins. This time only two pins are used for data transmission, One for DATA: the SDA (Serial Data) and the other for CLOCK: the SCL (Serial Clock) pins. Similar to serial communication in SPI mode, data transfer in I2C mode is synchronous and bidirectional.
these devices (usually smart devices) can be memories modules like 24AA01 1Kb serial EEPROM, temperature sensors like the TC74, real-time clocks like the DS1307, DACs, ADCs, Input/Output expanders etc. I☬ bus is suitable when the microcontroller and a device which the microcontroller should exchange data with are in close proximity like preferably on the same PCB. Figure 2 below shows how the two pull up resistors (Rp) are connected.įigure 2: Pull-up resistors connected to I☬ bus
If the resistors are missing, the SCL and SDA lines will always be low nearly 0 volts and the I2C bus will not work. The value of the resistors is not really critical anything from 1k8 to 47k can be used, their values depend on the length of the bus line. You only need one set of pull-up resistors for the whole I2C bus, not for each device, as illustrated above. One resistor from the SCL line to the 5V line and another from the SDA line to the 5V line. For the line to be able to go high you must provide pull-up resistors to the 5V supply. This basically means that the chip can drive its output low, but it cannot drive it high. In our illustration, the first device with address 1 is a digital temperature sensor, the second one is a real time clock and the third one is a serial LCD display and the bus could carry on even more devices.Ĭommunication takes place from the master (PIC) to the individual selected slave only as shown in this illustration, the master sends data to the slave address 2 only.įigure 1: Slave devices connected to PIC with I☬ busīoth SCL and SDA lines are “open drain” drivers. The devices don’t have to be identical as long as they support I☬ protocol. Figure 1 below demonstrates how many devices can be connected with this simple two wire systems using only two pins of the microcontroller. I2C enables communication between electronic components or IC to IC. I2C has become one of the most common serial communication protocols in electronics. I☬ is sometimes called Two Wire Interface. I☬ (pronounced I-squared-C) created by Philips Semiconductors for use in communication of peripheral devices within a TV-set and commonly written as ‘I2C’ stands for Inter-Integrated Circuit and allows communication of data between I2C devices over two wires. Watch the Video Tutorial: Introduction to I 2C
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