HT85F2270 datasheet(177/226 Pages) HOLTEK

177 / 226 page

Rev. 1.00

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Standard 8051 8-Bit Flash MCU

HT85F2260/HT85F2270/HT85F2280

34 I2C Serial Interface

The I2C interface is used to communicate with external peripheral devices such as sensors,

EEPROM memory etc. Originally developed by Philips, it is a two line low speed serial interface

for synchronous serial data transfer. The advantage of only two lines for communication, relatively

simple communication protocol and the ability to accommodate multiple devices on the same bus

has made it an extremely popular interface type for many applications.

I2C Master Slave Bus Connection

I2C Interface Operation

The I2C serial interface is a two line serial interface. These lines are a serial data line, SDA, and

serial clock line, SCL. As many devices may be connected together on the same bus, their outputs

are both open drain types. For this reason it is necessary that external pull-high resistors are

connected to these outputs. Note that no chip select line exists, as each device on the I2C bus is

identified by a unique address which will be transmitted and received on the I2C bus.

When two devices communicate with each other on the bidirectional I2C bus, one is known as the

master device and one as the slave device. Both master and slave can transmit and receive data,

however, it is the master device that has overall control of the bus. The I2C meets the Philips I2C

bus specification and supports all transfer modes from and to the I2C bus.

When the I2C is in the master mode, a variable baud rate setup is available using the I2C clock

generator. The clock source is sourced from the system clock. The clock generator can be controlled

using the I2CLK register. The clock generator is suppressed when the I2C is in the slave mode.

I2C Interface Operation Flow

HT85F2270 bảng dữ liệu(PDF) 177 Page - Holtek Semiconductor Inc