PCF8573 Ver la hoja de datos (PDF) - Philips Electronics

Número de pieza

componentes Descripción

Lista de partido

PCF8573

Clock/calendar with serial I/O

Philips Electronics 

Philips Semiconductors

Clock/calendar with serial I/O

Product specification

PCF8573

8 CHARACTERISTICS OF THE I2C-BUS

The I2C-bus is for 2-way, 2-line communication between different ICs or modules. The two lines are a serial data line

(SDA) and a serial clock line (SCL). Both lines must be connected to a positive supply via a pull-up resistor when

connected to the output stages of a device. Data transfer may be initiated only when the bus is not busy.

8.1 Bit transfer

See Fig.4. One data bit is transferred during each clock pulse. The data on the SDA line must remain stable during the

HIGH period of the clock pulse as changes in the data line at this time will be interpreted as control signals.

handbook, full pagewidth

SDA

SCL

data line

stable;

data valid

change

of data

allowed

MBC621

Fig.4 Bit transfer.

8.2 Start and stop conditions

Refer to Fig.5. Both data and clock lines remain HIGH when the bus is not busy. A HIGH-to-LOW transition of the data

line, while the clock is HIGH is defined as the start condition (S). A LOW-to-HIGH transition of the data line while the

clock is HIGH is defined as the stop condition (P).

handbook, full pagewidth

SDA

SDA

SCL

S

START condition

SCL

P

STOP condition

MBC622

Fig.5 Definition of start and stop conditions.

2003 Jan 27

7

Share Link: