ST72T631K4M1 STMicroelectronics, ST72T631K4M1 Datasheet - Page 73

• Manufacturer Part Number: ST72T631K4M1
• Description: Microcontrollers (MCU) OTP EPROM 16K USB/SC
• Manufacturer: STMicroelectronics

Specifications of ST72T631K4M1

• Data Bus Width: 8 bit
• Program Memory Type: EPROM
• Program Memory Size: 16 KB
• Data Ram Size: 512 B
• Interface Type: I2C, SCI, USB
• Maximum Clock Frequency: 8 MHz
• Number Of Programmable I/os: 19
• Number Of Timers: 2
• Operating Supply Voltage: 4 V to 5.5 V
• Maximum Operating Temperature: + 70 C
• Mounting Style: SMD/SMT
• Package / Case: SO-34
• Minimum Operating Temperature: 0 C
• On-chip Adc: 8 bit
• Lead Free Status / Rohs Status: No

5.7 I²C BUS INTERFACE (I²C)
5.7.1 Introduction
The I²C Bus Interface serves as an interface be-
tween the microcontroller and the serial I²C bus. It
provides both multimaster and slave functions,
and controls all I²C bus-specific sequencing, pro-
tocol, arbitration and timing. It supports fast I²C
mode (400 kHz).
5.7.2 Main Features
I²C Master Features:
I²C Slave Features:
5.7.3 General Description
In addition to receiving and transmitting data, this
interface converts it from serial to parallel format
and vice versa, using either an interrupt or polled
Figure 38. I²C BUS Protocol
Parallel-bus/I²C protocol converter
Multi-master capability
7-bit Addressing
Transmitter/Receiver flag
End-of-byte transmission flag
Transfer problem detection
Clock generation
I²C bus busy flag
Arbitration Lost Flag
End of byte transmission flag
Transmitter/Receiver Flag
Start bit detection flag
Start and Stop generation
Stop bit detection
I²C bus busy flag
Detection of misplaced start or stop condition
Programmable I²C Address detection
Transfer problem detection
End-of-byte transmission flag
Transmitter/Receiver flag
SCL
SDA
CONDITION
START
MSB
1
2
handshake. The interrupts are enabled or disabled
by software. The interface is connected to the I²C
bus by a data pin (SDAI) and by a clock pin (SCLI).
It can be connected both with a standard I²C bus
and a Fast I²C bus. This selection is made by soft-
ware.
Mode Selection
The interface can operate in the four following
modes:
– Slave transmitter/receiver
– Master transmitter/receiver
By default, it operates in slave mode.
The interface automatically switches from slave to
master after it generates a START condition and
from master to slave in case of arbitration loss or a
STOP generation, this allows Multi-Master capa-
bility.
Communication Flow
In Master mode, it initiates a data transfer and
generates the clock signal. A serial data transfer
always begins with a start condition and ends with
a stop condition. Both start and stop conditions are
generated in master mode by software.
In Slave mode, the interface is capable of recog-
nising its own address (7-bit), and the General Call
address. The General Call address detection may
be enabled or disabled by software.
Data and addresses are transferred as 8-bit bytes,
MSB first. The first byte following the start condi-
tion is the address byte; it is always transmitted in
Master mode.
A 9th clock pulse follows the 8 clock cycles of a
byte transfer, during which the receiver must send
an acknowledge bit to the transmitter. Refer to
ure
1.
8
ACK
9
CONDITION
STOP
VR02119B
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