at94k40al ATMEL Corporation, at94k40al Datasheet - Page 140

• Manufacturer Part Number: at94k40al
• Description: At94kal Series Field Programmable System Level Integrated Circuit
• Manufacturer: ATMEL Corporation

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140
2-wire Serial Interface (Byte Oriented)
AT94KAL Series FPSLIC
The 2-wire Serial Bus is a bi-directional two-wire serial communication standard. It is designed
primarily for simple but efficient integrated circuit (IC) control. The system is comprised of two
lines, SCL (Serial Clock) and SDA (Serial Data) that carry information between the ICs con-
nected to them. Various communication configurations can be designed using this bus.
Figure 4-45
can be Master or Slave.
Figure 4-45. 2-wire Serial Bus Configuration
The 2-wire Serial Interface provides a serial interface that meets the 2-wire Serial Bus specifica-
tion and supports Master/Slave and Transmitter/Receiver operation at up to 400 kHz bus clock
rate. The 2-wire Serial Interface has hardware support for the 7-bit addressing, but is easily
extended to 10-bit addressing format in software. When operating in 2-wire Serial mode, i.e.,
when TWEN is set, a glitch filter is enabled for the input signals from the pins SCL and SDA, and
the output from these pins are slew-rate controlled. The 2-wire Serial Interface is byte oriented.
The operation of the serial 2-wire Serial Bus is shown as a pulse diagram in
ing the START and STOP conditions and generation of ACK signal by the bus receiver.
Figure 4-46. 2-wire Serial Bus Timing Diagram
The block diagram of the 2-wire Serial Bus interface is shown in
SDA
SCL
CONDITION
START
shows a typical 2-wire Serial Bus configuration. Any device connected to the bus
MSB
Device 1
1
2
Device 2
7
R/W
BIT
8
Device 3
ACK
9
FROM RECEIVER
ACKNOWLEDGE
.......
1
2
Device n
Figure
8
REPEATED START CONDITION
R1
4-47.
ACK
9
R2
Figure
STOP CONDITION
1138I–FPSLI–1/08
4-46, includ-
V
SCL
SDA
CC