
ST7265x
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COMMUNICATION INTERFACE CHARACTERISTICS (Cont’d)
13.11.2 I2C - Inter IC Control Interface
Subject to general operating conditions for VDD,
fOSC, and TA unless otherwise specified.
Refer to I/O port characteristics for more details on
the input/output alternate function characteristics
(SDAI and SCLI). The ST7 I2C interface meets the
requirements of the Standard I2C communication
protocol described in the following table.
Figure 102. Typical Application with I2C Bus and Timing Diagram 4)
Notes:
1. Data based on standard I2C protocol requirement, not tested in production.
2. The device must internally provide a hold time of at least 300ns for the SDA signal in order to bridge the undefined
region of the falling edge of SCL.
3. The maximum hold time of the START condition has only to be met if the interface does not stretch the low period of
SCL signal.
4. Measurement points are done at CMOS levels: 0.3xVDD and 0.7xVDD.
Symbol
Parameter
Standard mode I2C
Fast mode I2C
Unit
Min 1)
Max 1)
Min 1)
Max 1)
tw(SCLL)
SCL clock low time
4.7
1.3
s
tw(SCLH)
SCL clock high time
4.0
0.6
tsu(SDA)
SDA setup time
250
100
ns
th(SDA)
SDA data hold time
0 3)
0 2)
900 3)
tr(SDA)
tr(SCL)
SDA and SCL rise time
1000
20+0.1Cb
300
tf(SDA)
tf(SCL)
SDA and SCL fall time
300
20+0.1Cb
300
th(STA)
START condition hold time
4.0
0.6
s
tsu(STA)
Repeated START condition setup time
4.7
0.6
tsu(STO)
STOP condition setup time
4.0
0.6
ns
tw(STO:STA) STOP to START condition time (bus free)
4.7
1.3
ms
Cb
Capacitive load for each bus line
400
pF
REPEATED START
START
STOP
START
tf(SDA)
tr(SDA)
tsu(SDA)
th(SDA)
tf(SCK)
tr(SCK)
tw(SCKL)
tw(SCKH)
th(STA)
tsu(STO)
tsu(STA)
tw(STO:STA)
SDA
SCK
4.7k
SDAI
ST72XXX
SCLI
VDD
100
100
VDD
4.7k
I2CBUS