PIC16F946
DS41265A-page 252
Preliminary
2005 Microchip Technology Inc.
TABLE 19-14: I2C BUS DATA REQUIREMENTS
Param.
No.
Symbol
Characteristic
Min
Max
Units
Conditions
100*
THIGH
Clock high time
100 kHz mode
4.0
—
μs
Device must operate at a
minimum of 1.5 MHz
400 kHz mode
0.6
—
μs
Device must operate at a
minimum of 10 MHz
SSP Module
1.5TCY
—
101*
TLOW
Clock low time
100 kHz mode
4.7
—
μs
Device must operate at a
minimum of 1.5 MHz
400 kHz mode
1.3
—
μs
Device must operate at a
minimum of 10 MHz
SSP Module
1.5TCY
—
102*
TR
SDA and SCL rise
time
100 kHz mode
—
1000
ns
400 kHz mode
20 + 0.1CB
300
ns
CB is specified to be from
10-400 pF
103*
TF
SDA and SCL fall
time
100 kHz mode
—
300
ns
400 kHz mode
20 + 0.1CB
300
ns
CB is specified to be from
10-400 pF
90*
TSU:STA
Start condition
setup time
100 kHz mode
4.7
—
μs
Only relevant for
Repeated Start condition
400 kHz mode
0.6
—
μs
91*
THD:STA
Start condition hold
time
100 kHz mode
4.0
—
μs
After this period the first
clock pulse is generated
400 kHz mode
0.6
—
μs
106*
THD:DAT
Data input hold time 100 kHz mode
0
—
ns
400 kHz mode
0
0.9
μs
107*
TSU:DAT
Data input setup
time
100 kHz mode
250
—
ns
(Note 2)
400 kHz mode
100
—
ns
92*
TSU:STO
Stop condition
setup time
100 kHz mode
4.7
—
μs
400 kHz mode
0.6
—
μs
109*
TAA
Output valid from
clock
100 kHz mode
—
3500
ns
(Note 1)
400 kHz mode
—
ns
110*
TBUF
Bus free time
100 kHz mode
4.7
—
μs
Time the bus must be free
before a new transmission
can start
400 kHz mode
1.3
—
μs
CB
Bus capacitive loading
—
400
pF
*
These parameters are characterized but not tested.
Note 1:
As a transmitter, the device must provide this internal minimum delay time to bridge the undefined region
(min. 300 ns) of the falling edge of SCL to avoid unintended generation of Start or Stop conditions.
2:
A Fast mode (400 kHz) I2C bus device can be used in a Standard mode (100 kHz) I2C bus system, but the
requirement TSU:DAT
≥ 250 ns must then be met. This will automatically be the case if the device does not
stretch the low period of the SCL signal. If such a device does stretch the low period of the SCL signal, it
must output the next data bit to the SDA line TR max. + TSU:DAT = 1000 + 250 = 1250 ns (according to the
Standard mode I2C bus specification), before the SCL line is released.