
Rev. 3.00, 03/04, page 496 of 830
4. SCL and SDA input is sampled in synchronization with the internal clock. The AC timing
therefore depends on the system clock cycle t
cyc
, as shown in section 25, Electrical
Characteristics. Note that the I
system clock frequency of less than 5 MHz.
5. The I
speed mode). In master mode, the I
one bit at a time during communication. If t
sr
(the time for SCL to go from low to V
IH
) exceeds
the time determined by the input clock of the I
extended. The SCL rise time is determined by the pull-up resistance and load capacitance of
the SCL line. To insure proper operation at the set transfer rate, adjust the pull-up resistance
and load capacitance so that the SCL rise time does not exceed the values given in table 15.12.
Table 15.12 Permissible SCL Rise Time (t
sr
) Values
2
C bus interface AC timing specification will not be met with a
2
C bus interface specification for the SCL rise time t
sr
is 1000 ns or less (300 ns for high-
2
C bus interface monitors the SCL line and synchronizes
2
C bus interface, the high period of SCL is
Time Indication [ns]
TCSS IICXn
t
cyc
Indi-
cation
I
Spe-
cifica-
tion
(Max.)
2
C Bus
φ
= 5
MHz
φ
= 8
MHz
φ
= 10
MHz
φ
= 16
MHz
φ
= 20
MHz
φ
= 25
MHz
φ
= 33
MHz
Standard
mode
1000
1000
937
750
468
375
300
227
0
7.5 t
cyc
High-
speed
mode
300
300
300
300
300
300
300
227
0
1
Standard
mode
1000
1000
1000
1000
1000
875
700
530
1
0
17.5 t
cyc
High-
speed
mode
300
300
300
300
300
300
300
300
Standard
mode
1000
1000
1000
1000
1000
1000
1000
1000
1
1
37.5 t
cyc
High-
speed
mode
300
300
300
300
300
300
300
300
Note: n = 0 to 5
6. The I
and 300 ns. The I
table 15.11. However, because of the rise and fall times, the I
may not be satisfied at the maximum transfer rate. Table 15.13 shows output timing
calculations for different operating frequencies, including the worst-case influence of rise and
fall times.
2
C bus interface specifications for the SCL and SDA rise and fall times are under 1000 ns
2
C bus interface SCL and SDA output timing is prescribed by t
cyc
, as shown in
2
C bus interface specifications