Rev. 1.0, 02/00, page 512 of 1141
Table 23.7
I
2
C Bus Timing (with Maximum Influence of t
Sr
/t
Sf
)
Time Indication (at Maximum Transfer Rate) [ns]
Item
t
cyc
Indication
t
Sr
/t
Sf
Influence
(Max.)
I
2
C Bus
Specification
(Min.)
φφφφ
= 8 MHz
φφφφ
= 10 MHz
Normal mode
−
1000
4000
←
←
t
SCLHO
0.5t
SCLO
(-t
Sr
)
High-speed
mode
−
300
600
←
←
Normal mode
−
250
4700
←
←
t
SCLLO
0.5t
SCLO
(-t
Sf
)
High-speed
mode
−
250
1300
←
←
Normal mode
−
1000
4700
3875
*1
3900
*1
t
BUFO
0.5t
SCLO
-1t
cyc
(-t
Sr
)
High-speed
mode
−
300
1300
825
*1
850
*1
Normal mode
−
250
4000
4625
4650
t
STAHO
0.5t
SCLO
-1t
cyc
(-t
Sf
)
High-speed
mode
−
250
600
875
900
Normal mode
−
1000
4700
9000
9000
t
STASO
1t
SCLO
(-t
Sr
)
High-speed
mode
−
300
600
2200
2200
Normal mode
−
1000
4000
4250
4200
t
STOSO
0.5t
SCLO
+2t
cyc
(-t
Sr
)
High-speed
mode
−
300
600
1200
1150
Normal mode
−
1000
250
3325
3400
t
SDASO
(master)
1t
SCLLO
*
3
-3t
cyc
(-t
Sr
)
High-speed
mode
−
300
100
625
700
Normal mode
−
1000
250
2200
2500
t
SDASO
(slave)
1t
SCLL
*
3
-12t
cyc
*
2
(-t
Sr
)
High-speed
mode
−
300
100
−
500
*1
−
200
*1
Normal mode
0
0
375
300
t
SDAHO
3t
cyc
High-speed
mode
0
0
↑
↑
Notes: 1. Does not meet the I
2
C bus interface specification. Remedial action such as the
following is necessary: (a) secure a start/stop condition issuance interval; (b) adjust the
rise and fall times by means of a pull-up resistor and capacitive load; (c) reduce the
transfer rate; (d) select slave devices whose input timing permits this output timing.
The values in the above table will vary depending on the settings of the IICX bit and bits
CKS0 to CKS2. Depending on the frequency it may not be possible to achieve the
maximum transfer rate; therefore, whether or not the I
2
C bus interface specifications are
met must be determined in accordance with the actual setting conditions.
2. Value when the IICX bit is set to 1. When the IICX bit is cleared to 0, the value is (t
SCLL
-
6t
cyc
).
3. Calculated using the I
2
C bus specification values (standard mode: 4700 ns min.; high-
speed mode: 1300 ns min.).