
212
8008H–AVR–04/11
ATtiny48/88
22.8
Two-Wire Serial Interface Characteristics
The following data is based on simulations and characterisations. Parameters listed in
Table 22-7 are not tested in produc-
Notes:
1. f
CK = CPU clock frequency.
Figure 22-3. Two-Wire Serial Bus Timing
Table 22-7.
Two-Wire Serial Interface Characteristics
Symbol
Parameter
Condition
Min
Max
Unit
V
IL
Input Low voltage
-0.5
0.3 V
CC
V
VIH
Input High voltage
0.7 VCC
VCC + 0.5
V
VHYS
Hysteresis of Schmitt-trigger inputs
VCC
2.7V
0.05 VCC
–
V
CC < 2.7V
0
VOL
Output Low voltage
3mA sink current
0
0.4
V
tSP
Spikes suppressed by input filter
0
50
ns
f
SCL
f
CK > max(16fSCL, 250kHz)
0
400
kHz
tHD:STA
Hold time (repeated) START Condition
0.6
–
s
tLOW
Low period of SCL clock
1.3
–
s
t
HIGH
High period of SCL clock
0.6
–
s
tSU:STA
Set-up time for repeated START condition
0.6
–
s
tHD:DAT
Data hold time
00.9
s
t
SU:DAT
Data setup time
100
–
ns
tSU:STO
Setup time for STOP condition
0.6
–
s
t
BUF
Bus free time between STOP and START condition
1.3
–
s
tSU;STA
tLOW
tHIGH
tLOW
tof
tHD;STA
tHD;DAT
tSU;DAT
tSU;STO
tBUF
SCL
SDA
tr