Datasheet

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362
ATmega640/V-1280/V-1281/V-2560/V-2561/V [DATASHEET]
2549Q–AVR–02/2014
Note: 1. In ATmega640/1280/1281/2560/2561, this parameter is characterized and not 100% tested.
2. Required only for f
SCL
> 100kHz.
3. C
b
= capacitance of one bus line in pF.
4. f
CK
= CPU clock frequency.
5. This requirement applies to all ATmega640/1280/1281/2560/2561 2-wire Serial Interface operation. Other devices
connected to the 2-wire Serial Bus need only obey the general f
SCL
requirement.
Table 31-7. 2-wire Serial Bus Requirements
Symbol Parameter Condition Min. Max. Units
VIL
Input Low-voltage -0.5 0.3 V
CC
V
VIH
Input High-voltage 0.7 V
CC
V
CC
+ 0.5
Vhys
(1)
Hysteresis of Schmitt Trigger Inputs 0.05 V
CC
(2)
VOL
(1)
Output Low-voltage 3mA sink current 0 0.4
tr
(1)
Rise Time for both SDA and SCL
20 +
0.1C
b
(3)(2)
300
ns
tof
(1)
Output Fall Time from V
IHmin
to V
ILmax
10pF < C
b
< 400pF
(3)
20 +
0.1C
b
(3)(2)
250
tSP
(1)
Spikes Suppressed by Input Filter 0 50
(2)
I
i
Input Current each I/O Pin 0.1V
CC
< V
i
< 0.9V
CC
-10 10 µA
C
i
(1)
Capacitance for each I/O Pin 10 pF
f
SCL
SCL Clock Frequency
f
CK
(4)
> max(16f
SCL
,
250kHz)
(5)
0 400 kHz
Rp Value of Pull-up resistor
f
SCL
100kHz
f
SCL
> 100kHz
t
HD;STA
Hold Time (repeated) START Condition
f
SCL
100kHz 4.0
µs
f
SCL
> 100kHz 0.6
t
LOW
Low Period of the SCL Clock
f
SCL
100kHz
(6)
4.7
f
SCL
> 100kHz
(7)
1.3
t
HIGH
High period of the SCL clock
f
SCL
100kHz 4.0
f
SCL
> 100kHz 0.6
t
SU;STA
Set-up time for a repeated START condition
f
SCL
100kHz 4.7
f
SCL
> 100kHz 0.6
t
HD;DAT
Data hold time
f
SCL
100kHz 0 3.45
f
SCL
> 100kHz 0 0.9
t
SU;DAT
Data setup time
f
SCL
100kHz 250
f
SCL
> 100kHz 100
t
SU;STO
Setup time for STOP condition
f
SCL
100kHz 4.0
f
SCL
> 100kHz 0.6
t
BUF
Bus free time between a STOP and START
condition
f
SCL
100kHz 4.7
f
SCL
> 100kHz 1.3
V
CC
0.4V
3mA
----------------------------
1000ns
C
b
-------------------
V
CC
0.4V
3mA
----------------------------
300 ns
C
b
------------------