atmega32u4-16mu ATMEL Corporation, atmega32u4-16mu Datasheet - Page 401

• Manufacturer Part Number: atmega32u4-16mu
• Description: Atmega32u4 8-bit Avr Microcontroller With 32k Bytes Of Isp Flash And Usb Controller
• Manufacturer: ATMEL Corporation

Table 30-2.
Notes:
7766A–AVR–03/08
Symbol
t
t
t
t
t
t
HIGH
SU;STA
HD;DAT
SU;DAT
SU;STO
BUF
1. In ATmega32U4, this parameter is characterized and not 100% tested.
2. Required only for f
3. C
4. f
5. This requirement applies to all ATmega32U4 2-wire Serial Interface operation. Other devices connected to the 2-wire Serial
6. The actual low period generated by the ATmega32U4 2-wire Serial Interface is (1/f
7. The actual low period generated by the ATmega32U4 2-wire Serial Interface is (1/f
Bus need only obey the general f
6 MHz for the low time requirement to be strictly met at f
will not be strictly met for f
cate at full speed (400 kHz) with other ATmega32U4 devices, as well as any other device with a proper t
margin.
Parameter
High period of the SCL clock
Set-up time for a repeated START condition
Data hold time
Data setup time
Setup time for STOP condition
Bus free time between a STOP and START
condition
CK
b
= capacitance of one bus line in pF.
= CPU clock frequency
2-wire Serial Bus Requirements (Continued)
Figure 30-3. 2-wire Serial Bus Timing
SCL
SCL
SDA
> 100 kHz.
SCL
t
SU;STA
> 308 kHz when f
SCL
requirement.
t
HD;STA
CK
t
t
of
= 8 MHz. Still, ATmega32U4 devices connected to the bus may communi-
LOW
f
f
f
f
f
f
f
f
f
f
f
f
SCL
SCL
SCL
SCL
SCL
SCL
SCL
SCL
SCL
SCL
SCL
SCL
SCL
Condition
t
= 100 kHz.
HIGH
≤ 100 kHz
> 100 kHz
≤ 100 kHz
> 100 kHz
≤ 100 kHz
> 100 kHz
≤ 100 kHz
> 100 kHz
≤ 100 kHz
> 100 kHz
≤ 100 kHz
> 100 kHz
t
HD;DAT
t
LOW
t
SU;DAT
SCL
SCL
- 2/f
- 2/f
250
100
Min
4.0
0.6
4.7
0.6
4.0
0.6
4.7
1.3
0
0
CK
CK
), thus the low time requirement
), thus f
ATmega32U4
CK
t
SU;STO
must be greater than
t
r
LOW
3.45
Max
0.9
–
–
–
–
–
–
–
–
–
–
acceptance
t
BUF
Units
µs
µs
µs
µs
µs
µs
ns
ns
µs
µs
µs
µs
401