ATXMEGA128B1_14 Datasheet, PDF (84/142 Pages) ATMEL Corporation – 8/16-bit Atmel XMEGA B1 Microcontroller

36.14.6 External Clock Characteristics
Figure 36-3. External Clock Drive Waveform
t_CH
t_CH
t_CR
t_CF
V_IH1
V_IL1
t_CL
t_CK
Table 36-25. External clock used as system clock without prescaling.
Symbol Parameter
1/t_CK Clock frequency⁽¹⁾
t_CK
Clock period
t_CH
Clock high time
t_CL
Clock low time
t_CR
Rise time (for maximum frequency)
t_CF
Fall time (for maximum frequency)
t_CK Change in period from one clock cycle to the next
Condition
V_CC = 1.6 - 1.8V
V_CC = 2.7 - 3.6V
V_CC = 1.6 - 1.8V
V_CC = 2.7 - 3.6V
V_CC = 1.6 - 1.8V
V_CC = 2.7 - 3.6V
V_CC = 1.6 - 1.8V
V_CC = 2.7 - 3.6V
V_CC = 1.6 - 1.8V
V_CC = 2.7 - 3.6V
V_CC = 1.6 - 1.8V
V_CC = 2.7 - 3.6V
Min
Typ
Max Units
0
12
MHz
0
32
83.3
ns
31.5
30.0
ns
12.5
30.0
ns
12.5
10
ns
3
10
ns
3
10
%
Note:
1. The maximum frequency vs. supply voltage is linear between 1.8V and 2.7V, and the same applies for all other parameters with supply voltage conditions.
XMEGA B1 [DATASHEET] 84
Atmel-8330F-AVR-ATxmega64B1-128B1_datasheet–AVR–02/2014