ATXMEGA256A3BU Datasheet, PDF (84/143 Pages) ATMEL Corporation – 8/16-bit Atmel XMEGA A3BUMicrocontroller

Table 37-29. External clock with prescaler ⁽¹⁾for system clock.
Symbol
1/t_CK
t_CK
t_CH
t_CL
t_CR
t_CF
t_CK
Parameter
Clock Frequency ⁽²⁾
Clock Period
Clock High Time
Clock Low Time
Rise Time (for maximum frequency)
Fall Time (for maximum frequency)
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.
0
0
11
7
4.5
2.4
4.5
2.4
Typ.
Max.
90
142
Units
MHz
ns
ns
ns
1.5
ns
1.0
1.5
ns
1.0
10
%
Notes:
1. System Clock Prescalers must be set so that maximum CPU clock frequency for device is not exceeded.
2. The maximum frequency vs. supply voltage is linear between 1.6V and 2.7V, and the same applies for all other parameters with supply voltage conditions.
37.15.7 External 16MHz crystal oscillator and XOSC characteristics
Table 37-30. External 16MHz crystal oscillator and XOSC characteristics.
Symbol Parameter
Cycle to cycle jitter
Long term jitter
Frequency error
Duty cycle
Condition
XOSCPWR=0
XOSCPWR=1
XOSCPWR=0
XOSCPWR=1
XOSCPWR=0
XOSCPWR=1
XOSCPWR=0
XOSCPWR=1
FRQRANGE=0
FRQRANGE=1, 2, or 3
FRQRANGE=0
FRQRANGE=1, 2, or 3
FRQRANGE=0
FRQRANGE=1
FRQRANGE=2 or 3
FRQRANGE=0
FRQRANGE=1
FRQRANGE=2 or 3
Min.
Typ.
<10
<1
<1
<6
<0.5
<0.5
<0.1
<0.05
<0.005
<0.005
40
42
45
48
Max.
Units
ns
%
XMEGA A3BU [DATASHEET]
84
8362F–AVR–02/2013