Atmel Xplained Pro Evaluation Kit for the ATSAMD21J18A Microcontroller ATSAMD21-XPRO ATSAMD21-XPRO Data Sheet

953

Atmel | SMART SAM D21 [DATASHEET]

Atmel-42181C–SAM-D21_Datasheet–07/2014

The following table describes the characteristics for the oscillator when a digital clock is applied on XIN32 pin.

 and the equation in 

 also applies to the 32kHz oscillator 

connection. The user must choose a crystal oscillator where the crystal load capacitance C

L

 is within the range given in 

the table. The exact value of C

L

 can be found in the crystal datasheet.

f

CPXIN32

XIN32 clock frequency

I

-

32.768

-

kHz

I

XIN32 clock duty cycle

I

-

50

-

%

f

OUT

Crystal oscillator frequency

I

-

32768

-

Hz

t

STARTUP

Startup time

ESR

XTAL

 = 39.9k

Ω, C

L

 = 12.5pF

-

28K

30K

cycles

C

L

Crystal load capacitance

I

-

-

12.5

pF

C

SHUNT

Crystal shunt capacitance

I

-

0.1

-

C

XIN32

Parasitic capacitor load

TQFP64/48/32 packages

-

3.1

-

C

XOUT32

Parasitic capacitor load

-

3.3

-

I

XOSC32K

Current consumption

-

1.22

2.19

µA

ESR

Crystal equivalent series 
resistance f=32.768kHz
Safety Factor = 3

C

L

=12.5pF 

-

-

141

k

Ω