Thursday, 6 November 2014

microcontroller - How do I deal with different XTAL pin capacitance when selecting XTAL and load capacitors


I'm trying to select a 32kHz crystal and appropriate load capacitors for Atmega48A MCU.


Atmega48A specifies different capacitances for Xtal1 and Xtal2 pins:


18pF for Xtal1 8pF for Xtal2


The datasheet says: "The capacitance (Ce+Ci) needed at each TOSC pin can be calculated by using:C = 2 * CL – Cs" Where CL is load capacitance specified for the crystal and Cs is stray capacitance.


Can I assume that each pin has (18+8)/2=13pF of capacitance? Can I select a 8pF crystal and use it without external load caps assuming ~3pF of stray capacitance?




-

No comments:

Post a Comment

Subscribe to: Post Comments (Atom)

arduino - Can I use TI's cc2541 BLE as micro controller to perform operations/ processing instead of ATmega328P AU to save cost?

I am using arduino pro mini (which contains Atmega328p AU ) along with cc2541(HM-10) to process and transfer data over BLE to smartphone. I...