XL1 and XL2, XC1 and XC2

[stone.xiang]

Hi,

I want to know which pin is signal input and which pin is signal out put for  XL1 and XL2, XC1 and XC2.

The document just say they are analog inpu, no ohter introduction.

 

Thanks.

[twihtronics]

usually xtal1 (xl1) is connected to the input of an internal amplifier and xtal2 (xl2) is connected to the output of that amplifier circuit. Fortunately if you are using a crystal oscillator the orientation should not matter as it should work either way. If you are trying to use a clock source then you will need to connect to xl1. Take a look at page 101 on the product spec. Or the clock section of the product spec.

As you see in the above image XL1 input of the amplifier and Xl2 is output. Note the actual crystal has no orientation, so it can be placed either pin 1 to XL1 or pin 1 to XL2. The important part is to choose the correct C1/C2 components so the crystal resonates correctly. 

[stone.xiang]

thanks!

How about XC1 and XC2?  Which is input and which is ouput?

[twihtronics]

The circuit should be the same. XC1 is connected to the input of the inverting amplifier and XC2 is connected to the output. A general rule of thumb is X1 is input while X2 is output of the internal circuit.