What crystal do i use for 3,3volt 8mhz

Other Hardware 3rd Party Boards
1

Hi,

I'm trying to make a board work on 3,3v and an 8mhz crystal with my chip from an uno board. As I didn't got my board working. I got back tot my breadboard.

Turns out my 8 mhz crystal does not work. (will not upload sketches) I got the TXC - 9B-8.000MAAJ-B - XTAL, 8.000MHZ, 18PF, HC-49S from farnell: #1842268.

Why doesn't this work, what crystal from farnell europe will work?

Can anyone help me?

Thanks!

2

Campagne:
Hi,

I'm trying to make a board work on 3,3v and an 8mhz crystal. As I didn't got my board working. I got back tot my breadboard.

Turns out my 8 mhz crystal does not work. (will not upload sketches) I got the TXC - 9B-8.000MAAJ-B - XTAL, 8.000MHZ, 18PF, HC-49S from farnell: #1842268.

Why doesn't this work, what crystal from farnell europe will work?

Can anyone help me?

Thanks!

Have you burned the proper fuse byte values to tell the chip to utilize the external crystal? What kind of AVR chip are you using?
Are you using the two proper size 'padding' capacitors with the crystal?

3

Have you burned the proper fuse byte values to tell the chip to utilize the external crystal?

How do i do this? What does that mean? Can you direct me to a good post or tutorial about this?

I'm using my arduino uno as isp. And im trying to make a ATMEGA328-PU work on 3,3v with 8mhz crystal.
I got two 22pf caps on the crystal terminals...

When working on 5 volt with 16mhz, I just bootloaded the chip and could start programming.

Thanks for any help.

4

If you select the board type as Pro mini (3,3v, 8mhz) as the board type and then hit burn bootloader that will set the fuse bytes for using an external 8 mhz crystal and the bootloader will operate correctly at 8mhz if you use a USB serial converter chip/cable/module for uploading. If you use just ISP to upload programs there will be no bootloader (it will be erased the first time you perform a upload sketch using programmer option) but you still should use the same pro-mini 3.3v/8MHz board selection so the the sketch to be compiled will know the proper clock speed for functions like delay() etc.