AVR-Chat

Hello All,

I just want to have feedback about some tests made by me. I have been working with ATMEGA64L. ATMEGA64L-8AU (Vdd=2.7V to 5.5V) works with 8MHz external crystal oscillator as stated in the specification. 

Since I am using SD card and I am extracting data from SD card and send it to the TFT display. I am facing the problem of speed, as with 8MHz crystal oscillator, I found that out the data to be displayed on the TFT screen is very slow. So, I decided to use ATMEGA64-16AU with 16MHz crystal oscillator but after looking at the datasheet found out that ATMEGA64-16AU micro-controller works with the 4.5V to 5.5V Vdd range and for this reason I cant use the controller because SD card works with 3.3V Vdd. 

Then I use the same micro-controller ATMEGA64L-8AU and use the 16MHz external oscillator crystal. I found out that the data to be displayed on the TFT is pretty fast but the problem is that it is beyond the specification because ATMEGA64L-8AU (Vdd=2.7V to 5.5V) can only work with 8Mhz external crystal oscillator.

Could somebody comment what are the pros and cons of using ATMEGA64L-8AU with 16MHz oscillator crystal. 

Best Regards,
Farhan Ahmad