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16 MHz => 8 MHz for EMUPS4
Posted: Mon Feb 01, 2016 11:55 am
by mstrVLT
I need set F_CPU = 8000000 (8 MHz) for EMUPS4
Will it work? What do you think?
Maybe need change USART_BAUDRATE 500000 to ...
Re: 16 MHz => 8 MHz for EMUPS4
Posted: Mon Feb 01, 2016 12:05 pm
by Matlo
Instead of running the Teensy at 3.3V, you should shift the voltage using a simple voltage divider.
http://gimx.fr/forum/viewtopic.php?p=4485#p4485
Re: 16 MHz => 8 MHz for EMUPS4
Posted: Tue Feb 02, 2016 8:30 am
by mstrVLT
in datasheet AT90USB1286 (teensy++ 2.0)

Baudrate 0% error on 3V
I think it's possible, i try. This way is better and easy than add divider or revrite firmware to arm
Re: 16 MHz => 8 MHz for EMUPS4
Posted: Tue Feb 02, 2016 9:10 am
by Matlo
At 8MHz the AVR will execute twice less instructions per second.
It may still work, but you may also get timing issues.
Using a voltage divider is trouble-free.