March 11, 2013
about a year ago
It’s not as bad as that I think, you should be able to get 12MHz comfortably.
Section 29.3 (“Speed Grades”) of the ATmel datasheet “Atmel 8-bit Microcontroller with 4/8/16/32KBytes
In-System Programmable Flash” states that the Maximum Frequency is linear across 2 intervals: between (1.8v=4MHz, 2.7v=10MHz) and between (2.7v=10MHz, 4.5v=20MHz).
This means that 3.3v implies a Maximum Frequency of 13.33MHz.
So I don’t see why we are not running at (say) 12MHz instead of 16MHz - apart from one having to do a relatively-straightforward patch to the NewSoftSerial library, as detailed here: http://wiblocks.luciani.org/docs/app-notes/software-serial.html. I run at 3.3v and 12MHz, using optiboot recompiled for that speed as the bootloader and everything works very well.
Food for thought if you are looking for a new version? I know intrinsic support in Arduino IDE is a little smoother for 8MHz but getting 50% more cycles is not to be sniffed at.
about 2 years ago
Worked first time and got sound levels centered around 127 on a 3.3V board as expected.
Managed to feed output through to a piezo as well.
Then I got “clever” and played with feedback, which seems to have rendered it dead as a dodo. However that is my own fault and I have ordered two replacements to much about with.
No public wish lists :(
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