For those interested in 'A' versions: I have stuffed ~8000 ATMega16 onto boards, or at least they were supposed to be ATMega16. In reality, even though the package says 16, they are 16A (the die shrink). Decapsulation confirms this, and Atmel confirms this. They were acquired through a reputable distributor, and the distributor is willing to help, so no blame there. They are supposed to be functionally identical to non-A, only on the 16A I have, 95% of them can not run without capacitor on AREF. Atmel confirms that they should be able to do so. This is what AREF looks like when switching from AVCC to internal 2.56V: http://n1.taur.dk/avrfreaks/s16a9.png neat, huh? Is anybody else seeing this? These were dc 1036, on boards with awesomely clean power supplies and decoupling. /Kasper Pedersen (KKP) And to add a conspiracy theory, THIS is why avrfreaks is down ;-)
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ATMega16A - AREF oscillating
2011-07-18 by kkpdk