To Turn An ATtiny817 Into A 150MHz Counter, First Throw Out The Spec Sheet

A person usually reads a information sheet in just one of two methods. The initial is to consider each individual spec at confront value, figuring that the engineers have taken every thing into account and presented each and every number as the complete limit that will protect against the Magic Smoke from escaping. The other way is to throw out the info sheet and just consider whatsoever you want, figuring that the engineers performed it as securely as achievable.

The latter case looks to have been the drive at the rear of pushing an ATtiny way, WAY further than what the spec sheet suggests is achievable. In accordance to [SM6VFZ], the specs on the ATtiny817 display that the 12-bit timer/counter D (TCD) should be limited to a measly 32 MHz greatest frequency, earlier mentioned which one particular is intended to make use of the counter’s interior prescaler. But by applying a 10-MHz precision frequency generator as an exterior clock, [SM6VFZ] identified that inputs up to somewhat higher than 151 MHz were being countable with 1-Hz precision. Previously mentioned that issue, issues started off to drift, but that’s nonetheless quite fantastic performance from one thing cobbled jointly on an eval board in a decidedly suboptimal way.

We’d think about this final result could guide to some fascinating projects, due to the fact the undocumented restrict for this timer places it well in just variety of several beginner radio allocations. Even if it doesn’t establish helpful, that is Ok — just looking at how much points can be pushed is cool much too. And it is not like this is the 1st time we have caught [SM6VFZ] persuading an ATtiny to do unconventional things, either.