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

Just one frequently reads a info sheet in just one of two approaches. The to start with is to acquire just about every spec at encounter price, figuring that the engineers have taken almost everything into account and presented each variety as the complete limit that will avoid the Magic Smoke from escaping. The other way is to toss out the details sheet and just try what ever you want, figuring that the engineers played it as securely as attainable.

The latter situation would seem to have been the determination guiding pushing an ATtiny way, WAY further than what the spec sheet states is probable. According to [SM6VFZ], the specs on the ATtiny817 display that the 12-little bit timer/counter D (TCD) should be constrained to a measly 32 MHz utmost frequency, higher than which just one is meant to employ the counter’s internal prescaler. But by employing a 10-MHz precision frequency generator as an exterior clock, [SM6VFZ] identified that inputs up to slightly earlier mentioned 151 MHz ended up countable with 1-Hz precision. Previously mentioned that place, things started to drift, but that’s nonetheless quite fantastic functionality from one thing cobbled together on an eval board in a decidedly suboptimal way.

We’d consider this end result could lead to some attention-grabbing tasks, given that the undocumented restrict for this timer puts it nicely within vary of multiple novice radio allocations. Even if it does not demonstrate valuable, that’s Okay — just viewing how much factors can be pushed is awesome as well. And it’s not like this is the initially time we have caught [SM6VFZ] persuading an ATtiny to do unusual things, either.