Who said ATtiny10 is "brain dead" ? In its data sheet we cannot find word I2C but we can add function as same as LED blinking. In addition, ATtiny10 has one 16 bit timer which can be driven by external clock. Naturally it will work as "frequency counter!" Here we have!

Actually I had some accumulation of AVR assembly for these two months and this code is easily written after I2C bitbang completion.This is quick coding and not optimised but as same as before dirty code is released on github.

My code occupies on flash as,

"ATtiny10" memory use summary [bytes]:
Segment   Begin    End      Code   Data   Used    Size   Use%
--------------------------------------------------------
[.cseg] 0x000000 0x000304    772      0    772    1024  
[.dseg] 0x000040 0x000060      0      0      0      32  
[.eseg] 0x000000 0x000000      0      0      0       0  

Actual operation can be found in the following movie... Have fun and let us believe "Tiny" power!