Get value of CPU CCOUNT register which contains CPU ticks. The register is 32-bit and rolls over.
Converting the register's CPU ticks to us is done by dividing it to 80 or 160 (CPU80/CPU160) i.e. `tmr.ccount() / node.getcpufreq()`.
Register arithmetic works without need to account for roll over, unlike `tmr.now()`. Because of same reason when CCOUNT is having its 32nd bit set, it appears in Lua as negative number.
#### Syntax
`tmr.ccount()`
#### Returns
The current value of CCOUNT register.
#### Example
```lua
functiontimeIt(fnc,cnt)
localfunctionloopIt(f2)
localt0=tmr.ccount()
fori=1,cntdo
f2()
end
localt1=tmr.ccount()
returnmath.ceil((t1-t0)/cnt)
end
assert(type(fnc)=="function","function to test missing")