Re: [lcd4linux] GPO circuitry

[Michael R. <re...@eu...>]

Hi Aragon,

> All these components that I could add have a propogation delay just like the
> 44780 has propogation delays.  How granular can signals be timed on a
> parallel port?

Well, that depends on the speed of your computer. For small delays I 
have to use busy-waiting, and I do use the RDTSC command (Read Time 
Stamp Counter) from the i686. This gives you a theoretical resolution of 
1/(CPU clock frequency), which is 1 nanosecond at 1 GHz.

But this is very theoretical :-) There are things like signals, 
interrupts, syscall latency, ....

I do use delays in the range of 20-50 nsec, but always as a "minimum delay".


bye, Michael

-- 
Michael Reinelt                                   Tel: +43 676 3079941
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