Hello everyone,

I am contemplating having a go at implementing some form of digit cross 
fade effect of which I have zero experience, knowledge or understanding and 
I am hoping that someone could point me in the right direction.

I can see that there are established designs using HV5622 drivers which are 
capable of cross fading digits that change and I'd like to implement this 
myself.

I already use the blanking signal via a PWM signal to perform overall 
fading of the display (all tubes) though the trick must be maintaining full 
brightness for the digits that stay static whilst varying the brightness of 
the incoming and outgoing changing digits.

If this assumption is correct then I'm also going to assume that, even for 
the digits that remain static - they cannot be on all the time and there 
must be some 'off' time during which the changing digits can be faded. 

This all makes use of the persistence of vision thing that makes us think 
that the display is static.

If I'm still on the right track then I am guessing that there will be a 
sufficient 'off' time for the static digits to allow the fading digits 
(incoming and outgoing) to be presented at varying degrees of 'brightness'.

In a very rough pseudo code kind of thing:


:start of transition
Set shift register for static digits, turn all digits on, wait long enough 
for the 'full display' effect', turn all digits off
Set Shift register for outgoing digits only, turn on, wait long enough 
though reduce this period during the course of the transition, turn all 
digits off.
Set Shift register for the incoming digits only, turn on, wait long enough 
for the digits to start appearing and increase this period during the 
course of the transition, turn all digits off
Loop back to start until transition is complete

Am I anywhere near close with this?

Is there any published method?

I have yet to point my scope at a working clock to investigate this further 
- I currently have an inherent reluctance to do this following a recent 
episode of clumsy probing resulting in the premature expiration of the 
device that I was investigating :-(

It's really just the concept that I would like to fully grasp, I find that 
I can stare at sample code segments all day long and not make any 
meaningful progress, though code segments are most welcome.

All pointers gleefully received.

Richard

-- 
You received this message because you are subscribed to the Google Groups 
"neonixie-l" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to [email protected].
To view this discussion on the web, visit 
https://groups.google.com/d/msgid/neonixie-l/ae272aa4-9f94-446b-87c4-506135ad66a6%40googlegroups.com.

Reply via email to