WS2811 and WS2812 One-Wire Communication Assembly Help

[Ioannis]

Richard, thanks for looking into this.

For 64 led's I think the timing for each frame is 3,84ms. Does it work with 2ms?

Anyway, you did a great job on this. Really fast!

Well, the AN implied, or at least I wanted to be that way, this solution would be fast enough for the MCU to do other tasks.

But as you tested, yes, seems there is not enough time.

I want to use this strips for a 60 led's (1m bar) for medical purposes and the timing is very strict.

Thanks,
Ioannis

[richard]

I may have measured that wrong, its more like 5mS now for 192 bytes


the spi takes 25uS per byte and there is a 5us gap between bytes as is

I think the gap between bytes needs to be less than 50uS

so an isr has 60us to get in do something and get out again

conversely an asm isr could feed the spi buffer every 60uS or so

[richard]

just for a joke I upped the osc to 32mHz ,
it still works , its less than 3mS now for 192 bytes
these things aren't that fussy

[richard]

just remembered de morgan equivalents , have not done Boolean algebra since ttl was in vogue

[Ioannis]

It seems that the chips WS2811 are quite tolerant on the timing specs.

Ioannis

[mark_s]

Did you guys see this example/thread?

http://www.picbasic.co.uk/forum/showthread.php?t=19597

[richard]

Did you guys see this example/thread?

indeed . the point of my posts are to demonstrate tight loop routines that achieve the same task without all that spaghetti code


here is an interrupt driven version of the clc method using linear sram memory access to facilitate a 240 byte buffer on a pic16