Forgot to mention. I don't want to enable the end user to log in to root to setup the wifi during the first start setup on wifi setup page. To enable the end user to use above method, the wifi should already be setup and the computer connected to the omega AP
@luz Thank you, I finally solved this! Ordered bunch of 74HC125D chips, there are four gates per chip. I pass through the gate only the CLK line, assuming that any MOSI traffic will be ignored by the strip when there is no CLK. So far so good, it seems that both flash memory (device 0), and LED strip are working just fine.
@Pavils-Jurjans Ok, finally, got this working! The missing data problem was solved by changing the frequency to 200KHz. Apparently, the hardware SPI gets unreliable with low frequencies. Now I wonder what is the maximum frequency, as I tried 3.2MHz and it still works (For my 300 pixel APA102 RGB LED strip, I measure about 200 updates per second).
If disconnect WS2813 from omega2 pin and connect again - then WS2813 behaves wrong.
Note that WS2813 DIN pins are quite delicate, and very easy to destroy or at least get a latch-up.
Never send a data signal to a WS2813 which is not powered with 5V properly.
if the cable is longer than a few inches, use a shielded cable for the data.
maybe use a serial resistor in the data line to dampen spikes a bit - you have quite heavy undershoots on your scope diagrams you posted earlier in this thread.
First pixel sometimes shifting. For strip consisting of 10 LEDs - in programm we must write 11 LEDs
Sounds like a damaged first LED to me.
I thought it was a problem on my side. But no. It in Omega or yours side.
I'd be surprised.
Because in the meantime, I have used the exact same circuitry for a large installation with 20 Omega2 each driving 518 WS2813, and all of them ran 100% stable severals days uninterrupted. One of these panels still is in my office and I use it to test new stuff every day, and it runs practically 24/7.
Only one caveat: if you have software installed that makes use of the other hardware PWM unit's interrupt, please make sure to use the latest p44-ledchain (OpenWrt 18.06 build here), because there was a bug in handling the PWM interrupts.
This is not the first time, topics came out and end up to be an Omega2S related subject.
(And only in recent days, the 2S can be purchased in low quantity,
but still the dev board costs quite a bit.
The alternative is for a design house commits to go that route to layout its own board with 0.05 inch pitch footprint for 2S.)
I.e., if the OP stated 2S is the target, I would have never bothered to respond. Sorry
(or until the days the 2S has a low-cost breakout board or a hobbyist solution...)