RPI4 with TIAO Smart Sprinkler - Does not work!

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RPI4 with TIAO Smart Sprinkler - Does not work!

keitho

You can get a RPI4 for a few dollars more than a RPI3, so I gave it a try with the TIAO Smart Sprinkler board.

Turns out the TIAO Smart Sprinkler does not to work with an RPI4. The RPI4 goes into a bootloop which is caused by the +5v supplied by the TIAO Smart Sprinkler going below 4.75v shortly after the RPI4 displays the video test pattern.
This should not be an issue since the TIAO Smart Sprinkler uses a LM2956S-5.0 regulator which can supply up to 3A.
I am wondering if there is a design issue like inadequate trace width or incorrect component values.
This is happening on Two TIAO Smart Sprinkler boards.
Has anyone else seen this? I have submitted a ticket but so far no response.

keitho

OK, did a little more testing with a voltmeter. Volatrges will thus be approximate since I am not using a oscilloscope (yet).

TIAO Smart Sprinkler board with no RPI4 attached: 5.04v
With RPI4 attached at initial startup: 4.89v
At point RPI4 resets (red LED on RPI4) goes out: 4.78v

So I am betting that the trace widths on the TIAO Smart Sprinkler for +5V and/or GND are undersized and the voltage drops under the higher current needed by the RPI4 are browning out the +5V power form and causing the RPI to reset.

keitho

I have fixed the issue. Adding a 24 ga. wire between C2-positive and connector PI-10 pins 16 and 18 solved the problem. Note that the pin numbering on PI=10 is even numbered pins on one side, odd numbered pins on the other. The positive pin of C2 is the pin with the square pad.

Would have been nice to have a schematic Tiao people!

Franta71

keitho
Hi,
I do not understand the solution. I'm an amateur. my Raspberry Pi 3+ has the same problem. He could send me a drawing or a photo. What is C2 on the board? And how can I connect the pins?
Thanks in advance for your response

Frantisek