I noticed there is a port next to the HDMI on my Radxa Zero 3W.
It looks similar to some ports on Raspberry Pi boards.
Thank you for your help!
This is not really a port per se. Port usually carries some signal, but as you can see on the Raspberry Pi, not all such dots are labeled.
The labeled dots are usually called test points (like the GND TEST POINTS). Those are used during manufacture to test if the function is working without plugging devices to various real ports. The specific device used for this purpose is a flying probe tester:
Those points can also serve another function even if they do not carry any electronic signal: alignment. The SMD placement machine has cameras, and can use those dots to figure out the board position, similar to the 3 corner black squares on a QR code.
On ZERO 3W, you are looking at one such point, where it is only used to assist manufacture. It does not carry any signal.
Thank you for the detailed explanation about the port/test point.
I have a follow-up question:
Is there any possibility of transmitting a signal through any other port on the Radxa that is similar to the TV pin signal on the Raspberry Pi? Could this be achieved using UART?
Thank you!
I don’t think so. I browsed the SoC datasheet and it doesn’t look like it even has an analog video output. You may have to look into an HDMI to analog converter.
Looking at the top components placement map, this point is M1. Looking for M1 in the schematic unveils, that it isn’t connected to anything. M2, M3 and M4 aren’t connected either.
Just, TP1 (left side of USB 3.0 Host Type C port) is connected to something: SARADC_VIN0.
