The first part of the serial number should be a date code. Anything newer than a specific date should be rev C3, but I need to research the exact date codes. The easy way to recognize them is by looking at the microSD card cage that went end-of-life requiring us to update the design:
Note how the newer one’s microSD card cage has gold legs sticking outside the package, whereas they are inside the outline of the package on the older versions.
Some additional information.
The board revision is printed on the bottom side near the barrel jack:
PCB revision C is only used on rev C3 or newer boards. Older rev C, C1, C2 boards used the rev B6 PCB with only BOM updates.
The serial numbers include date codes in them. Seeed was the first to manufacture Rev C3 boards and started doing so in June 2021.
Note: the picture is from the Industrial version (red), but the same PCB is used on the normal version, just is black, instead of red.
A more important question is how U-Boot can recognize rev C3 boards, so that a complete fix for the ethernet phy bug can be implemented using the new phy reset gpio.
On the bright side, that gpio is not used on the older board, it would be safe to toggle…
Yes, but that means
while( phy is fucked )
is an infinite loop on pre-C3 boards.
A single reset should make sure the PHY is good., no?
As far as I know it’s the same dice-roll on each PHY reset, whether it’s the initial one at power-on or subsequent manual resets.