ASUS Tinker Board S

ASUS publishes the full schematic for this board. A single-page PDF sits on the same download server as the manual, and opening it shows the real thing: net names like VCC_SYS, VDD_CPU, and VDD_GPU, the GPIO rails, the Rockchip RK3288 reference design laid out the way the engineers drew it. Mainstream vendors almost never do this. The whole reason this lab exists is that hardware documentation keeps quietly going offline, so a big motherboard maker choosing to post the schematic for a mass-market board is worth writing down before it changes its mind.

The board itself is the eMMC version of ASUS’s Raspberry Pi-shaped single-board computer. ASUS announced the Tinker Board S at CES 2018 at $79.99, and the “S” is the entire distinction: it is the plain Tinker Board with 16 GB of eMMC soldered on. In the SD-card era that was a real answer to a real problem, since a card that corrupts itself under a power cut takes the whole system with it, and a soldered eMMC does not fall out or wear the same way. Under the eMMC it is the same machine as the original Tinker Board of February 2017 (a date I am taking from Wikipedia for context, not as a verified figure): a quad-core Cortex-A17 RK3288, 2 GB of LPDDR3, gigabit Ethernet on its own controller rather than hung off USB, and a 40-pin header in the Raspberry Pi’s shape and pinout.

There are two things wearing the “Tinker Board S” name, and they are not the same board. The original 2018 unit uses a discrete AW-NB177NF Wi-Fi module. A later R2.0 revision, which CNX Software covered in April 2023, swaps that for a Realtek combo chip and offers more RAM and eMMC. This page documents the original. Later still ASUS shipped the Tinker Board 2 and 3, which are different hardware again and out of scope here. Which of the two S boards is actually on my bench is the first thing I need to settle, and it is settled by eye — the original’s separate Wi-Fi daughter module looks nothing like the R2.0’s single combo chip near the antenna connector.

I bought this one on Amazon. What I have not yet recorded is which revision it is, what I have run on it, or what job it holds — if any. I have listed it as shelved rather than in use, but that is a placeholder, not a finding: I have no note giving it work and will not invent one. As a build target it is another 32-bit ARMv7 machine, which is the kind of thing the release engineering platform needs on the bench and not in a spreadsheet, but whether this board has ever served that platform is one of the open questions, not a claim.

The full specifications, including the two places ASUS’s own documents disagree with each other, are on the specifications page. Sources: the ASUS Tinker Board S user manual (E13446, December 2017), the ASUS schematic PDF (opened and read directly), the current ASUS product page, and CNX Software’s and Engadget’s contemporaneous launch coverage from January 2018.