WeAct's $10 USB 3.0 Logic Analyzer Doubles as a Three-Port Serial Adapter and Arm Debugger

Most benches own three small tools that all live in the same drawer: something to watch signals, something to talk serial, and something to flash and debug a chip. WeAct Studio’s Logic Analyzer V2 is all three, one at a time, in a 42.5 by 26.5 by 13 mm case. Its README sums it up in six words: “Three apps on one board, switched with the key.”

The trick is flash. Each app gets its own 304 KB slot, with the first 24 KB of each slot reserved for the in-application programming code that handles updates. Slot 0 is the logic analyzer, slot 1 is the USB-to-serial and debugger firmware, and slot 2 is for custom firmware. CNX Software’s Jean-Luc Aufranc reports the board sells on AliExpress for about $10 plus shipping and taxes.

You switch slots two ways. The README says to “hold 2 s until the LED turns white, then release.” The other is software: set a serial port’s baud rate to 2049, 2050 or 2051 to pick slot 0, 1 or 2. Dialing a baud rate to change what a device is has to be the nerdiest mode switch since the Konami code. (Hold the key at power-on instead and you land in the update mode.)

As a logic analyzer it takes 16 channels, configurable as 2, 4, 8 or 16. Over USB 3.0 the README gives a sample rate of 4 to 200 MHz; over USB 2.0 it drops to 4 to 20 MHz with all 16 channels, or 4 to 40 MHz with eight. It ships with 132 protocol decoders, including UART, I²C, SPI and CAN. The brain is a WCH CH32H417, which CNX describes as a RISC-V chip with a core up to 400 MHz plus a second one at 144 MHz. In the CNX spec list, a capture runs for roughly 45 seconds at 200 MHz on 16 channels, limited by memory on the PC, and inputs take 1.0 to 3.3 volts.

In serial mode it becomes “3× CDC up to 9 Mbps + CMSIS-DAP v2 SWD probe,” in the README’s words: three serial ports and a debugger. The debug probe is “driver-free over WinUSB,” with SWD on three pins (D6 for clock, D8 for data, D7 for reset), and WeAct has a CMSIS-DAP flasher for Arm Cortex-M targets.

Here is how it lines up against DreamSourceLab’s DSLogic U3Pro16 and the Saleae Logic 8, figures from each maker’s own page:

	WeAct Logic Analyzer V2	DSLogic U3Pro16	Saleae Logic 8
Price	About $10 plus shipping (CNX)	$299 (store price, marked down from $399)	Not shown on its product page
Channels	16	Up to 16	8
USB	3.0	3.0	Not stated on the page
Fastest sample rate	200 MHz, 16 channels	500 MHz at 16 channels in buffer mode; 125 MHz in stream mode	“up to 100 MS/s”
Desktop software	Windows, Linux	Windows, macOS, Linux	Windows, macOS, Linux
Also a serial adapter and Arm probe	Yes	No	No

The cheap end of the market, on the other hand, is a sea of Cypress FX2 boards. Sigrok’s fx2lafw page lists roughly twenty eight-probe devices that all run the same firmware off a 24MHz crystal, including WeAct’s own earlier LogicAnalyzerV1. That is the neighborhood this board comes from.

The software side has its own fine print. The desktop app, U3LogicAnalyzer, is a sigrok-based program for Windows and Linux, and no Mac build is listed. CNX also suspects the board wasn’t added upstream to sigrok because that project looks dormant, which it presents as speculation.

Speed needs a footnote too. 200 MHz is how often the board samples, not how fast a signal it can read cleanly, and the README gives no bandwidth figure. Check the edges you care about before you trust them.

Source code is included for exactly one slot, the one you write yourself.