It measures 2-7/8 by 4 inches -- a pretty big board. The board is marked "CH307V-R1-1v0". There was an earlier board marked "CH307V-R0-1v0". My board is black (the earlier one was green). The earlier board had what look like 4 USB on one edge and the ethernet connector all by itself on another edge.
If you want to buy one of these, I see them for sale on "Tindie" for $29.
Here is what I see on my board:
The CH549G is described as "An 8-bit enhanced USB MCU with multiple interfaces. It provides 64K program ROM and 2K+256 RAM. It supports USB host, USB device and Type-C CC and PD. It provides 16-channel Touch-key, 16-channel ADC, 3 sets of timers, 8-channel PWM, 4-channel UART and SPI, etc." Sounds like a fancy item to use as a USB to serial interface, but it is made by the same folks who make the CH307, so it makes sense that they would use it.
2022-06-18T22:35:03.097842-07:00 trona kernel: usb 1-1.2: USB disconnect, device number 4 2022-06-18T22:35:03.880840-07:00 trona kernel: usb 1-1.2: new full-speed USB device number 5 using ehci-pci 2022-06-18T22:35:03.960832-07:00 trona kernel: usb 1-1.2: New USB device found, idVendor=1a86, idProduct=8010, bcdDevice= 2.03 2022-06-18T22:35:03.961134-07:00 trona kernel: usb 1-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 2022-06-18T22:35:03.961372-07:00 trona kernel: usb 1-1.2: Product: WCH-Link 2022-06-18T22:35:03.961685-07:00 trona kernel: usb 1-1.2: Manufacturer: wch.cn 2022-06-18T22:35:03.962019-07:00 trona kernel: usb 1-1.2: SerialNumber: 0001A0000001 2022-06-18T22:35:03.962820-07:00 trona kernel: cdc_acm 1-1.2:1.1: ttyACM0: USB ACM deviceInterestingly, with the switch "off", the upper section with the CH549 still runs and handles USB enumeration (but it repeats the exercise when you turn the switch on). With the power switch on, a second power LED on the main portion of the board comes on and at 115200 baud, I see "111\n" being sent about every second. When I press "reset", I see "SystemClk:72000000".
Tom's Computer Info / tom@mmto.org