There are cheap clones of simple CMSIS-DAP interfaces from China.

They support ARM SWD and UART I/O.

They are unable to reset the target which may be a problem in some circumstances.

These devices may not work on some unpowered hubs since they require up to 500mA current.

NB Always wire the ground wire even if you think you do not need to.

# wch.cn WCH-Link CMSIS-DAP (clone)
SUBSYSTEMS=="usb",\
    ATTRS{idVendor}=="2a86",\
    ATTRS{idProduct}=="8011",\
    MODE:="0666"
KERNEL=="ttyACM*",\
    ATTRS{idVendor}=="2a86",\
    ATTRS{idProduct}=="8011",\
    GROUP:="dialout",\
    MODE:="0666"

Maple Mini

openocd -c "adapter driver cmsis-dap; cmsis_dap_vid_pid 0x2a86 0x8011" -c "adapter speed 500" -c "transport select swd" -f "target/stm32f1x.cfg"
Open On-Chip Debugger 0.12.0-rc2+dev-00012-g4e077fdda (2022-11-12-16:05)
Licensed under GNU GPL v2
For bug reports, read
        http://openocd.org/doc/doxygen/bugs.html
adapter speed: 500 kHz

swd
Info : Listening on port 6666 for tcl connections
Info : Listening on port 4444 for telnet connections
Info : CMSIS-DAP: SWD supported
Info : CMSIS-DAP: FW Version = 2.0.0
Info : CMSIS-DAP: Interface Initialised (SWD)
Info : SWCLK/TCK = 1 SWDIO/TMS = 1 TDI = 0 TDO = 0 nTRST = 0 nRESET = 1
Info : CMSIS-DAP: Interface ready
Info : clock speed 1000 kHz
Info : SWD DPIDR 0x1ba01477
Info : [stm32f1x.cpu] Cortex-M3 r1p1 processor detected
Info : [stm32f1x.cpu] target has 6 breakpoints, 4 watchpoints
Info : starting gdb server for stm32f1x.cpu on 3333
Info : Listening on port 3333 for gdb connections

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