provides information about two of the ARM debuggers manufactured by OLIMEX LTD – ARM-USB-OCD and ARM-USB-OCD-H. ARM-USB-OCD and ARM-USB-OCD-H are very similar in features and hardware design. Because of that when one of them is mentioned in this document it is safe to assume that the. Olimex ARM-USB-OCD-H¶. High-speed 3-IN-1 fast USB ARM/ESP32 JTAG, USB-to-RS virtual port and power supply 5VDC device. Official reference can be found here. Three-in-one USB device combining ARM JTAG debugger, virtual RS port with full modem signals supported, and power supply. ARM-USB-OCD-H Features High-Speed USB JTAG dongle interface can be used with all ARM devices for programming and debugging Standard 2×pin ARM JTAG connector Supports ARM targets working from V to V DC Supports adaptive clocking RTCK .