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PaxInstruments / labwiz-board

A development board based on the STM32 series processors specifically targeting the STM32F103RxT series.
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USB Full-Speed and High-Speed #55

Closed charlespax closed 7 years ago

charlespax commented 7 years ago

The stm32f103 is a full speed USB device. LabWiz is compatible with several microcontrollers that have high speed capability. Can we use an unused GPIO pin to to configure any necessary pullup/down resistors we need?

charlespax commented 7 years ago

I believe all devices can operate in at least high-speed USB mode (1.5k pullup on DP) and also have the option of operating in low-speed USB mode. To operate in low-Speed USB mode the board would need a 1.5k pullup on DM.

I don't really see a use case for low-speed mode, so I'm reluctant to implement any implementation that uses a pin on the microcontroller. Adding a solder jumper to the back side of the board should be fine. The user would have to cut a trace and solder a jumper. Seems reasonable for a prototyping platform. It wouldn't add any cost.

charlespax commented 7 years ago

I've added the jumper. screen shot 2017-01-24 at 12 29 40

screen shot 2017-01-24 at 12 26 26