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afry-south / dragonfly-fcb

ÅF Dragonfly Quadrotor UAV Project
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Increase USB communication speed #40

Open stenbergd opened 9 years ago

stenbergd commented 9 years ago

The USB is configured to emulate a UART RS232 com port, currently set to communicate at 115200 baudrate. Investigate if this can be configured to higher speed since USB allows much higher data rate.

This may be needed to ensure sensor data samples etc can be transmitted with high enough sample rate.

Does the STM32 VCP Windows Driver support higher speeds? Are there alternative CDC/VCP drivers?

Windows has its own USB CDC driver for serial com: https://msdn.microsoft.com/en-us/library/windows/hardware/dn707976(v=vs.85).aspx

provides some support on developing a Windows application

USB driver buffer size 64 bytes? We can only transmit up to 64 bytes at a time?

adam-at-epsilon commented 9 years ago

it seems that using snprintf, we can only use 64 bytes at a time and longer messages get fragmented.

This is by trial-and-error, the cause could either be the STM32 or Windows USB driver.

stenbergd commented 9 years ago

https://my.st.com/public/STe2ecommunities/mcu/Lists/STM32Discovery/Flat.aspx?RootFolder=https%3a%2f%2fmy%2est%2ecom%2fpublic%2fSTe2ecommunities%2fmcu%2fLists%2fSTM32Discovery%2fUSB%20HID%20or%20%20CDC&FolderCTID=0x01200200770978C69A1141439FE559EB459D75800084C20D8867EAD444A5987D47BE638E0F&currentviews=1618

Discussion regarding USB Speed, is 1.2 MB/s possible?