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STM32L052 USB communication problems

Question asked by kamlah.siegfried on Jan 24, 2017
Latest reply on Jan 26, 2017 by Nor Sch



I'm running in some communication problems with USB at the STM32L052 on Linux. If the device is connected via /dev/ttyACM0 and transmitting data to the host, I see an echo on the receive buffer inside the STM. If the host request another data packet than, the STM32 doesn't regconize the request.



STM is transmitting "This is a test". The STM receives several packets interrupts as:

1) "This"

2) " is "

3) "a tes"

Lenght is except for the first packet always 4.


If the STM is connected as /dev/ttyACM1, everything is working fine. No echo is received.


Is there anything known?


Project is build with:

+ CubeMX 4.19.0

+ HAL-Lib STM32Cube_FW_L0_V1.7.0

+ Atollic TrueStudio


Kind regards

Siegfried Kamlah