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usb cdc communication with high bit rate

abeba.1
Associate II

hii every one 

 

i implanted usb_cdc commination using  usb port , and my question is how do i transmit data or receive with high bitrates lets say with 4 5 mbits , cause when i implanted the cdc-usb  its just act like a serial port , and when i open the pc port there are standard bit rates like 115200 or 9600 etc , and i i am intersted to tarnsmite or recieve with higer bit rates how can i do that ? i be glad for help 

2 REPLIES 2
jiangfan
ST Employee

some points on this topic:

1) MCU STM32 side. STM32 needs to have high speed USB port so as to support high data rate like 4M~5Mbits/s. If STM32 only has full speed USB port, it is difficult to support 4M~5Mbits/s data rate as 12Mbits/s is theoretically max for full speed USB.

2) PC software should support high data rate like 4M~5Mbits/s. Not all PC software supports such high data rate. If remember correctly teraterm only supports up to 921.6k baud rate.

3) proper buffering needed for your usb_cdc implementation.

NOTE: STLINK V3 can support 1M baud, 2M baud seems supported if I remember correctly.

gbm
Lead III

If your CDC ACM data traffic is only between the PC and STM32, with no real UART pasthhrough, the serial port speed setting in terminal program has nothing to do with the USB data rate. Usually it's easy to achieve close to 64 kB/s, regardless of the speed set in the terminal.

My STM32 stuff on github - compact USB device stack and more: https://github.com/gbm-ii/gbmUSBdevice