TM4C1236H6PM: BULK USB communication with .Net Application

Sumit Mourya

Part Number: TM4C1236H6PM

Hello All,

Iam want to establish USB Communication with PC Host Application to be built in VB.net

The TM4C123 MCU will act as device and data will be communicated through Bulk Transfer type.

I need to transfer approx 19000 Bytes / Second from device to host. I've been following the USB_DEV_BULK EXAMPLE in Tivaware . The USB_BULK_EXAMPLE application is written in Windows C and the header files (lmusbdll.h)have been developed from the lmusbdll.dll according to the application.

However I want to use the DLL in VB.NET application . Iam taking reference of USB_BULK_EXAMPLE but functions of lmusbdll.h cannot be used in VB.net. Is there any way to access the functions inside the DLL file or any example made in VB.net or C# ? I need suggestions how to go about forward with my project.

over 5 years ago

0 Bob Crosby over 5 years ago

TI__Guru 72500 points

I am sorry, but as you can see from the file lmusbdll.cpp it is simply a thin wrapper to WinUSB from Microsoft. I cannot help you with the PC side of your application.

0 Sumit Mourya over 5 years ago in reply to Bob Crosby

Expert 1790 points

Is it possible to achieve data transfer speed of 19000bytes/second through UART?

0 Bob Crosby over 5 years ago in reply to Sumit Mourya

TI__Guru 72500 points

For 19K bytes/second you need a baud rate of at least 190K bps (bits per second). The TM4C1236H6PM UART is capable of up to 5M bps in normal mode and 10M bps in high speed mode. The physical connection, including transceivers and cable length, may limit your maximum baud rate.

0 Sumit Mourya over 5 years ago in reply to Bob Crosby

Expert 1790 points

One more thing. Most of the SERIAL-USB Converter chips like FTDI(FT232) might not be able to support baud rates upto 5Mbps or 10Mbps. Maximum they achieve is 3Mbps. How to utilize the 5Mbps UART Speed of the MCU? I have to use a serial to USB converter to connect to a PC.

0 Bob Crosby over 5 years ago in reply to Sumit Mourya

TI__Guru 72500 points

The baud rate for the TM4C1236H6PM device is up to 5M bps. You can run it slower. You can pick a standard baud rate faster than 190K bps that is supported by the FTDI chip. The TM4C has integer and fractional divisors to allow it to match most baud rates. (I think the FTDI chips do too.)

Here is some information from FTDI:
www.ftdichip.com/.../AN232B-05_BaudRates.pdf

0 Bob Crosby over 5 years ago in reply to Bob Crosby

TI__Guru 72500 points

To be more specific, you could use a 1M bps rate. The FTDI device uses 48MHz/16 for a 3MHz maximum rate and the TM4C use 80MHz/16 for a 5MHz maximum rate. Using integer divide by 3 on the FTDI chip and an integer divide by 5 on the TM4C matches them both up nicely at 1M bps, which is 5 times the minimum rate you require. The paper from FTDI cited above will guide you on aliasing that baud rate a standard Windows baud rate if that is required.

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TM4C1236H6PM: BULK USB communication with .Net Application