TM4C1237H6PZ: Reduce Speed of USB when connected to Laser Printer

Naman Kumar

Part Number: TM4C1237H6PZ

Hello,

I need to reduce the speed of USB data transfer to my Laser printer when connected to TM4C1237H6PZ, due to some hardware issues. Right now, it is operating in full speed mode. Please let me know if there is a way to do so(operate it in Low speed Mode). I am not able to find any API or register to set in the datasheet.

Regards,

Naman

over 6 years ago

0 Ralph Jacobi over 6 years ago

TI__Guru*** 128095 points

Hello Naman,

Our TivaWare USBLib does not support Low Speed mode. You would need to modify the library yourself to use Low Speed mode. Also you would need to account for the Low Speed mode device errata: www.ti.com/.../spmz849f.pdf

0 Naman Kumar over 6 years ago in reply to Ralph Jacobi

Intellectual 430 points

Hi Ralph,

Thanks for the reply. I will check the same.

Regards,
Naman

0 cb1_mobile over 6 years ago in reply to Naman Kumar

Guru 117850 points

Are newly arriving thread readers not, "Left to wonder" - just how has this thread been, "Resolved?"

0 Naman Kumar over 6 years ago in reply to cb1_mobile

Intellectual 430 points

This is not resolved yet. I marked it as resolved becoz the way to solve the problem was provided to me. If I get the solution, I will post it.

0 Robert Adsett over 6 years ago in reply to Naman Kumar

Guru 27665 points

One general question and I'm not sufficiently familiar with USB to know the answer. Does the USB protocol/USB printer profile not provide a mechanism for flow control? Surely it must since the transfer rates exceed what printers are capable of.

Robert

0 Ralph Jacobi over 6 years ago in reply to Robert Adsett

TI__Guru*** 128095 points

Hello Robert,

I believe the Control Transfer type of USB transfer works similar to UART flow control: www.beyondlogic.org/.../usb4.shtml

0 cb1_mobile over 6 years ago in reply to Ralph Jacobi

Guru 117850 points

Greetings Ralph, Robert, Naman,

"Works similarly" may have to include the "hedge" that, "Past UART Flow Control" could elect Hardware or Software methods. (i.e. CTS/RTS were "pure hardware") Clearly USB provides no such "similar" hardware ( auxiliary signal) flow support...

It must be then that USB (may) support something similar to past (UART Software) "X-On/X-Off." (note that I could not connect to the posted link - yet the "limitations of the USB signal inventory" renders "hardware flow control" as, "unlikely.")

Poster's need IS valid - although it is hard to imagine that, "Speed and only speed" has been "conclusively determined" as his (sole) issue. (i.e. We've not been told (or I've simply missed) whether the printer is UART (or even) Parallel Data interfaced - thus the "hardware challenge" resides w/in the conversion process - not entirely w/in "USB.") Let the record show that our firm has (still working) Laser Printers which support Parallel Transfer (HP-4L).

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TM4C1237H6PZ: Reduce Speed of USB when connected to Laser Printer