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Regular Visitor
bbtaylr
Posts: 5
Registered: ‎01-07-2012
Accepted Solution

USB UART

I was trying to test a bootloader (failed attempt) by attempting the 6th tutorial and I blew away the factory image in the SPI flash.  Prior to this, I would see the USB UART appear as ttyUSB0 as one of the linux devices when doing a "ls /dev*".  Since the failed bootloader attempt, I don't see ttyUSB anything.  This makes it difficult to re-try the bootloader or any application with console output in the application.

 

I tried downloading the Lab6 and running the canned project with no change.

 

Any suggestions as to how to get console output again?  Is the project for the factory installed image available?

 

 

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Avnet Employee (Star Contributor)
JBethurem
Posts: 181
Registered: ‎02-18-2010

Re: USB UART

 

Hmmm.  The USB-UART chip is not programmed by the FPGA, its preprogrammed, thus, no matter what you do
to the FPGA, it should work fine.    Though if the FPGA is unprogrammed, its I/O will be tri-stated or pulled low.
Thus I don't know how that will affect the USB-UART.   

 

You can reprogram the factory test image by going the LX9 MicroBoard's Support Files and Downloads page.
Near the bottom is:

 

Jayson

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Regular Visitor
bbtaylr
Posts: 5
Registered: ‎01-07-2012

Re: USB UART

Thanks loads Jayson,

 

I got the image flashed and now have ttyUSB0 back again.

 

Based on your comments, I will have to look into this some more to understand how the USB device on the board became disabled.

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Avnet Employee (Star Contributor)
professor
Posts: 101
Registered: ‎06-09-2009

Re: USB UART

Hi Bob,

 

I went through this tutorial just for fun and I also got hung up on my Ubuntu 10.04LTS system.  However, I went back through the instructions more closely and noticed in the tutorial document, Experiment 4, Step 3 the instructions say to configure the terminal for 9600 baud.  I double checked the mb_system/mb_system.mhs file and sure enough, the axi_uartlite core is configured for 9600 baud.

 

BEGIN axi_uartlite
 PARAMETER INSTANCE = USB_Uart
 PARAMETER HW_VER = 1.02.a
 PARAMETER C_BAUDRATE = 9600
 PARAMETER C_DATA_BITS = 8
 PARAMETER C_USE_PARITY = 0
 PARAMETER C_ODD_PARITY = 1
 PARAMETER C_BASEADDR = 0x40600000
 PARAMETER C_HIGHADDR = 0x4060ffff
 BUS_INTERFACE S_AXI = axi4lite_0
 PORT S_AXI_ACLK = clk_100_0000MHzPLL0
 PORT TX = USB_Uart_sout
 PORT RX = USB_Uart_sin
END

 

This is one definite difference from the factory test project as I know for sure the axi_uartlite core is configured for 115200 baud.  I went back to minicom and reconfigured ttyUSB0 settings for 9600, reconnected, and I was able to view the terminal output for the bootloader (see attached screenshot).

 

Not sure if this is the exact problem that you are running into, but it was something I got stuck on for a bit.

 

Regards,

 

-Kevin

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Regular Visitor
bbtaylr
Posts: 5
Registered: ‎01-07-2012

Re: USB UART

Thanks Kevin,

 

I'll see if that might have been the case for my project too.

 

Bob

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Regular Visitor
bbtaylr
Posts: 5
Registered: ‎01-07-2012

Re: USB UART

Kevin,

 

You were right... my USB UART was set to 9600 baud...  you probably saved me a ton of grief.

 

Bob

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