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11 years, 2 months ago.
Problem in reading USB Mass Storage Device using mbed LPC 1768
Hello Sir, Please help me out in reading USB Mass storage device using mbed LPC1768. I have been using Igor skochinsky's code to read USB Mass storage Device using mbed LPC 1768 and it was working fine earlier(a month before). The code was able to display the USB enumeration data, list of files in USB mass storage device,read and write acknowledgement data. But now I am using the same code to read the USB,but I am unable to get the list of files in USB. I am just getting the following output in hyperterminal
USB Mass Storage Demo Program for mbed LPC1768
Reading USB memory
In Host_Init Initialising Host Stack Host Initialised
Connect a Mass Storage Device
I tried with the couple of other mass storage devices too,.its not working,. Please help me out
Prashanth Shetty prashanthshetty149@yahoo.com
1 Answer
11 years, 2 months ago.
You're not getting the interrupt to tell the code about an inserted USB stick.
Have you added the pull-down resistors to the USB signal lines (D+ an D-)?
You need 15K resistors, 5% or better.
The Stick pulls one line HIGH to announce its arrival in the socket - and without pulldown resistors, the transition will not be reliably made.
Hello Rod Coleman,as per your suggestion i added the pull down resistors of 15k and 5% tolerance to USB signal lines(D+ and D-).Still the problem is persisting.And before(before a month) I was working with the same code earlier without pull down resistors connected.It was working fine.But now its not working!!!..
posted by 14 Feb 2013