AHB SRAM and USB cannot be used same time

lpcware — Wed, 15 Jun 2016 19:22:24 GMT

Content originally posted in LPCWare by jpplus on Wed Dec 10 17:24:59 MST 2014
Dear all,
I observed an issue that in LPC4337, the AHB SRAM(0x20000000) and USB cannot access same time.
I have small piece of code to verify that. When comment out memcpy to wrting to AHB SRAM, then USB can run. After adding back that line, USB stop. This line does nothing bad, just write to 0x20000000.

   while(1) {
                void * dest=(void *)0x20000000; //an example of accessing AHB SRAM
memcpy(dest, (void *)buffer, sizeof(buffer)); //comment out this line, then USB works, if adding this line, USB does not print anything. This line will  not do anything harm to system.

 vcom_write("Hello world!!\n\r");


}

I guess it should conflict of the AHB, but in data sheet, there are few words about that. how to solve this kind of issue?
thanks a lot

Re: AHB SRAM and USB cannot be used same time

lpcware — Wed, 15 Jun 2016 19:22:25 GMT

Content originally posted in LPCWare by mc on Mon Jan 26 13:07:01 MST 2015
Hi jpplus,
Which USB stack are you using? Could you please post your full example?
Looks like it is a S/W issue.

topic AHB SRAM and USB cannot be used same time in LPC Microcontrollers

AHB SRAM and USB cannot be used same time

Re: AHB SRAM and USB cannot be used same time