AHB SRAM and USB cannot be used same time

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
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