USB and AHB for LPC4337

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 Tue Dec 09 21:46:54 MST 2014
I get a strange issue that USB cannot work when any code accessing of AHB.
I get below code, the debug_printf function is basically print out msg via USB.
when I comment out the code of memcpy to avoid access AHB SRAM, then USB can print out hello world.
if I add that memcpy, then USB cannot print out.
I guess there is some setting of AHB priority, but basically I need the higher priority of the memcpy
The hardware is 4337.

                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.
count = debug_printf("Hello world!!\n\r");