Keil uVision Debug Mode exiting whilst executing program that accesses PSRAM
The problem occurred whilst using the AT91SAM3U-EK & Keil ULINK Pro JTAG probe @48MHz.

A simple program (main loop incrementing a loop count and outputting the loop
count to the serial port using 'printf()') is using internal ROM, internal RAM
for stack, and PSRAM for the heap. The Static Memory Controller is setup using a
debug .ini script and the program loaded using the debug LOAD command. (Script
provided by ATMEL to setup the Static Memory Controller to run @48MHz). The uVision
enters debug mode and loads the program OK. The program runs OK but after a random
amount of time the debug mode is exited, however the program continues to execute
normally. When the heap is located in internal RAM the debugger behaves correctly
(overnight run).

Tools & Environment
-------------------

uVision V4.20.03.0
ToolChain: MDK-ARM Professional Version 4.20
C Compiler: ARMcc.exe V4.1.0.644
Linker: ARMLink.exe V4.1.0.644

CPU DLL SARMCM3.DLL V4.20
Dialog DLL: DARMSAM3.DLL V1.09
Target DLL: BIN\ULP2CM3.DLL V2.50
Dialog DLL TARMSAM3.DLL V1.08

ULINK Pro Settings
------------------

Device Family Cortex-M
Firmware Version V1.50
SWJ-checked PORT-JTAG
Max XClock 1MHz
Debug Connect -Normal
Reset -Autodetect
Reset after Connect -Checked
Cache Options
Cache Code -Checked
Cache Memory -Checked

Target
------
AT91SAM3U4E Device
ATSAM3U-EK Board
MCLK 48MHz
IROM1 0x80000 0x20000
IRAM1 0x20000000 0x8000
PSRAM 0x60000000 0x100000