Segger J-Link - Page 229

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5.12.1.25InvalidateCache
This command is used to invalidate cache.
Syntax
InvalidateCache
5.12.1.26InvalidateFW
This command is used to invalidate the current firmware of the J-Link / J-Trace. Inval-
idating the firmware will force a firmware update. Can be used for downdating. For more
information please refer to J-Link / J-Trace firmware on page 446.
Syntax
InvalidateFW
5.12.1.27map exclude
This command excludes a specified memory region from all memory accesses. All
subsequent memory accesses to this memory region are ignored.
Memory mapping
Some devices do not allow access of the entire 4GB memory area. Ideally, the entire
memory can be accessed; if a memory access fails, the CPU reports this by switching
to abort mode. The CPU memory interface allows halting the CPU via a WAIT signal.
On some devices, the WAIT signal stays active when accessing certain unused mem-
ory areas. This halts the CPU indefinitely (until RESET) and will therefore end the
debug session. This is exactly what happens when accessing critical memory areas.
Critical memory areas should not be present in a device; they are typically a hard-
ware design problem. Nevertheless, critical memory areas exist on some devices.
To avoid stalling the debug session, a critical memory area can be excluded from
access: J-Link will not try to read or write to critical memory areas and instead
ignore the access silently. Some debuggers (such as IAR C-SPY) can try to access
memory in such areas by dereferencing non-initialized pointers even if the debugged
program (the debuggee) is working perfectly. In situations like this, defining critical
memory areas is a good solution.
Syntax
map exclude <SAddr>-<EAddr>
Example
This is an example for the map exclude command in combination with an NXP
LPC2148 MCU.
Memory map
0x00000000-0x0007FFFF On-chip flash memory
0x00080000-0x3FFFFFFF Reserved
0x40000000-0x40007FFF On-chip SRAM
0x40008000-0x7FCFFFFF Reserved
0x7FD00000-0x7FD01FFF On-chip USB DMA RAM
0x7FD02000-0x7FD02000 Reserved
0x7FFFD000-0x7FFFFFFF Boot block (remapped from on-chip flash memory)
0x80000000-0xDFFFFFFF Reserved
0xE0000000-0xEFFFFFFF VPB peripherals
0xF0000000-0xFFFFFFFF AHB peripherals