Freescale Semiconductor Microcontrollers - Manual (Page 92)

Debugger Components
General Debugger Components
92 Microcontrollers Debugger Manual
Banked/Window Paged Memory: Physical/Local
vs. Logical display
This section applies only to devices having on-chip program pages or data pages. For
Legacy reasons, the debugger provides two ways to display the banked/window paged
memory, such as the PPAGE window $8000-$BFFF range with HCS08 devices with on-
chip MMU, or EEPROM windows bit selectable:
• The default display is called the physical display in the Debugging Memory Map
(DMM) interface. It is sometimes called the local display in device specifications
and matches exactly what the CPU “sees” for silicon memory. This means that what
is displayed in the Memory window at a specific suspended time (debugger halted)
matches the current setup of Page registers (like PPAGE) or selection bit like
EPGSEL for EEPROM, etc. Changing the page registers or selection bit and then
refreshing the Memory window immediately shows changes in the window range.
• The logical display gives a constant Memory view at a specific address. For example,
if we define, in a window address range, the concatenation of PPAGE<<16 added
with the physical/local address, we obtain a 24-bit address that does not represent
anything for the CPU, but that is directly readable by the user in the Memory
window.
By default, for 8/16-bit devices, the debugger displays memory addresses above address
0xFFFF as logical. These addresses do not represent actual addresses anymore, but are
still required by the debugger to synchronize the program flow display and data accesses
within all windows.
The debugger defines page range accessibility in the DMM interface. Also, for 8/16-bit
devices, in the physical/local $0000-$FFFF, the window ranges can be also defined as
logical in the DMM interface, to make them constant at display. For example, the range
$8000-$BFFF program window can be changed from physical to paged (also EEPROM
paged for paged EEPROM) in the DMM graphical user interface, and the debugger no
longer displays what the CPU “sees”, but always displays PPAGE $00 when looking at
addresses in the $008000-$00BFFF range.
The debugger provides by default a mixed display, that can be quickly changed when
editing the module setup in the DMM interface. Refer to
Debugging Memory Map for
further details.
Memory Operations
• Double-click a memory position to edit it. If the memory is not initialized, this
operation is not possible.
• Drag the mouse in the memory dump to select a memory range.