Motorola USB08 Betriebsanleitung PDF herunterladen (Seite 16)

4 MEMORY MANAGEMENT

4.1 Writing to RAM

The monitor ROM routines on the MCU are able to write directly to RAM, including the I/O registers.

4.2 Writing to FLASH

Writing to (i.e. programming) FLASH memory is carried out transparently by Xplor8, subject to

certain general conditions, as follows:

• Flash memory has been successfully unlocked

• The range to be programmed is not protected by a value in the FLBPR register - see the

HC908 data sheet.

• The appropriate utility files are available

If the above conditions are met, Xplor8 loads the necessary utility file to the RAM are of the MCU

and sends the data. Where the new data overlaps already-programmed locations, Xplor8 automatically

manages the reading-in and rewriting of memory which is not receiving new data, but which otherwise

has to be erased to allow new data to be written.

4.3 Managing the FLBPR Register

On most chips in the HC908 series, a FLBPR (Flash Block Protect) register provides some protection

against accidental erasure or change of Flash contents. On some flavors of the HC908 this register is

implemented as a Flash byte, while on others it is a RAM location that reverts to $00 (all locations

protected) on reset. It is the user's responsibility to write the FLBPR register to an appropriate value

before attempting a command to modify Flash memory. As an example, the following macro will un-

protect Flash, on a chip where FLBPR is a RAM location, erase all the Flash locations, re-protect

memory and verify that it is indeed fully erased:

DEFM EraseAll

BEGIN

R FLBPR=FF

ME FFFF

R FLBPR=00

END

4.4 Memory Map Display

This window displays the memory map for the currently selected MCU. It reflects the data supplied

in Settings>Memory.

The map may be sorted with the 'sort' button either in ascending or descending order. This window

is launched from the View menu, or by the keyboard shortcut Ctrl+M.

1 2 ... 11 12 13 14 15 16 17 18 19 20 21 ... 99 100

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Motorola USB08 Betriebsanleitung Seite 16