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Chapter 14 QzROM Programming
QzROM is a new type of programmable flash memory, found in some 4 and 8 bit MCUs. It is based most
closely around the Protocol D style device but has several important differences:
• One time programming - each byte of QzROM can only be written once.
• QzROM cannot be erased - there is no erase command.
• Security Protection - QzROM has security protection. After protection, attempts to start the target MCU
for connection can result in an error status, i.e. further reads from (or writes to) the device are not
possible.
Blank check - QzROM has a Blank check command whereas other Protocol D devices don’t. If Device
Protection is set to “Automatic” or “Interactive” FDT will use this to check the device write state before
programming.
FDT is aware of QzROM based on the device that is configured for the project.
14.1 Reserved Areas
QzROM introduces the concept of ‘reserved areas’ into FDT, for example the M37545G4 has an 8-byte
reserved area within the ROM. A reserved area is a defined area of Flash that FDT will not read, write or
blank check. Within the Hex Editor these reserved areas are shown as a series of ‘**’ characters.
Figure 14-1 Hex Editor view of Reserved Area
Any attempt to type or copy data, etc. into these areas will be ignored, as will attempts to copy data out.
Files saved from this view will have no data for these areas (internally FDT treats this data as 0xFF despite
what may be read in).