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Chapter 7. Programming the Soldered Device in the Target Hardware
IAP mode is for embedding the on chip programming facility in your target application. You may include this in your application to provide a kind
of self-upgradation facility or to get latest calibration information and etc.
You need to refer the Philips Documentation to know more on this IAP
mode and such a discussion is beyond the scope of this manual.
Topview Device Programmer A has required facility to program these
microcontrollers in Parallel Mode. You may use this Parallel Programming
facility to restore the Boot ROM in the device after it is erased.
7.3. Power on Reset Code Execution:
The controllers (with ISP facility) contain a Special flash Register, Status
Byte which indicates the starting address of the program code. At the
falling edge of reset, the controller examines the Status Byte and if the
Status Byte is set to zero, power up execution starts at location 0000H,
which is the normal start address of user application code. When the
Status Byte is set to a value other than zero, the factory masked ROM
ISP Boot loader is invoked. The factory default for the Status Byte is
FFH. Once set to 00H, the Status Byte only be changed back to FFH by
a full chip erasing when using ISP.
7.4. Hardware Activate of the Boot Loader:
The microcontroller’s Boot Loader can also be executed by holding PSEN
low, EA grater than VIH (such as +5V) and ALE high (or not connected)
at the falling edge of Reset. This is same effect as having a nonzero
Status Byte. This allows an application to be built that will normally
execute the end user ’s code but can be manually forced into ISP
operation.
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Topview Programmer A
Software User Guide