It is possible.
If the flash memory is compatible with the JEDEC or CUI commands and can be programmed by a single power supply, programs and data can be downloaded by wiring the user system so that the microcontroller can write data to external flash memory. However, this method is limited to debugging and cannot be used for programming at mass production.
Outline of procedure for downloading programs and data to the flash memory connected to the external bus
- Design a user system allowing external flash memory to be programmed.
- Input the information on the flash memory in use and the information for connection to the user system (address, bus width, etc.) to the external flash definition editor (EFE).
Note: For information on the external flash definition editor, refer to the datasheet from here.
- Create a batch file (enables the external bus, enables the chip select pin, sets the number of wait states, etc.) that sets up the bus controller so that the microcontroller can access external flash memory and register it to EFE.
If the error message of "Maker ID or device ID for the external flash ROM is not corresponding. " is displayed at download, recheck the settings because it is highly possible that the created batch file is the cause.
We also recommend adding the statement for selecting the high-speed CPU clock to the batch file because downloading may take an excessively long time or end abnormally if the low-speed CPU clock (low-speed on-chip oscillator) is selected.
- Create a USD file with EFE.
- Register the USD file generated to the e² studio,High-performance Embedded Workshop or CS+.
It is possible to program by performing the same processing as the batch file using the function of a debugger for automatic memory manipulation before downloading, without using the batch file created in step 3.
Since the result of the batch file processing cannot be checked on the memory panel of a debugger, this is the only way to check whether the register has been modified.
- Using a normal download procedure, download a program including the data to be written to external flash memory.
Note that functions for downloading programs and data, performing single-step, and using an on-chip break in external flash memory can be used but functions that result in rewriting the contents of flash memory (rewriting flash memory in the Memory window or using a software break) cannot be used.
|CS+ (formerly CubeSuite+)|
|High-performance Embedded Workshop|
|External Flash Definition Editor|