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デバイス : MachXO2、MachXO3LF

There are two possible methods, shown below. There are two sectors of internal flash memory (CFM: Configuration Flash Memory, UFM: User Flash Memory).

The CFM sector holds configuration information and the UFM sector is an area for arbitrary user information. Both of the following can be programmed by the programmer as part of the Jedec file and can be read/write accessed by an external controller or internal logic after configuration.

1. Save to UFM
The UFM can perform Program/Erase processing independently from the CFM, and access each page with 256 bits as one page (the number of UFM pages depends on the device size). Erasing or rewriting the CFM is unaffected, but if you want to erase or change even one page that has already been programmed, you must erase the entire UFM. Therefore, if there is page information to be retained, it will be temporarily saved somewhere before erasing and then written back.

2. Save as "USERCODE" in CFM
Limited to 32bit, but can store any value. However, since it is included in the CFM, it will be erased when the CFM is erased for rewriting in a field update, etc., so countermeasures such as rewriting are required.