UPD78F9234MC-5A4-A Datasheet, PDF (298/419 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

CHAPTER 19 FLASH MEMORY
19.8.5 Example of shifting self programming mode to normal mode
The operating mode must be returned from self programming mode to normal mode after performing self
programming.
An example of shifting to normal mode is explained below.
<1> Clear FLCMD (FLCMD = 00H).
<2> Clear the flash status register (PFS).
<3> Set normal mode using a specific sequence.
• Write the specific value (A5H) to PFCMD.
• Write 00H to FLPMC (writing in this step is invalid)
• Write 0FFH (inverted value of 00H) to FLPMC (writing in this step is invalid)
• Write 00H to FLPMC (writing in this step is valid)
<4> Check the execution result of the specific sequence using bit 0 (FPRERR) of PFS^Note.
Abnormal → <2>, normal → <5>
<5> Enable interrupt servicing (by executing the EI instruction and changing MK0 and MK1) to restore the original
state.
<6> Mode shift is completed
Note Restore the CPU clock to its setting before self programming, after normal execution of the specific
sequence.
Caution Be sure to perform the series of operations described above using the user program at an
address where data is not erased or written.
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User’s Manual U17446EJ5V0UD