Programming Data Into Flash Memory - Fujitsu F2MC-8FX Hardware Manual

CHAPTER 28 256-KBIT FLASH MEMORY
28.6.2

Programming Data into Flash Memory

This section explains the procedure for entering the write (program) command to
program data into flash memory.
Programming Data into Flash Memory
• To start the automatic algorithm for programming data into flash memory, send the program command
in the command sequence table continuously from the CPU to flash memory.
• Upon completion of data programming to a target address in the fourth cycle, the automatic algorithm
starts automatic programming.
How to specify addresses
• Programming (writing) can be performed even in any order of addresses or across a sector boundary.
Data written by a single program command is only one byte.
Notes on programming data
• Bit data cannot be returned from "0" to "1" by programming. When bit data "1" is programmed to bit
data "0", the data polling algorithm (DQ7) or toggle operation (DQ6) is not terminated, the flash
memory element is determined to be defective, and the execution time-out flag (DQ5) detects an error to
indicate that the specified programming time has been exceeded.
When data is read in the read/reset state, the bit data remains "0". To return the bit data from "0" to "1",
erase flash memory.
• All commands are ignored during automatic programming.
• If a hardware reset occurs during programming, the data being programmed to the current address is not
guaranteed. Retry from the chip-erase command.
Flash Memory Programming Procedure
• Figure 28.6-1 gives an example of the procedure for programming data into flash memory. The
hardware sequence flags can be used to check the operating state of the automatic algorithm in flash
memory. The data polling flag (DQ7) is used for checking the completion of programming into flash
memory in this example.
• Flag check data should be read from the address where data was last written.
• Because the data polling flag (DQ7) and execution time-out flag (DQ5) are updated at the same time,
the data polling flag (DQ7) must be checked even when the execution time-out flag (DQ5) is "1".
• Similarly, the toggle bit flag (DQ6) must be checked as it stops toggling at the same time as when the
execution time-out flag (DQ5) changes to "1".
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