TMP86FS49AIUG datasheet(246/296 Pages) TOSHIBA

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19. Flash Memory

19.4 Access to the Flash Memory Area

TMP86FS49AIUG

19.4.2 Flash Memory Control in the MCU mode

In the MCU mode, write operations are performed by executing the control program in the RAM area.

Before execution of the control program, copy the control program into the RAM area or obtain it from the

external using the communication pin. The procedures to execute the control program in the RAM area in the

MCU mode are described below.

19.4.2.1 How to write to the flash memory by executing a user write control program in the

RAM area (in the MCU mode)

(Steps 1 and 2 are controlled by the program in the flash memory, and steps 3 through 11 are controlled

by the control program in the RAM area.)

1. Transfer the write control program to the RAM area.

2. Jump to the RAM area.

3. Disable (DI) the interrupt master enable flag (IMF

←"0").

4. Disable the watchdog timer, if it is used.

5. Set FLSCR<FLSMD> to "0011B" (to enable command sequence execution).

6. Execute the erase command sequence.

7. Read the same flash memory address twice.

(Repeat step 7 until the same data is read by two consecutive read operations.)

8. Execute the write command sequence. (It is not required to specify the bank to be written.)

9. Read the same flash memory address twice.

(Repeat step 9 until the same data is read by two consecutive read operations.)

10. Set FLSCR<FLSMD> to "1100B" (to disable command sequence execution).

11. Jump to the flash memory area.

Note 1: Before writing to the flash memory in the RAM area, disable interrupts by setting the interrupt master

enable flag (IMF) to "0". Usually disable interrupts by executing the DI instruction at the head of the

write control program in the RAM area.

Note 2: When writing to the flash memory, do not intentionally use non-maskable interrupts (the watchdog

timer must be disabled if it is used). If a non-maskable interrupt occurs while the flash memory is

being written, unexpected data is read from the flash memory (interrupt vector), resulting in malfunc-

tion of the microcontroller.

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