tmp88f846ug TOSHIBA Semiconductor CORPORATION, tmp88f846ug Datasheet - Page 197

• Manufacturer Part Number: tmp88f846ug
• Description: 8 Bit Microcontroller
• Manufacturer: TOSHIBA Semiconductor CORPORATION

18.4.2 Flash Memory Control in the MCU mode
18.4.2.1 How to write to the flash memory by executing a user write control program in the
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.
In the MCU mode, write operations are performed by executing the control program in the RAM area.
RAM area (in the MCU mode)
by the control program in the RAM area.)
(Steps 1 and 2 are controlled by the program in the flash memory, and steps 3 through 11 are controlled
Note 1: Before writing to the flash memory in the RAM area, disable interrupts by setting the interrupt master
Note 2: When writing to the flash memory, do not intentionally use non-maskable interrupts (the watchdog
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.
8. Execute the write command sequence.
9. Read the same flash memory address twice.
10. Set FLSCR<FLSMD> to "1100B" (to disable command sequence execution).
11. Jump to the flash memory area.
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.
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.
(Repeat step 7 until the same data is read by two consecutive read operations.)
(Repeat step 9 until the same data is read by two consecutive read operations.)
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