tmp88f846ug TOSHIBA Semiconductor CORPORATION, tmp88f846ug Datasheet - Page 195

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

18.3 Toggle Bit (D6)
18.4 Access to the Flash Memory Area
18.4.1 Flash Memory Control in the Serial PROM Mode
read from the same address is reversed bit 6 (D6) of the data (toggling between 0 and 1) until the operation is com-
pleted. Therefore, this toggle bit provides a software mechanism to check the completion of each operation. Usually
perform read operations repeatedly for data polling until the same data is read twice from the same address in the
flash memory. After the byte program, chip erase, or read protect command sequence is executed, the initial read of
the toggle bit always produces a "1".
formed in the entire flash memory area. Therefore, to perform these operations in the entire flash memory area,
access to the flash memory area by the control program in the BOOTROM or RAM area. (The flash memory pro-
gram cannot write to the flash memory.) The serial PROM or MCU mode is used to run the control program in the
BOOTROM or RAM area.
18.4.1.1 How to write to the flash memory by executing the control program in the RAM area (in
After the byte program, chip erase, and read protect command sequence is executed, any consecutive attempts to
When the write, erase and read protections are set in the flash memory, read and fetch operations cannot be per-
Note 1: The flash memory can be written or read for each byte unit. Erase operations can be performed either in the entire
Note 2: To rewrite data to Flash memory addresses at which data (including FFH) is already written, make sure to erase
BOOTROM area. Since almost of all operations relating to access to the flash memory can be controlled sim-
ply by the communication data of the serial interface (UART), these functions are transparent to the user. For
the details of the serial PROM mode, see “Serial PROM Mode.”
command to execute the control program in the RAM area. The procedures to execute the control program in
the RAM area is shown in " 18.4.1.1 How to write to the flash memory by executing the control program in the
RAM area (in the RAM loader mode within the serial PROM mode) ".
To access to the flash memory by using peripheral functions in the serial PROM mode, run the RAM loader
The serial PROM mode is used to access to the flash memory by the control program provided in the
area or in units of 4 kbytes, whereas read operations can be performed by an one transfer instruction. However,
the command sequence method is adopted for write and erase operations, requiring several-byte transfer instruc-
tions for each operation.
the existing data by "sector erase" or "chip erase" before rewriting data.
the RAM loader mode within the serial PROM mode)
executed in the RAM area.)
(Steps 1 and 2 are controlled by the BOOTROM, and steps 3 to 9 are controlled by the control program
Note 1: Before writing to the flash memory in the RAM area, disable interrupts by setting the interrupt master
1. Transfer the write control program to the RAM area in the RAM loader mode.
2. Jump to the RAM area.
3. Disable (DI) the interrupt master enable flag (IMF←"0").
4. Set FLSCR<FLSMD> to "0011B" (to enable command sequence execution).
5. Execute the erase command sequence.
6. Read the same flash memory address twice.
7. Execute the write command sequence.
8. Read the same flash memory address twice.
9. Set FLSCR<FLSMD> to "1100B" (to disable command sequence execution).
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.
(Repeat step 8 until the same data is read by two consecutive reads operations.)
(Repeat step 6 until the same data is read by two consecutive reads operations.)
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