TMP92FD54AI datasheet(53/84 Pages) TOSHIBA

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92FD54AI-53

2006-01-27

TMP92FD54AI

4.4

Programming/Erasing Flash Memory during on-Board Programming

The method used for controlling flash memory commands complies with JEDEC

standards for standard E2PROMs. For this reason, during RAM transfer operations in

User Boot Mode or Single Boot Mode the flash memory is programmed/erased by software

commands executed by the CPU. The program for controlling this program/erase operation

must be written in advance by the user. Because the flash memory cannot be read while it

is being programmed or erased, the program/erase control program must be placed in and

executed from the internal RAM or external memory after the device has entered User

Boot Mode or after a RAM transfer.

4.4.1

Flash memory

With a few exceptions, the functions for programming and erasing the flash memory

are based on JEDEC-compliant commands. To program or erase the flash memory,

enter a command to the flash memory using the CPU’s LD instruction. When a

command is entered, the flash memory will automatically be programmed or erased

internally. Furthermore, to erase the flash memory, several different methods can be

used: all the blocks can be erased together, each block can be erased individually.

Table 4.4.1 Flash memory functions

Main Functions

Description

Auto Program

Automatically writes data and verifies written data in long word units.

Auto Chip Erase

Automatically erases and verifies all the blocks of the flash memory together.

Auto Block Erase

Automatically erases and verifies in units of blocks.

Hardware Sequence flags

Monitoring flags such as a data polling or Toggle Bit flag help to confirm whether the flash memory is

being programmed or erased.

Block Protect

Block Protect function prevents individual blocks of flash memory from being programmed or erased.

As will be described later, in User Boot Mode or during RAM transfer the method of

address specification for operation commands differs from that for standard commands

for reasons of interfacing with the CPU. Also, unless otherwise stated, the flash

memory is written to in units of 32 bits. When writing to flash memory, use 32-bit (long

word) data transfer instructions. To enter commands, byte (8-bit) transfer instructions

can be used.

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