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ML66525 Family User’s Manual
Chapter 20
Flash Memory
20 - 1
20. Flash Memory
20.1 Overview
A flash ROM version of the ML66525 family devices is available. It is equipped with an
electrically programmable non-volatile memory (flash memory) as the internal program
memory. With three types of flash memory programming modes, the flash ROM version can
be programmed even after being installed in a system.
The flash ROM version available is the ML66Q525B, which operates on 2.4 to 3.6 V.
20.2 Features
Power supply voltage
ML66Q525B (2.4 to 3.6 V operation)
… Can be programmed with a single 2.4 to 3.6 V
power supply.
Programming modes
Flash memory has the following three programming modes.
Parallel mode … Can be programmed with a Minato Electronics’ PROM writer.
Serial mode
… Can be programmed with a flash memory writer.
User mode
… Can be programmed by program execution.
Programming blocks
Flash memory is programmed in blocks of 128-byte units.
Auto-erase function
Since an auto-erase function is provided to automatically erase the block to be written to prior
to programming, it is unnecessary to erase flash memory before programming.
Programming Time
Programming time for the flash memory is listed below.
Programming (128-byte unit) … Approx. 50 ms (at 2.4 to 3.6 V)
Write protect function
Flash memory has a built-in power-on write protect function that automatically disables
programming for approximately 20 ms after power is turned on.
In addition, there is an acceptor function to prevent incorrect programming in the user mode
due to a running of out-of-control program.
Security function
Flash memory has a built-in security function that disables reading of contents of memory
externally and/or programming externally. The security function is set in the serial mode, but
once the security function is set, contents of memory cannot be externally read from or
programming cannot be performed externally, in any programming mode.
The security function cannot be set in the parallel mode or in the user mode.