
ML66517 Family User’s Manual
Chapter 18
Flash Memory
18 – 1
18. Flash Memory
18.1 Overview
The ML66Q517, a member of the ML66517 family devices, 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 ML66Q517 can be programmed even after being installed in a system.
18.2 Features
Power supply voltage
Can be programmed with a single 4.5 to 5.5 V power supply
Programming modes
Flash memory has the following three programming modes.
Parallel mode … Can be programmed with a PROM writer of MINATO ELECTRONICS make
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 units) … Approx. 40 ms (at 4.5 to 5.5 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 user mode.