Table of Contents
Advertisement
20.5
Protection
There are three kinds of flash memory program/erase protection: hardware, software, and error
protection.
20.5.1
Hardware Protection
Programming and erasing of flash memory is forcibly disabled or suspended by hardware
protection. In this state, the downloading of an on-chip program and initialization are possible.
However, an activated program for programming or erasure cannot program or erase the user
MAT, and the error in programming/erasing is reported in the parameter FPFR.
Table 20.9 Hardware Protection
Item
Description
•
FWE pin
When a low level signal is input to the FWE
protection
pin, the FWE bit in FCCS is cleared and the
program/erase-protected state is entered.
•
Reset/standby
The program/erase interface registers are
protection
initialized by a reset (including a reset by the
WDT) and in hardware standby mode and
the program/erase-protected state is
entered.
•
The reset state will not be entered by a reset
using the RES pin unless the RES pin is held
low until oscillation has stabilized after power
is initially supplied. In the case of a reset
during operation, hold the RES pin low for
the RES pulse width that is specified in the
section on AC characteristics. If a reset is
input during programming or erasure, data
values in the flash memory are not
guaranteed. In this case, execute erasure
and then execute programming again.
Rev. 1.00, 09/03, page 578 of 704
Function to be Protected
Download
Program/Erase
Advertisement
Table of Contents
