CHAPTER2: Flash Security
2. Operation Explanation
P E R I P H E R A L M A N U A L
August 31, 2015, S6E1Cx_MN710-00016-1v0-E
41
CONFIDENTIAL
2. Operation Explanation
This section explains the operation of the flash security.
Setting Security
Write the protection code 0x0001 in address of the security code. The security is enabled and set after all
the reset factors are generated or after turning on the power again.
Releasing Security
The security is released by all the reset factors or power-on after the execution of flash erase.
Operation with Security Enabled
The operations with security enabled vary depending on each mode.
Table 2-1 shows the security operations in each mode.
Table 2-1 Flash Operation with Security Enabled
Mode
Mode pin
{MD0,MD1 }
Access to flash
Access from
debugging pin
Flash erase
Other
commands
Read
User mode
{0,x}
Enabled
Enabled
Valid data
Disabled
Serial writer
mode
{1,0}
Enabled
Disabled
Invalid data
Disabled
Notes:
−
Writing the protection code is generally recommended to take place at the end of the flash
programming. This is to avoid unnecessary protection during the programming.
−
In user mode, there is no limit to the flash memory even during security is enabled. However,
debugging pins are fixed not to access internally from these pins during security is enabled. To
release security, perform the flash erase operation using a serial writer because the security cannot
be released through debugging pins.
−
When security enabled, the obstruction analysis of the flash memory cannot be performed.
−
x indicates any value.
