TXZ Family
Flash Memory
2018-06-05
62 / 120
Rev. 2.0
4.1.7. Security Function
The security function can disable data reading from the flash writer, and disable the debug function.
4.1.7.1. Security Setting
In order to enable a security function, a security bit is set to “1” by a security bit program command.
The security function is enabled under the following conditions:
1.
[FCSBMR]
<SMB>=1
2.
Security bit =1
Note: After security bit writing, security is enabled by system reset.
4.1.7.2. Security Setting Release
To release the security function, perform the procedure below:
1.
[FCSBMR]
<SMB>=0
2.
Set “0” to the security bit with the security bit erasing command.
While
[FCSBMR]
<SMB>=1 and
[FCSSR]
<SEC>=1, if the security bit erasing command is executed, the chip
erasing function is executed, and then code flash, data flash, and security bits are erased.
4.1.7.3. Operation
Table 4.3 shows the flash memory operation when the security function is enabled.
Table 4.3 Flash memory operation when the security function is enabled
Parameter
Description
Flash memory reading
Reading from the CPU is possible.
Debug mode
Debugging is disabled.
Flash writer mode
Flash memory cannot be read/wrte.