How is on-chip debug option byte set for program in mass-production?
Question:
Answer:
The setting of "On-chip debug operation disabled" by the on-chip debug option byte is not sufficient from the point of ensuring security, such as preventing a third party from tampering with the program. The security of the microcontroller has to be set separately.
The operations determined by the combination of the on-chip debugger operation setting by the on-chip debug option byte and security setting of the microcontroller are shown below.
Change the settings appropriately to match the situation in which they are used.
| On-chip debug option byte is set to "Disabling on-chip debugger operation" (*Note 1) | On-chip debug option byte is set to "Enabling on-chip debugger operation" (*Note 2) | |
| Microcontroller has a security setting | Reading or writing by a third party can be completely prohibited by the security setting of the microcontroller. |
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| Microcontroller has no security setting |
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*Note 1
The on-chip debug security ID is to be input when the on-chip debugger is started up. Therefore, as long as "Disabling on-chip debugger operation" is set, the on-chip debug security ID setting is irrelevant.
*Note 2
Since the on-chip debug security ID must be matched to start up the on-chip debugger, a certain level of security can be ensured by setting a unique on-chip debug security ID.
*Note 3
There is a possibility that the on-chip debug option byte or security ID might be rewritten.
| RL78 Family |
| CS+ (formerly CubeSuite+) |
| E1 [R0E000010KCE00] |
| E20 [R0E000200KCT00] |