[Scope of application]
adviceXross, adviceLUNA II, adviceLUNA
[Question]
Is there any restriction when I do WIRED-OR the nTRST signal and nSRST signal?
[Answer]
We do not recommend you to do WIRED-OR the nTRST signal and nSRST signal.
[Information]
If nTRST signal and nSRST signal are WIRED-OR, JTAG communication is not available while nSRST is asserted, because nTRST is also asserted.
In such cases, ICE invokes a forced break by connecting the target by JTAG after releasing the assertion of nRST signal.
Therefore the following restrictions are applied.
- Cannot do the reset vector break even if you select the [Reset vector break]. (You can check the setting from [MPU] - [MPU-Specific settings] - [RESET])
- After releasing the assertion of nSRST, the target program is executed until the forced break is invoked.
- PC register is rewritten by 0 after the forced break is invoked if you select [Register to Set up Initial value]. (You can check the setting from [MPU] [MPU-specific settings]-[Reset].)
Therefore it looks a break occurred at address 0, but actually the target program is executing.
As a result, if you execute it from address 0, the initial processing of target program will be executed halfway, and then it will be reexecuted from address 0.