Other Parts Discussed in Thread: MSP-FET, CCSTUDIO
Tool/software: Code Composer Studio
MCU :MSP430F2274
CCS: 7.4.0.00015
Debugger: MSP-FET430UIF
Under Debug options, I do not have any of the "Disable interrupts" options checked.
Note:
1. Only software breakpoints cause this issue. Hardware breakpoints, which the MSP430F2274 only seems to have one available for user placement, do not cause any issues.
2. It is the act of placing the software breakpoint that clears the GIE. Once the software breakpoint is placed, if I manually set GIE to 1 the interrupts will resume triggering normally.
3. The software breakpoint must be placed while the program is outside the ISR in order for GIE to be cleared. If it is placed while the program is inside the ISR, the GIE is already 0 and will correctly return to 1 when the ISR returns (the value stored on the stack).
EDIT: Initially I thought the software breakpoint had to be placed inside the ISR in order for the problem to occur, but that is not the case. Placing a software breakpoint anywhere (while the program is outside an ISR, so the SR register is not backed up in the stack) will clear the GIE and prevent interrupts.