SLAZ616AA August 2014 – August 2021 MSP430FR68891
GC Module
Functional
Nonexistent FRAM failures can be detected after wake-up from LPM 1/2/3/4
The FRAM bit error detection may indicate bit errors, even the memory has no failure, after wakeup from LPM1/2/3/4.
Based on the setting inside the FRAM controller registers (GCCTL0), following behaviors can appear.
1. Unexpected PUC for an uncorrectable FRAM error can be triggered and causing the corresponding value in the SYSRSTIV register.
This happens only if GCCTL0.UBDRSTEN =1.
2. Unexpected NMI for an uncorrectable FRAM error can be triggered and causing the corresponding value in the SYSSNIV register.
This happens only if the GCCTL0.UBDIE = 1.
3. Unexpected NMI for a correctable FRAM error can be triggered and causing the corresponding value in the SYSSNIV register.
This happens only if the GCCTL0.CBDIE =1.
1. Disable PUC (GCCTL0.UBDRSTEN=0), UBDIE and CBDIE interrupts (GCCTL0.UBDIE=0 and GCCTL0.CBDIE=0) prior to entering LPM 1/2/3/4.
2. After LPM wake up, clear GCCTL1.UBDIFG and GCCTL1.CBDIFG, and then reinitialize the GCCTL0 register after the first valid FRAM access has been completed. For the valid FRAM access the user has to consider possible cache hits which depends on implementation.