Alternate Event Generation - STMicroelectronics SPC572L series Reference Manual

RM0400
Note: The RGM_FERD register can be written only once between two power-on reset events.
An enabled 'functional' reset normally triggers a reset sequence starting from the beginning
of PHASE1. Nevertheless, the RGM_FESS register enables the further configuring of the
reset sequence triggered by a 'functional' reset. When RGM_FESS.SS_<functional reset>
is set, the associated 'functional' reset triggers a reset sequence starting directly from the
beginning of PHASE3, skipping PHASE1 and PHASE2. This can be useful especially in
case a 'functional' reset should not reset the flash module.
51.4.5

Alternate event generation

The MC_RGM provides alternative events to be generated on reset source assertion. when
a reset source is asserted, the MC_RGM normally enters the reset sequence. Alternatively,
it is possible for some reset source events to be converted from a reset to either a SAFE
mode request issued to the MC_ME or to an interrupt request issued to the core.
Alternate event selection for a given reset source is made via the RGM_DERD/FERD and
RGM_DEAR/FEAR registers as shown in
RGM_D/FERD
The alternate event is cleared by deasserting the source of the request (i.e., at the reset
source that caused the alternate request) and also clearing the appropriate RGM_D/FES
status bit.
• SAFE mode requests are generated regardless of whether the system clock is running.
Interrupt requests are generated with the system clock, and therefore, if the system clock was
disabled at the time of the event, the interrupt request is not asserted until the system clock
is re-enabled.RGM_TIMING
• If a masked 'destructive' reset event which is configured to generate a SAFE
mode/interrupt request occurs during PHASE0, it is ignored, and the MC_RGM will not send
any safe mode/interrupt request to the MC_ME.
• If a masked 'functional' reset event which is configured to generate a SAFE
mode/interrupt request occurs during PHASE1, it is ignored and the MC_RGM does not send
any safe mode/interrupt request to the MC_ME.
51.4.6 'Functional' reset escalation
'Functional' reset escalation can be used to generate a 'destructive' reset if a number of
'functional' or external resets has occurred between software writes to the RGM_FRET
register. This function is enabled by writing a non-zero value to the FRET field of this
register.
Once 'functional' reset escalation has been enabled, the MC_RGM increases a counter on
each 'functional' or external reset which causes a reset sequence to be initiated (i.e.,
entrance into PHASE1 or PHASE3 from the IDLE phase). This counter is cleared on a write
of any value to the RGM_FRET register and on any power-on or 'destructive' reset. If the
Table 872. MC_RGM Alternate Event Selection
bit value
0
1
1
DocID027809 Rev 4
Reset Generation Module (MC_RGM)
Table 872.
RGM_D/FEAR
bit value
X Reset
0 SAFE mode request
1 Interrupt request
Generated event
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