SAMA5D42_14 Datasheet, PDF (225/1776 Pages) ATMEL Corporation – Atmel | SMART ARM-based Embedded MPU

20.4.4 Reset State Priorities
The Reset State Manager manages the following priorities between the different reset sources, given in
descending order:
 Backup Reset
 Wake-up Reset
 Watchdog Reset
 Software Reset
 User Reset
Particular cases are listed below:
 When in User Reset:
̶ A watchdog event is impossible because the Watchdog Timer is being reset by the proc_nreset signal.
̶ A software reset is impossible, since the processor reset is being activated.
 When in Software Reset:
̶ A watchdog event has priority over the current state.
̶ The NRST has no effect.
 When in Watchdog Reset:
̶ The processor reset is active and so a Software Reset cannot be programmed.
̶ A User Reset cannot be entered.
20.4.5 Reset Controller Status Register
The Reset Controller Status Register (RSTC_SR) provides several status fields:
 RSTTYP field: This field gives the type of the last reset, as explained in previous sections.
 SRCMP bit: This bit indicates that a Software Reset Command is in progress and that no further software
reset should be performed until the end of the current one. This bit is automatically cleared at the end of the
current software reset.
 NRSTL bit: This bit gives the level of the NRST pin sampled on each MCK rising edge.
 URSTS bit: A high-to-low transition of the NRST pin sets the URSTS bit. This transition is also detected on
the Master Clock (MCK) rising edge (see Figure 20-8). If the User Reset is disabled (URSTEN = 0 in
RSTC_MR) and if the interruption is enabled by the URSTIEN bit in the RSTC_MR, the URSTS bit triggers
an interrupt. Reading the RSTC_SR resets the URSTS bit and clears the interrupt.
SAMA5D4 Series [DATASHEET]
Atmel-11238A-ATARM-SAMA5D4-Datasheet_30-Sep-14
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