at91sam9263 ATMEL Corporation, at91sam9263 Datasheet - Page 113

• Manufacturer Part Number: at91sam9263
• Description: At91 Arm Thumb Microcontrollers
• Manufacturer: ATMEL Corporation

Figure 14-7. Software Reset
14.3.4.5
6249D–ATARM–20-Dec-07
SRCMP in RSTC_SR
Write RSTC_CR
Watchdog Reset
if PROCRST=1
periph_nreset
if PERRST=1
if EXTRST=1
proc_nreset
(nrst_out)
RSTTYP
NRST
SLCK
MCK
The internal reset signals are asserted as soon as the register write is performed. This is
detected on the Master Clock (MCK). They are released when the software reset is left, i.e.; syn-
chronously to SLCK.
If EXTRST is set, the nrst_out signal is asserted depending on the programming of the field
ERSTL. However, the resulting falling edge on NRST does not lead to a User Reset.
If and only if the PROCRST bit is set, the Reset Controller reports the software status in the field
RSTTYP of the Status Register (RSTC_SR). Other Software Resets are not reported in
RSTTYP.
As soon as a software operation is detected, the bit SRCMP (Software Reset Command in
Progress) is set in the Status Register (RSTC_SR). It is cleared as soon as the software reset is
left. No other software reset can be performed while the SRCMP bit is set, and writing any value
in RSTC_CR has no effect.
The Watchdog Reset is entered when a watchdog fault occurs. This state lasts Y Slow Clock
cycles.
When in Watchdog Reset, assertion of the reset signals depends on the WDRPROC bit in
WDT_MR:
• If WDRPROC is 0, the Processor Reset and the Peripheral Reset are asserted. The NRST
line is also asserted, depending on the programming of the field ERSTL. However, the
resulting low level on NRST does not result in a User Reset state.
Freq.
Any
Any
Resynch.
1 cycle
Processor Startup
XXX
= 3 cycles
EXTERNAL RESET LENGTH
8 cycles (ERSTL=2)
AT91SAM9263 Preliminary
0x3 = Software Reset
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