69rlq62d-f714peg4 * Memec (Headquar
ter
s) - Unique
Tec
h,
Insight,
Impact
MAR
VELL CONFIDENTIAL,
UNDER ND
A# 12101050
69rlq62d-f714peg4 * Memec (Headquar
ter
s) - Unique
Tec
h,
Insight,
Impact
MAR
VELL CONFIDENTIAL,
UNDER ND
A# 12101050
69r
lq62d-f714peg4 * Memec (Headquar
ters) - Unique
T
ech, Insight, Impact * UNDER ND
A# 12101050
MAR
VELL CONFIDENTIAL - UNA
UTHORIZED DISTRIB
UTION OR USE STRICTL
Y PR
OHIBITED
Services Power Management Unit
Copyright © 12/13/06 Marvell
CONFIDENTIAL
Doc. No. MV-TBD-00 Rev. A
December 13, 2006
Document Classification: Proprietary Information
Page 191
Not approved by Document Control. For review only.
8.6.5
Watchdog Reset
The watchdog reset is invoked when software fails to properly prevent the watchdog time-out event from
occurring for that timer. The watchdog reset from within the PXA300 processor is the watchdog reset and is
output to the entire processor architecture and causes a reset the same as if a hardware reset had been asserted
except for those modules listed in
.
8.6.5.1
Invoking Watchdog Reset
Watchdog reset is invoked when the WME bit in the “OS Timer Watchdog Match Enable register (OWER)” in
the timer module, and the “OS Timer Match register 3 (OSMR3)” matches the OS timer counter. The OS counter
for channel 3 only increments in S0/D0/C0, S0/D0/C1 and S0/D0CS modes. A watchdog reset cannot occur in
S0/D1/C2, S0/D2/C2, S2/D3/C4 or S3/D4/C4.
When this event occurs, watchdog reset is entered regardless of the previous mode. When watchdog reset is
invoked, the entire processor reset is asserted except to the units as shown in
, resetting the services
unit, application subsystem, and the pad unit. Additionally, all pins assume their reset states, including SYS_EN
which is negated.
The sequence for watchdog reset is:
1. The PXA300 processor OS timer asserts watchdog reset (OSMR3 matches the OS timer counter.)
2. The PXA300 processor OS timer watchdog reset is reset automatically as a result of propagation of the
internal application-subsystem reset state, and the services unit, and the pad unit are reset.
3. The reset is de-asserted.
The hardware reset sequence is executed by the services unit, and normal boot-up sequencing begins for the
application subsystem, with all units starting with their predefined reset state. The application core software must
examine the “Application Subsystem Reset Status register (ARSR)” to determine that the reset source was a
watchdog reset.
8.6.6
Summary of Module Reset Sensitivity
The registers and functions of most modules take their default, or reset, value when entering any of the five reset
modes. The exceptions to this are listed in
Table 8-2. Summary of Module Reset Functions (Sheet 1 of 2)
Services
Unit Module
Register Name or Function
L
o
w-
P
o
we
r
S
tate E
x
it
GP
IO
Gl
o
b
a
l
W
a
tc
hdo
g
Ha
rd
w
a
re
P
o
we
r-
On
PWR_I
2
C
All registers and functions including PVCR
x
†
x
x
x
RTC
RTTR
x
x
RTC
Other registers and functions
x
x
x
MPMU
JCONR, All bits in PMCR except BIE and BIS
x
†
x
x
x
MPMU
PSR, PSPR, PCFR, PWER, PWSR, PECR, and BIE and BIS in PMCR
x
x
x
MPMU
DCSR
x