Document # 001-20559 Rev. *D
35
Sleep and Watchdog
12.3.4
CPU_SCR0 Register
The System Status and Control Register 0 (CPU_SCR0) is
used to convey the status and control of events for various
functions of the PSoC device.
Bit 7: GIES.
The Global Interrupt Enable Status bit is a
read only status bit and its use is discouraged. The GIES bit
is a legacy bit which was used to provide the ability to read
the GIE bit of the CPU_F register. However, the CPU_F reg-
ister is now readable. When this bit is set, it indicates that
the GIE bit in the CPU_F register is also set which, in turn,
indicates that the microprocessor services interrupts.
Bit 5: WDRS.
The WatchDog Reset Status bit may not be
set. It is normally ‘0’ and automatically set whenever a
watchdog reset occurs. The bit is readable and clearable by
writing a zero to its bit position in the CPU_SCR0 register.
Bit 4: PORS.
The Power On Reset Status (PORS) bit,
which is the watchdog enable bit, is set automatically by a
POR or External Reset (XRES). If the bit is cleared by user
code, the watchdog timer is enabled. Once cleared, the only
way to reset the PORS bit is to go through a POR or XRES.
Thus, there is no way to disable the watchdog timer, other
than to go through a POR or XRES.
Bit 3: Sleep.
The Sleep bit is used to enter Low Power
Sleep mode when set. To wake up the system, this register
bit is cleared asynchronously by any enabled interrupt.
There are two special features of this register bit that
ensures proper sleep operation. First, the write to set the
register bit is blocked, if an interrupt is about to be taken on
that instruction boundary (immediately after the write). Sec-
ond, there is a hardware interlock to ensure that, once set,
the Sleep bit may not be cleared by an incoming interrupt
until the sleep circuit has finished performing the sleep
sequence and the system-wide power down signal has been
asserted. This prevents the sleep circuit from being inter-
rupted in the middle of the process of system power down,
possibly leaving the system in an indeterminate state.
Bit 0: STOP.
The STOP bit is readable and writeable.
When set, the PSoC M8C stops executing code until a reset
event occurs. This can be either a POR or WDR, or XRES. If
an application wants to stop code execution until a reset, the
preferred method is to use the HALT instruction rather than
a register write to this bit.
For additional information, refer to the
Address
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Access
x,FFh
GIES
WDRS
PORS
Sleep
STOP
# : XX
LEGEND
X
The value for power on reset is unknown.
x
An “x” before the comma in the address field indicates that this register can be read or written to no matter what bank is used.
#
Access is bit specific. Refer to register detail for additional information.
Summary of Contents for PSoC CY8C23533
Page 4: ...Contents Overview 4 Document 001 20559 Rev D Section G Glossary 385 Index 401 ...
Page 16: ...Contents Overview 16 Document 001 20559 Rev D ...
Page 24: ...24 Document 001 20559 Rev D Section A Overview ...
Page 30: ...30 Document 001 20559 Rev D Pin Information ...
Page 54: ...54 Document 001 20559 Rev D Supervisory ROM SROM ...
Page 60: ...60 Document 001 20559 Rev D RAM Paging ...
Page 68: ...68 Document 001 20559 Rev D Interrupt Controller ...
Page 76: ...12 Document 001 20559 Rev D General Purpose IO GPIO ...
Page 82: ...18 Document 001 20559 Rev D Internal Main Oscillator IMO ...
Page 84: ...20 Document 001 20559 Rev D Internal Low Speed Oscillator ILO ...
Page 90: ...26 Document 001 20559 Rev D External Crystal Oscillator ECO ...
Page 94: ...30 Document 001 20559 Rev D Phase Locked Loop PLL ...
Page 106: ...42 Document 001 20559 Rev D Sleep and Watchdog ...
Page 228: ...164 Document 001 20559 Rev D Section D Digital System ...
Page 234: ...170 Document 001 20559 Rev D Array Digital Interconnect ADI ...
Page 278: ...214 Document 001 20559 Rev D Digital Blocks ...
Page 296: ...232 Document 001 20559 Rev D Analog Interface ...
Page 304: ...240 Document 001 20559 Rev D Analog Array ...
Page 308: ...244 Document 001 20559 Rev D Analog Input Configuration ...
Page 312: ...248 Document 001 20559 Rev D Analog Reference ...
Page 338: ...274 Document 001 20559 Rev D Section F System Resources ...
Page 354: ...290 Document 001 20559 Rev D Multiply Accumulate MAC ...
Page 374: ...310 Document 001 20559 Rev D I2C ...
Page 400: ...336 Document 001 20559 Rev D Section G Glossary ...