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Document # 001-20559 Rev. *D
Sleep and Watchdog
12.4
Timing Diagrams
12.4.1
Sleep Sequence
The Sleep bit, in the CPU_SCR0 register, is an input into the
sleep logic circuit. This circuit is designed to sequence the
device into and out of the hardware sleep state. The hard-
ware sequence to put the device to sleep is shown in
and is defined as follows.
1. Firmware sets the Sleep bit in the CPU_SCR0 register.
The Bus Request (BRQ) signal to the CPU is immedi-
ately asserted: This is a request by the system to halt
CPU operation at an instruction boundary.
2. The CPU issues a Bus Request Acknowledge (BRA) on
the following
of the CPU clock.
3. The sleep logic waits for the following
the CPU clock and then asserts a system-wide Power
Down (PD) signal. In
, the CPU is halted and
the system-wide power down signal is asserted.
The system-wide PD signal controls three major circuit
blocks: the Flash memory module, the Internal Main Oscilla-
tor (24/48 MHz oscillator that is also called the IMO), and
the bandgap voltage reference. These circuits transition into
a zero power state. The only operational circuits on the
PSoC device are the ILO (or optional ECO), the bandgap
refresh circuit, and the supply voltage monitor circuit. Note
that the system sleep state does not apply to the analog
array. Power down settings for individual analog blocks and
references must be done in firmware, prior to executing the
sleep instruction.
Figure 12-1. Sleep Sequence
IOW
SLEEP
BRQ
BRA
PD
On the falling edge of
CPUCLK, PD is asserted.
The 24/48 MHz system clock
is halted; the Flash and
bandgap are powered down.
CPUCLK
CPU captures
BRQ on next
CPUCLK edge.
Firmware write to
the SLEEP bit
causes an
immediate BRQ.
CPU
responds
with a BRA.
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 ...