Component - CyBoot V4.11 Datasheet.pdf

PSoC® Creator™
System Reference Guide
cy_boot Component v4.11
Document Number: 001-94480, Rev. **
Cypress Semiconductor
198 Champion Court
San Jose, CA 95134-1709
Phone (USA): 800.858.1810
Phone (Intl): 408.943.2600
http://www.cypress.com
Copyrights
© Cypress Semiconductor Corporation, 2014. The information contained herein is subject to change
without notice. Cypress Semiconductor Corporation assumes no responsibility for the use of any
circuitry other than circuitry embodied in a Cypress product. Nor does it convey or imply any license
under patent or other rights. Cypress products are not warranted nor intended to be used for medical,
life support, life-saving, critical control or safety applications, unless pursuant to an express written
agreement with Cypress. Furthermore, Cypress does not authorize its products for use as critical
components in life-support systems where a malfunction or failure may reasonably be expected to result
in significant injury to the user. The inclusion of Cypress products in life-support systems application
implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress against
all charges.
®
PSoC is a registered trademark, and PSoC Creator™ and Programmable System-on-Chip™ are
trademarks of Cypress Semiconductor Corp. All other trademarks or registered trademarks referenced
herein are property of the respective corporations.
Any Source Code (software and/or firmware) is owned by Cypress Semiconductor Corporation
(Cypress) and is protected by and subject to worldwide patent protection (United States and foreign),
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personal, non-exclusive, non-transferable license to copy, use, modify, create derivative works of, and
compile the Cypress Source Code and derivative works for the sole purpose of creating custom
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compilation, or representation of this Source Code except as specified above is prohibited without the
express written permission of Cypress.
Disclaimer: CYPRESS MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH
REGARD TO THIS MATERIAL, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. Cypress reserves the right
to make changes without further notice to the materials described herein. Cypress does not assume any
liability arising out of the application or use of any product or circuit described herein. Cypress does not
authorize its products for use as critical components in life-support systems where a malfunction or
failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress’
product in a life-support systems application implies that the manufacturer assumes all risk of such use
and in doing so indemnifies Cypress against all charges.
Use may be limited by and subject to the applicable Cypress software license agreement.
PSoC® Creator™ System Reference Guide, Document Number: 001-94480, Rev. **
2
Contents
1
Introduction .................................................................................................................................... 5
Conventions ............................................................................................................................... 6
References ................................................................................................................................ 6
Sample Firmware Source Code ................................................................................................ 6
Revision History ......................................................................................................................... 6
2
Standard Types and Defines ......................................................................................................... 7
Base Types ................................................................................................................................ 7
Hardware Register Types .......................................................................................................... 7
Compiler Defines ....................................................................................................................... 7
Keil 8051 Compatibility Defines ................................................................................................. 8
Return Codes............................................................................................................................. 8
Interrupt Types and Macros ....................................................................................................... 9
Intrinsic Defines ......................................................................................................................... 9
Device Version Defines ............................................................................................................. 9
Variable Attributes ...................................................................................................................... 9
PSoC Creator Generated Defines ........................................................................................... 10
3
Clocking ........................................................................................................................................ 13
PSoC Creator Clocking Implementation .................................................................................. 13
APIs ......................................................................................................................................... 24
4
Power Management ..................................................................................................................... 37
PSoC 3/PSoC 5LP Implementation ......................................................................................... 37
PSoC 4 Implementation ........................................................................................................... 46
Instance Low Power APIs ........................................................................................................ 49
5
Interrupts....................................................................................................................................... 51
APIs ......................................................................................................................................... 51
6
Pins ................................................................................................................................................ 55
PSoC 3/PSoC 5LP APIs .......................................................................................................... 55
PSoC 4 APIs ............................................................................................................................ 57
7
Register Access ........................................................................................................................... 59
APIs ......................................................................................................................................... 59
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Contents
8
DMA ............................................................................................................................................... 63
9
Flash and EEPROM ...................................................................................................................... 65
PSoC 3/PSoC 5LP Implementation ......................................................................................... 65
PSoC 4 Implementation ........................................................................................................... 73
10
Bootloader Migration ................................................................................................................... 77
Introduction .............................................................................................................................. 77
Migrating Bootloader Designs ................................................................................................. 78
Migrating Bootloadable Designs .............................................................................................. 79
Project Application Type Property Changes ............................................................................ 79
Migrating Bootloadable Dependency to Bootloader Design .................................................... 79
11
System Functions ........................................................................................................................ 81
General APIs............................................................................................................................ 81
CyDelay APIs ........................................................................................................................... 82
PSoC 3/PSoC 5LP Voltage Detect APIs.................................................................................. 83
PSoC 4100 and 4200 Voltage Detect APIs ............................................................................. 87
Cache Functionality ................................................................................................................. 88
12
Startup and Linking...................................................................................................................... 89
PSoC 3 .................................................................................................................................... 90
PSoC 4/PSoC 5LP .................................................................................................................. 90
Preservation of Reset Status ................................................................................................... 93
13
Watchdog Timer ........................................................................................................................... 95
PSoC 3/PSoC 5LP .................................................................................................................. 95
PSoC 4100 and PSoC 4200 .................................................................................................... 96
PSoC 4000 ............................................................................................................................ 103
14
MISRA Compliance .................................................................................................................... 109
Verification Environment ........................................................................................................ 109
Project Deviations .................................................................................................................. 110
Documentation Related Rules ................................................................................................ 111
PSoC Creator Generated Sources Deviations ...................................................................... 112
cy_boot Component-Specific Deviations ............................................................................... 113
15
cy_boot Component Changes .................................................................................................. 115
Version 4.11 ........................................................................................................................... 115
Version 4.10 ........................................................................................................................... 115
Version 4.0 ............................................................................................................................. 116
Version 3.40 and Older .......................................................................................................... 117
Version 2.40 and Older .......................................................................................................... 120
PSoC® Creator™ System Reference Guide, Document Number: 001-94480, Rev. **
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1
Introduction
This System Reference Guide describes functions supplied by the PSoC Creator cy_boot component.
The cy_boot component provides the system functionality for a project to give better access to chip
resources. The functions are not part of the component libraries but may be used by them. You can use
the function calls to reliably perform needed chip functions.
The cy_boot component is unique:

Included automatically into every project

Only a single instance can be present

No symbol representation

Not present in the Component Catalog (by default)
As the system component, cy_boot includes various pieces of library functionality. This guide is organized
by these functions:

DMA (unavailable for PSoC 4)

Flash

Clocking

Power management

Startup code

Various library functions

Linker scripts
The cy_boot component presents an API that enables user firmware to accomplish the tasks described in
this guide. There are multiple major functional areas that are described separately.
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Introduction
Conventions
The following table lists the conventions used throughout this guide:
Convention
Usage
Courier New
Displays file locations and source code:
C:\ …cd\icc\, user entered text
Displays file names and reference documentation:
sourcefile.hex
Displays keyboard commands in procedures:
[Enter] or [Ctrl] [C]
Represents menu paths:
File > New Project > Clone
Displays commands, menu paths and selections, and icon names in
procedures:
Click the Debugger icon, and then click Next.
Displays cautions or functionality unique to PSoC Creator or the PSoC device.
Italics
[bracketed, bold]
File > New Project
Bold
Text in gray boxes
References
This guide is one of a set of documents pertaining to PSoC Creator and PSoC devices. Refer to the
following other documents as needed:

PSoC Creator Help

PSoC Creator Component Datasheets

PSoC Creator Component Author Guide

PSoC Technical Reference Manual (TRM)
Sample Firmware Source Code
PSoC Creator provides numerous example projects that include schematics and example code in the
Find Example Project dialog. For component-specific examples, open the dialog from the Component
Catalog or an instance of the component in a schematic. For general examples, open the dialog from the
Start Page or File menu. As needed, use the Filter Options in the dialog to narrow the list of projects
available to select.
Refer to the “Find Example Project” topic in the PSoC Creator Help for more information.
Revision History
Document Title: PSoC® Creator™ System Reference Guide, cy_boot Component v4.11
Document Number: 001-94480
Revision
Date
Description of Change
**
9/30/14
New document for version 4.11 of the cy_boot component. Refer to the change
section for component changes from previous versions of cy_boot.
PSoC® Creator™ System Reference Guide, Document Number: 001-94480, Rev. **
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2
Standard Types and Defines
To support the operation of the same code across multiple CPUs with multiple compilers, the cy_boot
component provides types and defines that create consistent results across platforms.
Base Types
Type
Description
char8
uint8
uint16
uint32
int8
int16
int32
float32
float64
int64
uint64
8-bit (signed or unsigned, depending on the compiler selection for char)
8-bit unsigned
16-bit unsigned
32-bit unsigned
8-bit signed
16-bit signed
32-bit signed
32-bit float
64-bit float (unavailable for PSoC 3)
64-bit signed (unavailable for PSoC 3)
64-bit unsigned (unavailable for PSoC 3)
Hardware Register Types
Hardware registers typically have side effects and therefore are referenced with a volatile type.
Define
Description
reg8
reg16
reg32
Volatile 8-bit unsigned
Volatile 16-bit unsigned
Volatile 32-bit unsigned
Compiler Defines
The compiler being used can be determined by testing for the definition of the specific compiler. For
example, to test for the PSoC 3 Keil compiler:
#if defined(__C51__)
Define
Description
__C51__
__GNUC__
__ARMCC_VERSION
Keil 8051 compiler
ARM GCC compiler
ARM Realview compiler used by Keil MDK and RVDS tool sets
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Standard Types and Defines
Keil 8051 Compatibility Defines
The Keil 8051 compiler supports type modifiers that are specific to this platform. For other platforms these
modifiers must not be present. For compatibility these types are supported by defines that map to the
appropriate string when compiled for Keil and an empty string for other platforms. These defines are used
to create optimized Keil 8051 code while still supporting compilation on other platforms.
Define
Keil Type
CYBDTA
CYBIT
CYCODE
CYCOMPACT
CYDATA
CYFAR
CYIDATA
CYLARGE
CYPDATA
CYREENTRANT
CYSMALL
CYXDATA
bdata
bit
code
compact
data
far
idata
large
pdata
reentrant
small
xdata
Other Platforms
uint8
Return Codes
Return codes from Cypress routines are returned as an 8-bit unsigned value type: cystatus. The standard
return values are:
Define
Description
CYRET_SUCCESS
CYRET_UNKNOWN
CYRET_BAD_PARAM
CYRET_INVALID_OBJECT
CYRET_MEMORY
CYRET_LOCKED
CYRET_EMPTY
CYRET_BAD_DATA
CYRET_STARTED
CYRET_FINISHED
CYRET_CANCELED
CYRET_TIMEOUT
CYRET_INVALID_STATE
Successful
Unknown failure
One or more invalid parameters
Invalid object specified
Memory related failure
Resource lock failure
No more objects available
Bad data received (CRC or other error check)
Operation started, but not necessarily completed yet
Operation completed
Operation canceled
Operation timed out
Operation not setup or is in an improper state
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Standard Types and Defines
Interrupt Types and Macros
Types and macros provide consistent definition of interrupt service routines across compilers and
platforms. Note that the macro to use is different between the function definition and the function
prototype.
Function definition example:
CY_ISR(MyISR)
{
/* ISR Code here */
}
Function prototype example:
CY_ISR_PROTO(MyISR);
Interrupt vector address type
Type
Description
cyisraddress
Interrupt vector (address of the ISR function)
Intrinsic Defines
Define
Description
CY_NOP
Processor NOP instruction
Device Version Defines
Define
CY_PSOC3
CY_PSOC5
CY_PSOC4
Description
Any PSoC 3 Device
Any PSoC 5 Device
PSoC 4 Device
Variable Attributes
Define
Description
CY_NOINIT
Specifies that a static variable should be placed into uninitialized data section that
prevents this variable from being initialized to zero on startup.
For PSoC 3 no code is generated for this macro.
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Standard Types and Defines
PSoC Creator Generated Defines
Project Type
The following are defines for project type (from Project > Build Settings):

CYDEV_PROJ_TYPE

CYDEV_PROJ_TYPE_BOOTLOADER

CYDEV_PROJ_TYPE_LOADABLE

CYDEV_PROJ_TYPE_MULTIAPPBOOTLOADER

CYDEV_PROJ_TYPE_STANDARD
Chip Configuration Mode
The following are defines for chip configuration mode (from System DWR). Options vary by device:
All

CYDEV_CONFIGURATION_MODE

CYDEV_CONFIGURATION_MODE_COMPRESSED

CYDEV_CONFIGURATION_MODE_DMA

CYDEV_CONFIGURATION_MODE_UNCOMPRESSED

CYDEV_DEBUGGING_ENABLE or
CYDEV_PROTECTION_ENABLE (Debugging or protection enabled. Mutually exclusive.)
PSoC 3

CYDEV_CONFIGURATION_CLEAR_SRAM (Startup code clear SRAM?)
PSoC 3 and PSoC 5LP

CYDEV_CONFIGURATION_COMPRESSED (Configuration data compressed?)

CYDEV_CONFIGURATION_DMA (Configuration data loaded via DMA?)

CYDEV_CONFIGURATION_ECC (Configuration data stored in ECC?)

CYDEV_CONFIG_FASTBOOT_ENABLED (Device startup at 48 MHz at boot? If not, 12 MHz.)

CYDEV_INSTRUCT_CACHE_ENABLED (Instruction cache enabled?)

CYDEV_DMA_CHANNELS_AVAILABLE (Number of DMA channels available for configuration.)

CYDEV_ECC_ENABLE (ECC enabled?)

CYDEV_DEBUGGING_XRES (Optional XRES pin enabled as XRES?)
PSoC 4

CYDEV_CONFIG_READ_ACCELERATOR (Flash read accelerator enabled?)
PSoC 4 and PSoC 5LP

CYDEV_USE_BUNDLED_CMSIS (Include the CMSIS standard library.)
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Standard Types and Defines
Debugging Mode
The following are defines for debugging mode (from System DWR):

CYDEV_DEBUGGING_DPS

CYDEV_DEBUGGING_DPS_Disable

CYDEV_DEBUGGING_DPS_JTAG_4

CYDEV_DEBUGGING_DPS_JTAG_5

CYDEV_DEBUGGING_DPS_SWD

CYDEV_DEBUGGING_DPS_SWD_SWV
Chip Protection Mode
The following are defines for chip protection mode (from System DWR):

CYDEV_DEBUG_PROTECT

CYDEV_DEBUG_PROTECT_KILL

CYDEV_DEBUG_PROTECT_OPEN

CYDEV_DEBUG_PROTECT_PROTECTED
Stack and Heap
The following are defines for the number of bytes allocated to the stack and heap (from System DWR).
These are only for PSoC 4 and PSoC 5LP.

CYDEV_HEAP_SIZE

CYDEV_STACK_SIZE
Voltage Settings
The following are defines for voltage settings (from System DWR). Options vary by device:

CYDEV_VARIABLE_VDDA

CYDEV_VDDA

CYDEV_VDDA_MV

CYDEV_VDDD

CYDEV_VDDD_MV

CYDEV_VDDIO0

CYDEV_VDDIO0_MV

CYDEV_VDDIO1

CYDEV_VDDIO1_MV

CYDEV_VDDIO2

CYDEV_VDDIO2_MV

CYDEV_VDDIO3

CYDEV_VDDIO3_MV
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Standard Types and Defines

CYDEV_VIO0

CYDEV_VIO0_MV

CYDEV_VIO1

CYDEV_VIO1_MV

CYDEV_VIO2

CYDEV_VIO2_MV

CYDEV_VIO3

CYDEV_VIO3_MV
System Clock Frequency
The following are defines for system clock frequency (from Clock DWR):
PSoC 3 and PSoC 5

BCLK__BUS_CLK__HZ

BCLK__BUS_CLK__KHZ

BCLK__BUS_CLK__MHZ
PSoC 4

CYDEV_BCLK__HFCLK__HZ

CYDEV_BCLK__HFCLK__KHZ

CYDEV_BCLK__HFCLK__MHZ

CYDEV_BCLK__SYSCLK__HZ

CYDEV_BCLK__SYSCLK__KHZ

CYDEV_BCLK__SYSCLK__MHZ
JTAG/Silicon ID
The following is the define for JTAG/Silicon ID for the current device:

CYDEV_CHIP_JTAG_ID
IP Block Information
PSoC Creator generates the following macros in the cyfitter.h file for the IP blocks that exist on the
current device:
#define CYIPBLOCK_<BLOCK NAME>_VERSION <version>
For example:
#define CYIPBLOCK_P3_TIMER_VERSION 0
#define CYIPBLOCK_P3_USB_VERSION 0
#define CYIPBLOCK_P3_VIDAC_VERSION 0
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3
Clocking
PSoC Creator Clocking Implementation
PSoC devices supported by PSoC Creator have flexible clocking capabilities. These clocking capabilities
are controlled in PSoC Creator by selections within the Design-Wide Resources settings, connectivity of
clocking signals on the design schematic, and API calls that can modify the clocking at runtime.
This section describes how PSoC Creator maps clocks onto the device and provides guidance on
clocking methodologies that are optimized for the PSoC architecture.
PSoC 3/PSoC 5LP devices have different clocking architectures than PSoC 4 devices. The System Clock
consolidates Bus Clock (BUS_CLK) on PSoC 3/PSoC 5LP devices and System Clock (SYSCLK) on
PSoC 4 devices. The Master Clock consolidates Master Clock (MASTER_CLK) on PSoC 3/PSoC 5LP
devices and High-Frequency Clock (HFCLK) on PSoC 4 devices.
PSoC 3/PSoC 5LP
Overview
The clock system includes these clock resources:

Four internal clock sources increase system integration:

3 to 48 MHz Internal Main Oscillator (IMO) ±1% at 3 MHz

1 kHz, 33 kHz, 100 kHz Internal Low Speed Oscillator (ILO) outputs

USB Clock Domain, sourced from IMO, MHz External Crystal Oscillator (MHzECO), and
Digital System Interconnect (DSI)

24 to 67 MHz fractional Phase-Locked Loop (PLL) sourced from IMO, MHzECO, and DSI
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13
Clocking

Clock generated using a DSI signal from an external I/O pin or other logic

Two external clock sources provide high precision clocks:

4 to 25 MHzECO

32.768 kHz External Crystal Oscillator (kHzECO) for Real Time Clock (RTC)

Dedicated 16-bit divider for bus clock

Eight individually sourced 16-bit clock dividers for the digital system peripherals

Four individually sourced 16-bit clock dividers with skew for the analog system peripherals

IMO has a USB mode that synchronizes to USB host traffic, requiring no external crystal for USB.
(USB equipped parts only)
PSoC 4
Overview
The clock system includes these clock resources:


Two internal clock sources increase system integration:

PSoC 4000: 24, 32 and 48 MHz IMO ±2% across all frequencies when Vddd is above or
equal to 2.0 V and +/-4% below 2.0 V.

PSoC 4100 and PSoC 4200: 3 to 48 MHz IMO ±2% across all frequencies

32 kHz ILO outputs
External Clock (EXTCLK) generated using a signal from a single designated I/O pin:

The allowable external clock frequency has the same limits as the system clock
frequency.

The device always starts up using the IMO and the external clock must be enabled, so
the device cannot be started from a reset clocked by the external clock.

HFCLK selected from IMO or external clock:

PSoC 4000: The HFCLK frequency cannot exceed 16 MHz.

PSoC 4100 and PSoC 4200: The HFCLK frequency cannot exceed 48 MHz.

Low-Frequency Clock (LFCLK) sourced by ILO

Dedicated prescaler for SYSCLK sourced by HFCLK. The SYSCLK must be equal to or faster
than all other clocks in the device.

PSoC 4000: The SYSCLK frequency cannot exceed 16 MHz.

PSoC 4100 and PSoC 4200: The SYSCLK frequency cannot exceed 48 MHz.

Four peripheral clock dividers, each containing three chainable 16-bit dividers

16 digital and analog peripheral clocks
Power Modes
The IMO is available in Active and Sleep modes. It is automatically disabled/enabled for the proper Deep
Sleep and Hibernate mode entry/exit. The IMO is disabled during Deep Sleep and Hibernate modes.
The EXTCLK is available in Active and Sleep modes. The system will enter/exit Deep Sleep and
Hibernate using external clock. The device will re-enable the IMO if it was enabled before entering Deep
Sleep or Hibernate, but it does not wait for the IMO before starting the CPU. After entering Active mode,
the IMO may take an additional 2 us to begin toggling. The IMO will startup cleanly without glitches, but
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Clocking
any dependency should account for this extra startup time. If desired, firmware may increase wakeup
hold-off using CySysPmSetWakeupHoldoff() function to include this 2 us and ensure the IMO is toggling
by the time Active mode is reached.
The ILO is available in all modes except Hibernate and Stop.
Clock Connectivity
The PSoC architecture includes flexible clock generation logic. Refer to the Technical Reference Manual
for a detailed description of all the clocking sources available in a particular device. The usage of these
various clocking sources can be categorized by how those clocks are connected to elements of a design.
System Clock
This is a special clock. It is closely related to Master Clock. For most designs, Master Clock and System
Clock will be the same frequency and considered to be the same clock. These must be the highest speed
clocks in the system. The CPU will be running off of System Clock and all the peripherals will
communicate to the CPU and DMA using System Clock. When a clock is synchronized, it is synchronized
to Master Clock. When a pin is synchronized it is synchronized to System Clock.
Global Clock
This is a clock that is placed on one of the global low skew digital clock lines. This also includes System
Clock. When a clock is created using a Clock component, it will be created as a global clock. This clock
must be directly connected to a clock input or may be inverted before connection to a clock input. Global
clock lines connect only to the clock input of the digital elements in PSoC. If a global clock line is
connected to something other than a clock input (that is, combinatorial logic or a pin), then the signal is
not sent using low skew clock lines.
Routed Clock
Any clock that is not a global clock is a routed clock. This includes clocks generated by logic (with the
exception of a single inverter) and clocks that come in from a pin.
Clock Synchronization
Each clock in a PSoC device is either synchronous or asynchronous. This is in reference to System Clock
and Master Clock. PSoC is designed to operate as a synchronous system. This was done to enable
communication between the programmable logic and either the CPU or DMA. If these are not
synchronous to a common clock, then any communication requires clocking crossing circuitry. Generally,
asynchronous clocking is not supported except for PLD logic that does not interact with the CPU system.
Synchronous Clock (PSoC 3/ PSoC 5LP)
Examples of synchronous clocks include:

Global clock with sync to Master Clock option set. This option is set by default on the Advanced
tab of the Clock component Configure dialog.

Clock from an input pin with the "Input Synchronized" option selected. This option is set by default
on the Input tab of the Pins component Configure dialog.

Clock derived combinatorially from signals that were all generated from registers that are clocked
by synchronous clocks.
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Clocking
Asynchronous Clock (PSoC 3/ PSoC 5LP)
An asynchronous clock is any clock that is not synchronous. Some examples are:

Any signal coming in from the Digital System Interconnect (DSI) other than a synchronized pin.
These signals must be considered asynchronous because their timing is not guaranteed. This
includes:

What would normally be a global clock (if connected directly to a clock input) that is fed
through logic before being used as a clock

Fixed function block outputs (that is, Counter, Timer, PWM)

Digital signals from the analog blocks

Global clock without the sync option set

Clock from an input pin with Input Synchronized not selected

Clock that is combinatorially created using any asynchronous signal
Making Signals Synchronous (PSoC 3/ PSoC 5LP)
Depending on the source of the clock signal, it can be made synchronous using different methods:

An asynchronous global clock can be made synchronous by checking the Sync with
MASTER_CLK option in the Clock component Configure dialog (this is the default selection).

A routed clock coming from a pin can be made synchronous by checking the Input
Synchronized option in the Pins component Configure dialog (this is the default selection, under
the Pins tab).

Any signal can be made synchronous by using the Sync component and a synchronous clock as
the clock signal.
When synchronizing a signal:

The synchronizing clock must be at least 2x the frequency of the signal being synchronized. If this
rule is violated, then incoming clock edges can be missed and therefore not reflected in the
resulting synchronized clock.

The clock signal output will have all its transitions on the rising edge of the synchronizing clock.

The clock signal output will have its edges moved from their original timing.

The clock signal output will have variation in the high and low pulse widths unless the incoming
clock and the synchronizing clock are directly related to each other.
The following example shows two clocks that have been synchronized to System Clock. Clock_1 has
exactly 2x the period of System Clock. Clock_2 has a period of approximately 3x the period of System
Clock. That results in the high and low pulse widths varying between 1 and 2 System Clock periods. In
both cases all transitions occur at the rising edge of System Clock.
System Clock
Clock_1
Clock_2
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Clocking
Routed Clock Implementation
The clocking implementation in PSoC directly connects global clock signals to the clock input of clocked
digital logic. This applies to both synchronous and asynchronous clocks. Since global clocks are
distributed on low skew clock lines, all clocked elements connected to the same global clock will be
clocked at the same time.
Routed clocks are distributed using the general digital routing fabric. This results in the clock arriving at
each destination at different times. If that clock signal was used directly as the clock, then it would force
the clock to be considered an asynchronous clock. This is because it cannot be guaranteed to transition
at the rising edge of System Clock. This can also result in circuit failures if the output of a register clocked
by an early arriving clock is used by a register clocked by a late arriving version of the same clock.
Under some circumstances, PSoC Creator can transform a routed clock circuit into a circuit that uses a
global clock. If all the sources of a routed clock can be traced back to the output of registers that are
clocked by common global clocks, then the circuit is transformed automatically by PSoC Creator. The
cases where this is possible are:

All signals are derived from the same global clock. This global clock can be asynchronous or
synchronous.

All signals are derived from more than one synchronous global clock. In this case, the common
global clock is System Clock.
The clocking implementation in PSoC includes a built-in edge detection circuit that is used in this
transformation. This does not use PLD resources to implement. The following shows the logical
implementation and the resulting clock timing diagram.
RoutedClk
(Enable)
Latch
(Transparent
when Low)
Clk
GlobalClk
(Effective
Clock)
GlobalClk
RoutedClk
Clk
This diagram shows that the resulting clock occurs synchronous to the global clock on the first clock after
a rising edge of the routed clock.
When analyzing the design to determine the source of a routed clock, another routed clock that was
transformed may be encountered. In that case, the global clock used in that transformation is considered
the source clock for that signal.
The clock transformation used for every routed clock is reported in the report file. This file is located in the
Workspace Explorer under the Results tab after a successful build. The details are shown under the
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Clocking
"Initial Mapping" heading. Each routed clock will be shown with the "Effective Clock" and the "Enable
Signal". The "Effective Clock" is the global clock that is used and the "Enable Signal" is the routed clock
that is edge detected and used as the enable for that clock.
Example with a Divided Clock
A simple divided clock circuit can be used to observe how this transformation is done. The following circuit
clocks the first flip-flop (cydff_1) with a global clock. This generates a clock that is divided by 2 in
frequency. That signal is used as a routed clock that clocks the next flip-flop (cydff_2).
The report file indicates that one global clock has been used and that the single routed clock has been
transformed using the global clock as the effective clock.
The resulting signals generated by this circuit are as follows.
Clock_1
Div2
Div4
It may appear that the Div4 signal is generated by the falling edge of the Div2 signal. This is not the case.
The Div4 signal is generated on the first Clock_1 rising edge following a rising edge on Div2.
Example with a Clock from a Pin
In the following circuit, a clock is brought in on a pin with synchronization turned on. Since
synchronization of pins is done with System Clock, the transformed circuit uses System Clock as the
Effective Clock and uses the rising edge of the pin as the Enable Signal.
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Clocking
If input synchronization was not enabled at the pin, there would not be a global clock to use to transform
the routed clock, and the routed clock would be used directly.
Example with Multiple Clock Sources
In this example, the routed clock is derived from flip-flops that are clocked by two different clocks. Both of
these clocks are synchronous, so System Clock is the common global clock that becomes the Effective
Clock.
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If either of these clocks had been asynchronous, then the routed clock would have been used directly.
Overriding Routed Clock Transformations
The automatic transformation that PSoC Creator performs on routed clocks is generally the
implementation that should be used. There is however a method to force the routed clock to be used
directly. The UDBClkEn component configured in Async mode will force the clock used to be the routed
clock, as shown in the following circuit.
Using Asynchronous Clocks
Asynchronous clocks can be used with PLD logic. However, they are not automatically supported by
control registers, status registers and datapath elements because of the interaction with the CPU those
elements have. Most Cypress library components will only work with synchronous clocks. They
specifically force the insertion of a synchronizer automatically if the clock provided is asynchronous.
Components that are designed to work with asynchronous clocks such as the SPI Slave will specifically
describe how they handle clocking in their datasheet.
If an asynchronous clock is connected directly to something other than PLD logic, then a Design Rule
Check (DRC) error is generated. For example, if an asynchronous pin is connected to a control register
clock, a DRC error is generated.
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As stated in the error message, the error can be removed by using a UDBClkEn component in async
mode. That won’t remove the underlying synchronization issue, but it will allow the design to override the
error if the design has handled synchronization in some other way.
Clock Crossing
Multiple clock domains are commonly needed in a design. Often these multiple domains do not interact
and therefore clocking crossings do not occur. In the case where signals generated in one clock domain
need to be used in another clock domain, special care must be taken. There is the case where the two
clock domains are asynchronous from each other and the case where both clock domains are
synchronous to System Clock.
When both clocks are synchronous to System Clock, signals from the slower clock domain can be freely
used in the other clock domain. In the other direction, care must be taken that the signals from the faster
clock domain are active for a long enough period that they will be sampled by the slower clock domain. In
both directions the timing constraints that must be met are based on the speed of System Clock not the
speed of either of the clock domains.
The only guarantee between the clock domains is that their edges will always occur on a rising edge of
System Clock. That means that the rising edges of the two clock domains can be as close as a single
System Clock cycle apart. This is true even when the clock domains are multiples of each other, since
their clock dividers are not necessarily aligned. If combinatorial logic exists between the two clock
domains, a flip-flop may need to be inserted to keep from limiting the frequency of System Clock
operation. By inserting the flip-flop, the crossing from one clock domain to the other is a direct flip-flop to
flip-flop path.
When the clock domains are unrelated to each other, a synchronizer must be used between the clock
domains. The Sync component can be used to implement the synchronization function. It should be
clocked by the destination clock domain.
The Sync component is implemented using a special mode of the status register that implements a
double synchronizer. The input signal must have a pulse width of at least the period of the sampling clock.
The exact delay to go through the synchronizer will vary depending on the alignment of the incoming
signal to the synchronizing clock. This can vary from just over one clock period to just over two clock
periods. If multiple signals are being synchronized, the time difference between two signals entering the
synchronizer and those same two signals at the output can change by as much as one clock period,
depending on when each is successfully sampled by the synchronizer.
Gated Clocks
Global clocks should not be used for anything other than directly clocking a circuit. If a global clock is
used for logic functionality, the signal is routed using an entirely different path without guaranteed timing.
A circuit such as the following should be avoided since timing analysis cannot be performed.
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This circuit is implemented with a routed clock, has no timing analysis support, and is prone to the
generation of glitches on the clock signal when the clock is enabled and disabled.
The following circuit implements the equivalent function and is supported by timing analysis, only uses
global clocks, and has no reliability issues. This circuit does not gate the clock, but instead logically
enables the clocking of new data or maintains the current data.
If access to a clock is needed, for example to generate a clock to send to a pin, then a 2x clock should be
used to clock a toggle flip-flop. The output of that flip-flop can then be used with the associated timing
analysis available.
Fixed-Function Clocking
On the schematic, the clock signals sent to fixed-function peripherals and to UDB-based peripherals
appear to be the same clock. However, the timing relationship between the clock signals as they arrive at
these different peripheral types is not guaranteed. Additionally the routing delay for the data signals is not
guaranteed. Therefore when fixed-function peripherals are connected to signals in the UDB array, the
signals must be synchronized as shown in the following example. No timing assumptions should be made
about signals coming from fixed-function peripherals.
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Changing Clocks in Run-time
Impact on Components Operation
The components with internal clocks are directly impacted by the change of the system clock frequencies
or sources. The components clock frequencies obtained using design-time dividers. The run-time change
of components clock source will correspondingly change the internal component clock. Refer to the
component datasheet for the details.
CyDelay APIs
The CyDelay APIs implement simple software-based delay loops. The loops compensate for system clock
frequency. The CyDelayFreq() function must be called in order to adjust CyDelay(), CyDelayUs() and
CyDelayCycles() functions to the new system clock value.
Cache Configuration
If the CPU clock frequency increases during device operation, the number of clock cycles cache will wait
before sampling data coming back from Flash should be adjusted. If the CPU clock frequency decreases,
the number of clock cycles can be also adjusted to improve CPU performance. See
"CyFlash_SetWaitCycles()" for PSoC 3/PSoC 5LP and “CySysFlashSetWaitCycles()” for PSoC 4 for more
information.
Low Voltage Analog Boost Clocks (PSoC 3/PSoC 5LP)
When the operating voltage (Vdda) of a PSoC 3/PSoC 5LP device is below 2.7 V, analog positive pumps
of the SC-blocks require a boost clock input in order to keep performance within specification. Between
2.7 V and 4.0 V, the boost is optional and may improve performance. Above 4.0 V, the boost must not be
used.
In previous releases of PSoC Creator, an analog clock resource was silently reserved for every
component instance of the requiring the boost (TIA, Mixer, PGA, and PGA_Inv). This means that analog
designs would prematurely exhaust available resources when Vdda was low. This feature is implemented
to automatically share the design-wide analog clock resource and provide the ability to control analog
pumps and boost clock for all utilized SC-blocks during run-time using the CySetScPumps() function.
Components that are implemented in SC-blocks (TIA, Mixer, PGA, and PGA_Inv) will be initialized based
on Vdda and Variable Vdda design-time options. The CySetScPumps() function can be used to
enable/disable positive pumps and boost clock at run-time if operating voltage (Vdda) drops below the
2.7 V level. It is the user's responsibility to monitor the Vdda level.
When the operating voltage (Vdda) of a PSoC 3/PSoC 5LP device drops below 4.0 V, the analog pumps
for the analog routing switches must be enabled by calling the SetAnalogRoutingPumps() function with
the corresponding parameter. When Vdda rises above 4.0 V, the analog pumps for the analog routing
switches must be disabled. It is the user's responsibility to monitor the Vdda level at run-time. The analog
pumps for the analog routing switches are configured on device startup based on the Vdda and Variable
Vdda design-time options.
A “Variable Vdda” option in the System tab of the PSoC Creator Design-Wide Resources (DWR) file is
added to allow the creation of a design-wide analog clock resource (ScBoostClk) that will be used as a
boost clock source for analog blocks. This clock is created with a desired frequency of 10 MHz. The
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Clocking
constraint is that one of the system clock sources (MASTER_CLK, PLL_OUT, XTAL, etc) should have a
value which can produce a 10-12 MHz frequency via an integer divide. In order to ensure that sufficient
current is provided to the SC-block by the pump, this value cannot be changed.
The dependency between Vdda and Variable Vdda values configured in the System tab of the PSoC
Creator Design-Wide Resources (DWR) file is explained in the following table.
Vdda
< 2.7 V
≥ 2.7 V
≥ 2.7 V
Variable Vdda
Always Enabled
Enabled
Disabled
ScBoostClk clock created
Yes
Yes
No
ScBoostClk started on reset
Yes
No
No
Note The previous versions SC-block components (TIA, Mixer, PGA and, and PGA_Inv) will continue to
use a dedicated local clock and the new Low Voltage Analog Boost Clocks APIs will not affect those
clocks.
APIs
There is one set of APIs used for PSoC 3 and PSoC 5LP devices, and a different set of APIs used for
PSoC 4 devices. Functions starting with CySysClk are applicable to PSoC 4 only. All other functions are
applicable to PSoC 3and PSoC 5LP only.
PSoC 3/PSoC 5LP APIs
uint8 CyPLL_OUT_Start(uint8 wait)
Description: Enables the PLL. Optionally waits for it to become stable. Waits at least 250 us or
until it is detected that the PLL is stable.
Parameters: wait:
•
•
Return Value: Status
•
•
0: Return immediately after configuration
1: Wait for PLL lock or timeout
CYRET_SUCCESS - Completed successfully
CYRET_TIMEOUT - Timeout occurred without detecting a stable clock. If
the input source of the clock is jittery, then the lock indication may not
occur. However, after the timeout has expired the generated PLL clock
can still be used.
Side Effects and If wait is enabled, this function uses the Fast Time Wheel (FTW) to time the wait.
Restrictions: Any other use of the FTW will be stopped during the period of this function and
then restored.
This function uses the 100 KHz ILO. If the 100 KHz ILO is not enabled, this
function will enable it for the duration of this function execution.
No changes to the setup of the ILO, FTW, Central Time Wheel (CTW) or Once
Per Second interrupt may be made by interrupt routines for the duration of this
function execution. The current operation of the ILO, CTW and Once Per Second
interrupt are maintained during the operation of this function, provided the reading
of the Power Manager Interrupt Status Register is only done using the
CyPmReadStatus() function.
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void CyPLL_OUT_Stop()
Description: Disables the PLL.
Parameters: None
Return Value: None
void CyPLL_OUT_SetPQ(uint8 pDiv, uint8 qDiv, uint8 current)
Description: Sets the P and Q dividers and the charge pump current. The Frequency Out will
be P/Q * Frequency In. The PLL must be disabled before calling this function.
Parameters: P: Valid range [8 - 255]
Q: Valid range [1 - 16]. Input Frequency / Q must be in the range of 1 MHz to
3 MHz.
current: Valid range [1 - 7]. Charge pump current in uA. Refer to the device TRM
and datasheet for more information.
Return Value: None
Side Effects and If the CPU clock frequency increases during device operation, call
Restrictions: CyFlash_SetWaitCycles() with the appropriate parameter to adjust the number of
clock cycles cache will wait before sampling data coming back from Flash. If the
CPU clock frequency decreases, you can call CyFlash_SetWaitCycles() to
improve CPU performance. See "CyFlash_SetWaitCycles()" for more information.
void CyPLL_OUT_SetSource(uint8 source)
Description: Sets the input clock source to the PLL. The PLL must be disabled before calling
this function.
Parameters: source: One of the three available PLL clock sources
Define
Source
CY_PLL_SOURCE_IMO
CY_PLL_SOURCE_XTAL
CY_PLL_SOURCE_DSI
IMO
MHz Crystal
DSI
Return Value: None
Side Effects and If the CPU clock frequency increases during device operation, call
Restrictions: CyFlash_SetWaitCycles() with the appropriate parameter to adjust the number of
clock cycles cache will wait before sampling data coming back from Flash. If the
CPU clock frequency decreases, you can call CyFlash_SetWaitCycles() to
improve CPU performance. See "CyFlash_SetWaitCycles()" for more information.
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void CyIMO_Start(uint8 wait)
Description: Enables the IMO. Optionally waits at least 6us for it to settle.
Parameters: wait:
•
•
0: Return immediately after configuration
1: Wait for at least 6us for the IMO to settle
Return Value: None
Side Effects and If wait is enabled, this function uses the FTW to time the wait. Any other use of
Restrictions: the FTW will be stopped during the period of this function and then restored.
This function uses the 100 KHz ILO. If the 100 KHz ILO is not enabled, this
function will enable it for the duration of this function execution.
No changes to the setup of the ILO, FTW, CTW, or Once Per Second interrupt
may be made by interrupt routines for the duration of this function execution. The
current operation of the ILO, CTW, and Once Per Second interrupt are
maintained during the operation of this function, provided the reading of the
Power Manager Interrupt Status Register is only done using the
CyPmReadStatus() function.
void CyIMO_Stop()
Description: Disables the IMO.
Parameters: None
Return Value: None
void CyIMO_SetFreq(uint8 freq)
Description: Sets the frequency of the IMO. Changes may be made while the IMO is running.
Parameters: freq: Frequency of IMO operation
Return Value:
Define
Frequency
CY_IMO_FREQ_3MHZ
CY_IMO_FREQ_6MHZ
CY_IMO_FREQ_12MHZ
CY_IMO_FREQ_24MHZ
CY_IMO_FREQ_48MHZ
CY_IMO_FREQ_62MHZ
CY_IMO_FREQ_74MHZ
CY_IMO_FREQ_USB
3 MHz
6 MHz
12 MHz
24 MHz
48 MHz
62.6 MHz
74.7 MHz
24 MHz (Trimmed for USB operation)
None
Side Effects and If the CPU clock frequency increases during device operation, call
Restrictions: CyFlash_SetWaitCycles() with the appropriate parameter to adjust the number of
clock cycles cache will wait before sampling data coming back from Flash. If the
CPU clock frequency decreases, you can call CyFlash_SetWaitCycles() to
improve CPU performance. See "CyFlash_SetWaitCycles()" for more information.
When the USB setting is chosen, the USB clock locking circuit is enabled.
Otherwise this circuit is disabled. The USB block must be powered before
selecting the USB setting.
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void CyIMO_SetSource(uint8 source)
Description: Sets the source of the clock output from the IMO block. The output from the IMO
is by default the IMO itself. Optionally the MHz Crystal or a DSI input can be the
source of the IMO output instead.
Parameters: source: One of the three available IMO output sources
Define
Source
CY_IMO_SOURCE_IMO
CY_IMO_SOURCE_XTAL
CY_IMO_SOURCE_DSI
IMO
MHz Crystal
DSI
Return Value: None
Side Effects and If the CPU clock frequency increases during device operation, call
Restrictions: CyFlash_SetWaitCycles() with the appropriate parameter to adjust the number of
clock cycles cache will wait before sampling data coming back from Flash. If the
CPU clock frequency decreases, you can call CyFlash_SetWaitCycles() to
improve CPU performance. See "CyFlash_SetWaitCycles()" for more information.
void CyIMO_EnableDoubler()
Description: Enables the IMO doubler. The 2x frequency clock is used to convert a 24 MHz
input to a 48 MHz output for use by the USB block.
Parameters: None
Return Value: None
void CyIMO_DisableDoubler()
Description: Disables the IMO doubler.
Parameters: None
Return Value: None
void CyBusClk_SetDivider(uint16 divider)
Description: Sets the divider value used to generate Bus Clock.
Parameters: divider: Valid range [0-65535]. The clock will be divided by this value + 1. For
example to divide by 2 this parameter should be set to 1.
Return Value: None
Side Effects and If the CPU clock frequency increases during device operation, call
Restrictions: CyFlash_SetWaitCycles() with the appropriate parameter to adjust the number of
clock cycles cache will wait before sampling data coming back from Flash. If the
CPU clock frequency decreases, you can call CyFlash_SetWaitCycles() to
improve CPU performance. See "CyFlash_SetWaitCycles()" for more information.
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void CyCpuClk_SetDivider(uint8 divider)
Description: Sets the divider value used to generate the CPU Clock. Applies to PSoC 3 only.
Parameters: divider: Valid range [0-15]. The clock will be divided by this value + 1. For
example to divide by 2 this parameter should be set to 1.
Return Value: None
Side Effects and If the CPU clock frequency increases during device operation, call
Restrictions: CyFlash_SetWaitCycles() with the appropriate parameter to adjust the number of
clock cycles cache will wait before sampling data coming back from Flash. If the
CPU clock frequency decreases, you can call CyFlash_SetWaitCycles() to
improve CPU performance. See "CyFlash_SetWaitCycles()" for more information.
void CyMasterClk_SetSource(uint8 source)
Description: Sets the source of the master clock.
Parameters: source: One of the four available Master clock sources
Define
Source
CY_MASTER_SOURCE_IMO
CY_MASTER_SOURCE_PLL
CY_MASTER_SOURCE_XTAL
CY_MASTER_SOURCE_DSI
IMO
PLL
MHz Crystal
DSI
Return Value: None
Side Effects and The current source and the new source must both be running and stable before
Restrictions: calling this function.
If the CPU clock frequency increases during device operation, call
CyFlash_SetWaitCycles() with the appropriate parameter to adjust the number of
clock cycles cache will wait before sampling data coming back from Flash. If the
CPU clock frequency decreases, you can call CyFlash_SetWaitCycles() to
improve CPU performance. See "CyFlash_SetWaitCycles()" for more information.
void CyMasterClk_SetDivider(uint8 divider)
Description: Sets the divider value used to generate Master Clock.
Parameters: divider: Valid range [0-255]. The clock will be divided by this value + 1. For
example to divide by 2 this parameter should be set to 1.
Return Value: None
Side Effects and When changing the Master or Bus Clock divider value from div-by-n to div-by-1,
Restrictions: the first clock cycle output after the div-by-1 can be up to 4 ns shorter than the
final/expected div-by-1 period.
If the CPU clock frequency increases during device operation, call
CyFlash_SetWaitCycles() with the appropriate parameter to adjust the number of
clock cycles cache will wait before sampling data coming back from Flash. If the
CPU clock frequency decreases, you can call CyFlash_SetWaitCycles() to
improve CPU performance. See "CyFlash_SetWaitCycles()" for more information.
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void CyUsbClk_SetSource(uint8 source)
Description: Sets the source of the USB clock.
Parameters: source: One of the four available USB clock sources
Define
Source
CY_USB_SOURCE_IMO2X
CY_USB_SOURCE_IMO
CY_USB_SOURCE_PLL
CY_USB_SOURCE_DSI
IMO 2x
IMO
PLL
DSI
Return Value: None
void CyILO_Start1K()
Description: Enables the ILO 1 KHz oscillator.
Note The ILO 1 KHz oscillator is always enabled by default, regardless of the
selection in the Clock Editor. Therefore, this API is only needed if the oscillator
was turned off manually.
Parameters: None
Return Value: None
void CyILO_Stop1K()
Description: Disables the ILO 1 KHz oscillator.
Note The ILO 1 KHz oscillator must be enabled if Sleep or Hibernate low power
mode APIs are expected to be used. For more information, refer to the Power
Management section of this document.
Parameters: None
Return Value: None
void CyILO_Start100K()
Description: Enables the ILO 100 KHz oscillator.
Parameters: None
Return Value: None
void CyILO_Stop100K()
Description: Disables the ILO 100 KHz oscillator.
Parameters: None
Return Value: None
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void CyILO_Enable33K()
Description: Enables the ILO 33 KHz divider.
Note The 33 KHz clock is generated from the 100 KHz oscillator, so it must also
be running in order to generate the 33 KHz output.
Parameters: None
Return Value: None
void CyILO_Disable33K()
Description: Disables the ILO 33 KHz divider.
Note that the 33 KHz clock is generated from the 100 KHz oscillator, but this API
does not disable the 100 KHz clock.
Parameters: None
Return Value: None
void CyILO_SetSource(uint8 source)
Description: Sets the source of the clock output from the ILO block.
Parameters: source: One of the three available ILO output sources
Define
Source
CY_ILO_SOURCE_100K
CY_ILO_SOURCE_33K
CY_ILO_SOURCE_1K
ILO 100 KHz
ILO 33 KHz
ILO 1 KHz
Return Value: None
uint8 CyILO_SetPowerMode(uint8 mode)
Description: Sets the power mode used by the ILO during power down. Allows for lower power
down power usage resulting in a slower startup time.
Parameters: mode:
Define
Description
CY_ILO_FAST_START
Faster start-up, internal bias left on when
powered down.
Slower start-up, internal bias off when
powered down.
CY_ILO_SLOW_START
Return Value: Previous power mode
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uint8 CyXTAL_Start(uint8 wait)
Description: Enables the MHz crystal.
Waits until the XERR bit is low (no error) for a millisecond or until the number of
milliseconds specified by the wait parameter has expired.
Parameters: wait: Valid range [0-255]. This is the timeout value in milliseconds. The
appropriate value is crystal specific.
Return Value: Status
CYRET_SUCCESS - Completed successfully
CYRET_TIMEOUT - Timeout occurred without detecting a low value on XERR.
Side Effects and If wait is enabled (non-zero wait), this function uses the FTW to time the wait. Any
Restrictions: other use of the FTW will be stopped during the period of this function and then
restored.
This function also uses the 100 KHz ILO. If the 100 KHz is not enabled, this
function will enable it for the duration of this function execution.
No changes to the setup of the ILO, FTW, CTW, or Once Per Second interrupt
may be made by interrupt routines for the duration of this function execution. The
current operation of the ILO, CTW, and Once Per Second interrupt are
maintained during the operation of this function provided the reading of the Power
Manager Interrupt Status Register is only done using the CyPmReadStatus()
function.
void CyXTAL_Stop()
Description: Disables the megahertz crystal oscillator.
Parameters: None
Return Value: None
void CyXTAL_EnableErrStatus()
Description: Enables the generation of the XERR status bit for the megahertz crystal.
Parameters: None
Return Value: None
void CyXTAL_DisableErrStatus()
Description: Disables the generation of the XERR status bit for the megahertz crystal.
Parameters: None
Return Value: None
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uint8 CyXTAL_ReadStatus()
Description: Reads the XERR status bit for the megahertz crystal. This status bit is a sticky
clear on read value.
Parameters: None
Return Value: Status: 0: No error, 1: Error
void CyXTAL_EnableFaultRecovery()
Description: Enables the fault recovery circuit which will switch to the IMO in the case of a fault
in the megahertz crystal circuit. The crystal must be up and running with the
XERR bit at 0, before calling this function to prevent immediate fault switchover.
Parameters: None
Return Value: None
void CyXTAL_DisableFaultRecovery()
Description: Disables the fault recovery circuit which will switch to the IMO in the case of a
fault in the megahertz crystal circuit.
Parameters: None
Return Value: None
void CyXTAL_SetStartup(uint8 setting)
Description: Sets the startup settings for the crystal.
Parameters: setting: Valid range [0-31]. Value is dependent on the frequency and quality of the
crystal being used. Refer to the device TRM and datasheet for more information.
Return Value: None
void CyXTAL_SetFbVoltage(uint8 setting)
Description: Sets the feedback reference voltage to use for the crystal circuit.
Parameters: setting: Valid range [0-15]. Refer to the device TRM and datasheet for more
information.
Return Value: None
Side Effects and The feedback reference voltage must be greater than the watchdog reference
Restrictions: voltage.
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void CyXTAL_SetWdVoltage(uint8 setting)
Description: Sets the reference voltage used by the watchdog to detect a failure in the crystal
circuit.
Parameters: setting: Valid range [0-7]. Refer to the device TRM and datasheet for more
information.
Return Value: None
Side Effects and The feedback reference voltage must be greater than the watchdog reference
Restrictions: voltage.
void CyXTAL_32KHZ_Start()
Description: Enables the 32 KHz Crystal Oscillator.
Parameters: None
Return Value: None
void CyXTAL_32KHZ_Stop()
Description: Disables the 32 KHz Crystal Oscillator.
Parameters: None
Return Value: None
uint8 CyXTAL_32KHZ_ReadStatus()
Description: Reads the two status bits for the 32 KHz oscillator.
Parameters: None
Return Value: Status
Define
Source
CY_XTAL32K_ANA_STAT
Analog measurement
1: Stable
0: Not stable
uint8 CyXTAL_32KHZ_SetPowerMode(uint8 mode)
Description: Sets the power mode for the 32 KHz oscillator used during sleep mode. Allows for
lower power during sleep when there are fewer sources of noise. During active
mode the oscillator is always run in high power mode.
Parameters: mode:
•
•
0: High power mode
1: Low power mode during sleep
Return Value: Previous power mode
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33
Clocking
void CySetScPumps(uint8 enable)
Description: Starts/stops analog boost clock and configures SC-blocks positive pumps.
Parameters: enable:
•
•
1: Starts analog boost clock and enables positive pumps.
0: Disables positive pumps for enabled SC-blocks and stops analog boost
clock if all SC-blocks are disabled.
Return Value: None
void SetAnalogRoutingPumps(uint8 enabled)
Description: Enables or disables the analog pumps feeding analog routing switches. Intended
to be called at startup, based on the Vdda system configuration; may be called
during operation when the user informs us that the Vdda voltage crossed the
pump threshold.
Parameters: enabled:
•
•
1: Enable the pumps.
0: Disable the pumps.
Return Value: None
PSoC 4 APIs
void CySysClkImoStart(void)
Description: Enables the IMO.
Parameters: None
Return Value: None
Side Effects and None
Restrictions:
void CySysClkImoStop(void)
Description: Disables the IMO.
Parameters: None
Return Value: None
Side Effects and This function will have no effect if WDT is locked (CySysWdtLock() is called). Call
Restrictions: CySysWdtUnlock() to unlock WDT and be able to stop ILO. Note that ILO is
required for WDT's operation.
void CySysClkIloStart(void)
Description: Starts the ILO.
Parameters: None
Return Value: None
Side Effects and None
Restrictions:
PSoC® Creator™ System Reference Guide, Document Number: 001-94480, Rev. **
34
Clocking
void CySysClkIloStop(void)
Description: Disables the ILO.
Parameters: None
Return Value: None
Side Effects and None
Restrictions:
void CySysClkWriteHfclkDirect (uint32 clkSelect)
Description: Selects the direct source for the HFCLK.
Parameters: clkSelect: One of the available HFCLK direct sources.
Define
Source
CY_SYS_CLK_HFCLK_IMO
CY_SYS_CLK_HFCLK_EXTCLK
IMO
External clock pin
Return Value: None
Side Effects and If the SYSCLK frequency increases during device operation, call
Restrictions: CySysFlashSetWaitCycles() with the appropriate parameter to adjust the number
of clock cycles the cache will wait before sampling data comes back from Flash. If
the SYSCLK frequency decreases, call CySysFlashSetWaitCycles() to improve
CPU performance. See CySysFlashSetWaitCycles() description for more
information.
PSoC 4000: The SYSCLK has a maximum speed of 16 MHz, so HFCLK and
SYSCLK dividers should be selected in a way to not to exceed 16 MHz for the
System clock.
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35
Clocking
void CySysClkWriteSysclkDiv (uint32 divider)
Description: Selects the prescaler divide amount for SYSCLK from HFCLK.
Parameters: divider: Power of 2 prescaler selection.
Define
Divider
CY_SYS_CLK_SYSCLK_DIV1
CY_SYS_CLK_SYSCLK_DIV2
CY_SYS_CLK_SYSCLK_DIV4
CY_SYS_CLK_SYSCLK_DIV8
CY_SYS_CLK_SYSCLK_DIV16
CY_SYS_CLK_SYSCLK_DIV32
CY_SYS_CLK_SYSCLK_DIV64
CY_SYS_CLK_SYSCLK_DIV128
1
2
4
8
16
32
64
128
Note The dividers above CY_SYS_CLK_SYSCLK_DIV8 are not available for the
PSoC 4000 family.
Return Value: None
Side Effects and If the SYSCLK frequency increases during device operation, call
Restrictions: CySysFlashSetWaitCycles() with the appropriate parameter to adjust the number
of clock cycles the cache will wait before sampling data comes back from Flash. If
the SYSCLK clock frequency decreases, call CySysFlashSetWaitCycles() to
improve CPU performance. See CySysFlashSetWaitCycles() description for more
information.
PSoC 4000: The SYSCLK has a maximum speed of 16 MHz, so HFCLK and
SYSCLK dividers should be selected in a way to not to exceed 16 MHz for the
System clock.
void CySysClkWriteImoFreq (uint32 freq)
Description: Sets the frequency of the IMO.
Parameters: freq: Frequency for operation of the IMO.
PSoC 4000: Valid values are 24, 32 and 48 MHz.
PSoC 4100 and PSoC 4200: Valid range [3-48] with step size equal to 1 MHz.
Return Value: None
Side Effects and If the SYSCLK frequency increases during device operation, call
Restrictions: CySysFlashSetWaitCycles() with the appropriate parameter to adjust the number
of clock cycles the cache will wait before sampling data comes back from Flash. If
the SYSCLK clock frequency decreases, call CySysFlashSetWaitCycles() to
improve CPU performance. See CySysFlashSetWaitCycles() description for more
information.
PSoC 4000: The SYSCLK has maximum speed of 16 MHz, so HFCLK and
SYSCLK dividers should be selected in a way, to not to exceed 16 MHz for the
System clock.
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4
Power Management
There is a full range of power modes supported by PSoC devices to control power consumption and the
amount of available resources. See the following table for the supported power modes.
Table 1. Power modes
Architecture
PSoC 3 / PSoC 5LP
PSoC 4
Family
All
4000
4100 and 4200
Active











Alternate Active
Sleep
Deep Sleep
Hibernate

Stop
PSoC 3/PSoC 5LP devices support the following power modes (in order of high to low power
consumption): Active, Alternate Active, Sleep, and Hibernate.
PSoC 4 devices support the following power modes (in order of high to low power consumption): Active,
Sleep, Deep Sleep, Hibernate, and Stop. Active, Sleep and Deep-Sleep are standard ARM defined power
modes, supported by the ARM CPUs. Hibernate/Stop are even lower power modes that are entered from
firmware just like Deep-Sleep, but on wakeup the CPU (and all peripherals) goes through a full reset.
For the ARM-based devices (PSoC 4/PSoC 5LP), an interrupt is required for the CPU to wake up. The
Power Management implementation assumes that wakeup time is configured with a separate component
(component-based wakeup time configuration) for an interrupt to be issued on terminal count. For more
information, refer to the "Wakeup Time Configuration" section.
All pending interrupts should be cleared before the device is put into low power mode, even if they are
masked.
PSoC 3/PSoC 5LP Implementation
Low Power Usage
PSoC 5 devices will not go into low power modes while the debugger is running.
For PSoC 3/PSoC 5LP devices, the power manager will not put the device into a low power state if the
system performance controller (SPC) is executing a command. The device will go into low power mode
after the SPC completes command execution. The SPC is used by Flash API, EEPROM and DieTemp
components. Please refer to the corresponding component datasheet for the more information.
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37
Power Management
Clock Configuration
There are a few device configuration requirements for proper low power mode entry and wakeup.

The clock system should be prepared before entering Sleep and Hibernate mode to ensure that it
will switch between Active modes and low power modes as expected.

The CyPmSaveClocks() and CyPmRestoreClocks() functions are responsible for preparing clock
configuration before entering low power mode and after waking up to Active mode, respectively.
In general, CyPmSaveClocks() saves the configuration and sets the requirements for low power
mode entry. CyPmRestoreClocks() restores the clock configuration to its original state.

The IMO is required to be the source for the Master clock. So, the IMO clock value is set
corresponding to the "Enable Fast IMO During Startup" option on the Design-Wide Resources
System Editor. If this option is enabled, the IMO clock frequency is set to 48 MHz; otherwise, is
set to 12 MHz.
Note The IMO clock frequency is always set to 12 MHz on PSoC 5 devices. The PLL and MHz
ECO are turned off when the Master clock is sourced by IMO.
The IMO value must be 12 MHz just before entering Sleep and Hibernate modes. The IMO
frequency is set to 12 MHz by CyPmSleep()/CyPmHibernate() just before entering the specified
low power mode (without correcting the number of wait cycles for the flash). The IMO frequency
is restored immediately on wakeup.

The Bus and Master clock dividers are set to a divide-by-one value and the new value of flash
wait cycles is set to match the new value of the CPU frequency. Refer to the description of the
CyFlash_SetWaitCycles() function for more information.
The 1 KHz ILO must be enabled (it is always enabled by default, regardless of the selection in the Clock
Editor) for all devices for correct operation in Sleep and Hibernate low power modes. It is used to
measure the Hibernate/Sleep regulator settling time after a reset. During this time, the system ignores
requests to enter these modes. The hold-off delay is measured using rising edges of the 1 kHz ILO. The
terminal count is set by the Sleep Regulator Trim Register (PWRSYS_SLP_TR). Caution Do not modify
this register. Refer to the corresponding device Registers TRM for more information.
The 32.768-kHz external crystal oscillator (32kHzECO) provides precision timing with minimal power
consumption using an external 32.768-kHz watch crystal. The oscillator’s power mode during device’s
Sleep mode configured by the CyXTAL_32KHZ_SetPowerMode() function. By default, oscillator runs in
the high power mode.
Calling the CyPmSaveClocks() function will modify device clocking configuration. As a result, any
component that relies on clocking should not be used until calling the CyPmRestoreClocks() function,
which will restore the original clocking configuration. For information on component clocking
requirements, refer to the corresponding component datasheet.
Wakeup Time Configuration
There are three timers that can wake up a device from low power mode: CTW, FTW, and one pulse per
second (One PPS). Refer to the device TRM and datasheet for more information on these timers.
There are two ways of configuring wakeup time:

Parameter-based wakeup time configuration is done by calling the CyPmSleep() and
CyPmAltAct() functions with desired parameters. This configuration method is available only for
the PSoC 3 devices.

Component-based wakeup time configuration. The CTW wakeup interval is configured with the
Sleep Timer component. The one second interval is configured with the RTC component.
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38
Power Management
There is no wakeup time configuration available for the Hibernate mode.
It is important to keep in mind that it is only guaranteed that the first CTW and FTW intervals will be less
than specified. To make subsequent intervals to have nominal values, the corresponding timer is enabled
by the CyPmSleep() and CyPmAltAct() functions, and the timer left enabled. Note that some APIs can
also use this timer. This can cause the timer to always be enabled (the timer interval can be changed only
if the corresponding timer is disabled) before low power mode entry and hence the wakeup interval will
always be less than expected.
The CyPmReadStatus() function must be called just after wakeup with a corresponding parameter (for
example, with CY_PM_CTW_INT if the device is configured to wake up on CTW) to clear interrupt status
bits.
When CTW is used as a wakeup timer, the CyPmReadStatus() function must always be called (when
wakeup is configured in a parameter or component based method) after wakeup to clear the CTW
interrupt status bit. It is required for this function to be called within 1 ms (1 clock cycle of the ILO) after
the CTW event occurred.
Wakeup Source Configuration
You can configure which wakeup source may wake up the device from Alternate Active and Sleep low
power modes. The source is not configured to wake up the device; it just allows doing that. The
component associated with the wakeup source has to be properly configured to act as a wakeup source.
For PSoC 5LP devices, the interrupts associated with wakeup sources must also be enabled to also wake
up the CPU.
PSoC 3 Alternate Active Mode Specific Issues

Any interrupt, whether it is enabled at the interrupt controller or not, will wake the device from
Alternate Active power mode.

The edge detector is also bypassed, so the wakeup source is always level triggered.

Directly connected DMA interrupts will not wake from this mode. They must be routed through the
DSI in order to generate a wakeup condition.
PSoC 5LP Specific Issues
For PSoC 5LP, the wakeup source is available for Sleep mode and is not available for Alternate Active
mode. In the case of Alternate Active mode, the wakeup source argument is ignored and any of the
available sources will wake the device.
For PSoC 5LP, the interrupt component connected to the wakeup source may not use the
"RISING_EDGE" detect option. Use the "LEVEL" option instead.
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Power Management
Power Management APIs
void CyPmSaveClocks()
Description: This function is called in preparation for entering sleep or hibernate low power
modes. Saves all state of the clocking system that doesn’t persist during
sleep/hibernate or that needs to be altered in preparation for sleep/hibernate.
Shuts down all the digital and analog clock dividers for the active power mode
configuration.
Switches the master clock over to the IMO and shuts down the PLL and MHz
Crystal. The IMO frequency is set to either 12 MHz or 48 MHz to match the
Design-Wide Resources System Editor "Enable Fast IMO During Startup" setting.
The ILO and 32 KHz oscillators are not impacted. The current Flash wait state
setting is saved and the Flash wait state setting is set for the current IMO speed.
Note If the Master Clock source is routed through the DSI inputs, then it must be
set manually to another source before using the CyPmSaveClocks() /
CyPmRestoreClocks() functions.
Parameters: None
Return Value: None
Side Effects and All peripheral clocks will be off after this API method call.
Restrictions:
void CyPmRestoreClocks()
Description: Restores any state that was preserved by the last call to CyPmSaveClocks. The
Flash wait state setting is also restored.
Note If the Master Clock source is routed through the DSI inputs, then it must be
set manually to another source before using the CyPmSaveClocks() /
CyPmRestoreClocks() functions.
The merge region could be used to process state when the megahertz crystal is
not ready after the hold-off timeout.
Parameters: None
Return Value: None
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Power Management
void CyPmAltAct(uint16 wakeupTime, uint16 wakeupSource)
Description: Puts the part into the Alternate Active (Standby) state. The Alternate Active state
can allow for any of the capabilities of the device to be active, but the operation of
this function is dependent on the CPU being disabled during the Alternate Active
state. The configuration code and the component APIs will configure the template
for the Alternate Active state to be the same as the Active state with the exception
that the CPU will be disabled during Alternate Active.
Note Before calling this function, you must manually configure the power mode of
the source clocks for the timer that is used as the wakeup timer.
PSoC 3: Before switching to Alternate Active, if a wakeupTime other than NONE
is specified, then the appropriate timer state is configured as specified with the
interrupt for that timer disabled. The wakeup source will be the combination of the
values specified in the wakeupSource and any timer specified in the wakeupTime
argument. Once the wakeup condition is satisfied, then all saved state is restored
and the function returns in the Active state.
Note If the wakeupTime is made with a different value, the period before the
wakeup occurs can be significantly shorter than the specified time. If the next call
is made with the same wakeupTime value, then the wakeup will occur the
specified period after the previous wakeup occurred.
If a wakeupTime other than NONE is specified, then upon exit the state of the
specified timer will be left as specified by wakeupTime with the timer enabled and
the interrupt disabled. If the CTW, FTW or One PPS is already configured for
wakeup, for example with the Sleep Timer or RTC components, then specify
NONE for the wakeupTime and include the appropriate source for wakeupSource.
PSoC 5LP: Neither parameter is used. That means NONE should be passed for
the parameters. The device will go into Alternate Active mode until an enabled
interrupt occurs.
Parameters: wakeupTime: Specifies a timer wakeup source and the frequency of that source.
For PSoC 5LP this parameter is ignored.
Define
PM_ALT_ACT_TIME_NONE
PM_ALT_ACT_TIME_ONE_PPS
PM_ALT_ACT_TIME_CTW_2MS
PM_ALT_ACT_TIME_CTW_4MS
PM_ALT_ACT_TIME_CTW_8MS
PM_ALT_ACT_TIME_CTW_16MS
PM_ALT_ACT_TIME_CTW_32MS
PM_ALT_ACT_TIME_CTW_64MS
PM_ALT_ACT_TIME_CTW_128MS
PM_ALT_ACT_TIME_CTW_256MS
PM_ALT_ACT_TIME_CTW_512MS
PM_ALT_ACT_TIME_CTW_1024MS
PM_ALT_ACT_TIME_CTW_2048MS
PM_ALT_ACT_TIME_CTW_4096MS
PM_ALT_ACT_TIME_FTW(1-256)
Time
None
One PPS: 1 second
CTW: 2 ms
CTW: 4 ms
CTW: 8 ms
CTW: 16 ms
CTW: 32 ms
CTW: 64 ms
CTW: 128 ms
CTW: 256 ms
CTW: 512 ms
CTW: 1024 ms
CTW: 2048 ms
CTW: 4096 ms
FTW: 10 µs to 2.56 ms
The PM_ALT_ACT_TIME_FTW() macro takes an argument that specifies how
many increments of 10 µs to delay. For PSoC 3 silicon the valid range of values is
1 to 256.
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Power Management
CyPmAltAct (Continued)
Parameters: wakeupSource: Specifies a bitwise mask of wakeup sources. In addition, if a
wakeupTime has been specified, the associated timer will be included as a
wakeup source. The wakeup source configuration is restored before function exit.
For PSoC 5LP this parameter is ignored.
Define
Source
PM_ALT_ACT_SRC_NONE
PM_ALT_ACT_SRC_COMPARATOR0
PM_ALT_ACT_SRC_COMPARATOR1
PM_ALT_ACT_SRC_COMPARATOR2
PM_ALT_ACT_SRC_COMPARATOR3
PM_ALT_ACT_SRC_INTERRUPT
PM_ALT_ACT_SRC_PICU
PM_ALT_ACT_SRC_I2C
PM_ALT_ACT_SRC_BOOSTCONVERTER
PM_ALT_ACT_SRC_FTW
PM_ALT_ACT_SRC_VD
None
Comparator 0
Comparator 1
Comparator 2
Comparator 3
Interrupt
PICU
I2C
Boost Converter
Fast Time Wheel
High and Low Voltage
Detection
Central Time Wheel
One PPS
LCD
PM_ALT_ACT_SRC_CTW
PM_ALT_ACT_SRC_ONE_PPS
PM_ALT_ACT_SRC_LCD
Note CTW and One PPS wakeup signals are in the same mask bit. FTW and Low
Voltage Interrupt (LVI)/High Voltage Interrupt (HVI) wakeup signals are in the
same mask bit.
When specifying a Comparator as the wakeupSource, use an instance specific
define that will track with the specific comparator for that instance. As an example,
for a Comparator instance named "MyComp" the value to OR into the mask is:
MyComp_ctComp__CMP_MASK.
When CTW, FTW, or One PPS is used as a wakeup source, the
CyPmReadStatus function must be called upon wakeup, with the corresponding
parameter. Refer to the CyPmReadStatus API for more information.
Return Value: None
Side Effects and For PSoC 5LP, the wakeup source is not selectable. In this case the
Restrictions: wakeupSource argument is ignored and any of the available wakeup sources will
wake the device.
If a wakeupTime other than NONE is specified, then upon exit the state of the
specified timer will be left as specified by wakeupTime with the timer enabled and
the interrupt disabled. Also, the ILO 1 KHz (if CTW timer is used as wakeup time)
or ILO 100 KHz (if FTW timer is used as wakeup time) will be left started.
PSoC® Creator™ System Reference Guide, Document Number: 001-94480, Rev. **
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Power Management
void CyPmSleep(uint8 wakeupTime, uint16 wakeupSource)
Description: Puts the part into the Sleep state.
Note Before calling this function, you must manually configure the power mode of
the source clocks for the timer that is used as wakeup timer.
Note Before calling this function, you must prepare clock tree configuration for the
low power mode by calling CyPmSaveClocks(). And restore clock configuration
after CyPmSleep() execution by calling CyPmRestoreClocks(). See Power
Management section, Clock Configuration subsection of the System Reference
Guide for more information.
PSoC 3: Before switching to Sleep, if a wakeupTime other than NONE is specified, then
the appropriate timer state is configured as specified with the interrupt for that
timer disabled. The wakeup source will be the combination of the values specified
in the wakeupSource and any timer specified in the wakeupTime argument. Once
the wakeup condition is satisfied, then all saved state is restored and the function
returns in the Active state.
Note If the wakeupTime value is different from the previous value, the period
before the wakeup occurs can be significantly shorter than the specified time. If
the next call is made with the same wakeupTime value, then the wakeup will
occur with the specified period after the previous wakeup occurred.
If a wakeupTime other than NONE is specified, then upon exit the state of the
specified timer will be left as specified by wakeupTime with the timer enabled and
the interrupt disabled. If the CTW or One PPS is already configured for wakeup,
for example with the Sleep Timer or RTC components, then specify NONE for the
wakeupTime and include the appropriate source for wakeupSource.
PSoC 5LP: The wakeupTime parameter is not used and the only NONE can be specified. The
wakeup time must be configured with the component, Sleep Timer for CTW
intervals and RTC for 1PPS interval. The component must be configured to
generate an interrupt.
Parameters: wakeupTime: Specifies a timer wakeup source and the frequency of that source.
For PSoC 5LP, this parameter is ignored.
Define
Time
PM_SLEEP_TIME_NONE
PM_SLEEP_TIME_ONE_PPS
PM_SLEEP_TIME_CTW_2MS
PM_SLEEP_TIME_CTW_4MS
PM_SLEEP_TIME_CTW_8MS
PM_SLEEP_TIME_CTW_16MS
PM_SLEEP_TIME_CTW_32MS
PM_SLEEP_TIME_CTW_64MS
PM_SLEEP_TIME_CTW_128MS
PM_SLEEP_TIME_CTW_256MS
PM_SLEEP_TIME_CTW_512MS
PM_SLEEP_TIME_CTW_1024MS
PM_SLEEP_TIME_CTW_2048MS
PM_SLEEP_TIME_CTW_4096MS
None
One PPS: 1 second
CTW: 2 ms
CTW: 4 ms
CTW: 8 ms
CTW: 16 ms
CTW: 32 ms
CTW: 64 ms
CTW: 128 ms
CTW: 256 ms
CTW: 512 ms
CTW: 1024 ms
CTW: 2048 ms
CTW: 4096 ms
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Power Management
CyPmSleep (Continued)
Parameters: wakeupSource: Specifies a bitwise mask of wakeup sources. In addition, if a
wakeupTime has been specified, the associated timer will be included as a
wakeup source. The wakeup source configuration is restored before function exit.
Define
Source
PM_SLEEP_SRC_NONE
PM_SLEEP_SRC_COMPARATOR0
PM_SLEEP_SRC_COMPARATOR1
PM_SLEEP_SRC_COMPARATOR2
PM_SLEEP_SRC_COMPARATOR3
PM_SLEEP_SRC_PICU
PM_SLEEP_SRC_I2C
PM_SLEEP_SRC_BOOSTCONVERTER
PM_SLEEP_SRC_VD
None
Comparator 0
Comparator 1
Comparator 2
Comparator 3
PICU
I2C
Boost Converter
High and Low Voltage
Detection
Central Time Wheel
One PPS
LCD
PM_SLEEP_SRC_CTW
PM_SLEEP_SRC_ONE_PPS
PM_SLEEP_SRC_LCD
Note CTW and One PPS wakeup signals are in the same mask bit.
When specifying a Comparator as the wakeupSource, use an instance specific
define that will track with the specific comparator for that instance. As an example
for a Comparator instance named "MyComp" the value to OR into the mask is:
MyComp_ctComp__CMP_MASK.
When CTW or One PPS is used as a wakeup source, the CyPmReadStatus
function must be called upon wakeup, with the corresponding parameter. Refer to
the CyPmReadStatus API for more information.
Return Value: None
Side Effects and If a wakeupTime other than NONE is specified, then upon exit the state of the
Restrictions: specified timer will be left as specified by wakeupTime with the timer enabled and
the interrupt disabled. Also, the ILO 1 KHz (if CTW timer is used as wake up time)
will be left started.
The 1 kHz ILO clock is expected to be enabled to measure Hibernate/Sleep
regulator settling time after a reset. The hold-off delay is measured using rising
edges of the 1 kHz ILO.
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Power Management
void CyPmHibernate()
Description: Puts the part into the Hibernate state.
Before switching to Hibernate, the current status of the PICU wakeup source bit is
saved and then set. This configures the device to wake up from the PICU.
Make sure you have at least one pin configured to generate a PICU interrupt. For
pin Px.y, the register "PICU_INTTYPE_PICUx_INTTYPEy" controls the PICU
behavior. In the TRM, this register is "PICU[0..15]_INTTYPE[0..7]." In the Pins
component datasheet, this register is referred to as the IRQ option. Once the
wakeup occurs, the PICU wakeup source bit is restored and the PSoC returns to
the Active state.
Parameters: None
Return Value: None
Side Effects and Applications must wait 20 µs before re-entering hibernate or sleep after waking
Restrictions: up from hibernate. The 20 µs allows the sleep regulator time to stabilize before
the next hibernate / sleep event occurs. The 20 µs requirement begins when the
device wakes up. There is no hardware check that this requirement is met. The
specified delay should be done on ISR entry.
After wakeup PICU interrupt occurs, the Pin_ClearInterrupt() function (where
"Pin" is the instance name of the Pins component) must be called to clear the
latched pin events. This allows proper Hibernate mode entry and enables
detection of future events.
The 1 kHz ILO clock is expected to be enabled to measure Hibernate/Sleep
regulator settling time after a reset. The hold-off delay is measured using rising
edges of the 1 kHz ILO.
uint8 CyPmReadStatus(uint8 mask)
Description: Manages the Power Manager Interrupt Status Register. This register has the
interrupt status for the one pulse per second, CTW, and FTW timers. This
hardware register clears on read. To allow for only clearing the bits of interest and
preserving the other bits, this function uses a shadow register that retains the
state. This function reads the status register and ORs that value with the shadow
register. That is the value that is returned. Then the bits in the mask that are set
are cleared from this value and written back to the shadow register.
Note You must call this function within 1 ms (1 clock cycle of the ILO) after a
CTW event has occurred.
Parameters: mask: Bits in the shadow register to clear
Define
Source
CY_PM_FTW_INT
CY_PM_CTW_INT
CY_PM_ONEPPS_INT
Fast Time Wheel
Central Time Wheel
One Pulse Per Second
Return Value: Status. Same enumerated bit values as used for the mask parameter.
PSoC® Creator™ System Reference Guide, Document Number: 001-94480, Rev. **
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Power Management
PSoC 4 Implementation
The software should set EXT_VCCD bit in the PWR_CONTROL register when Vccd is shorted to Vddd
on the board. This impacts the chip internal state transitions where it is necessary to know whether Vccd
is connected or floating to achieve minimum current in low power modes.
Note Setting this bit turns off the active regulator and will lead to a system reset unless both Vddd and
Vccd pins are supplied externally. Refer to the device TRM for more information.
It is safe to call PM APIs from the ISR. The wakeup conditions for Sleep and DeepSleep low power
modes are illustrated in the table below:
Interrupts State
Unmasked
Masked
Condition
Wakeup
ISR Execution
IRQ priority > current level
IRQ priority ≤ current level
IRQ priority > current level
IRQ priority ≤ current level
Yes
No
Yes
No
Yes
No
No
No
Power Management APIs
void CySysPmSleep(void)
Description: Puts the part into the Sleep state. This is a CPU-centric power mode. It means that
the CPU has indicated that it is in “sleep” mode and its main clock can be
removed. It is identical to Active from a peripheral point of view. Any enabled
interrupts can cause wakeup from a Sleep mode.
Parameters: None
Return Value: None
Side Effects and None
Restrictions:
void CySysPmDeepSleep(void)
Description: Puts the part into the Deep Sleep state.
If firmware attempts to enter this mode before the system is ready (that is, when
PWR_CONTROL.LPM_READY = 0), then the device will go into Sleep mode
instead and automatically enter the originally intended mode when the hold-off
expires. The wakeup occurs when an interrupt is received from a DeepSleep or
Hibernate peripheral. For more details, see corresponding peripheral’s datasheet.
Parameters: None
Return Value: None
Side Effects and None
Restrictions:
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Power Management
void CySysPmHibernate(void)
Description: It puts the part into the Hibernate state. Only SRAM and UDBs are retained; most
internal supplies are off. Wakeup is possible from a pin or a hibernate comparator
only.
Parameters: None
Return Value: None
Side Effects and This function does not apply to the PSoC 4000 family.
Restrictions:
It is expected that the firmware has already frozen the IO-Cells using
CySysPmFreezeIo() function before the call to this function. If this is omitted the
IO-cells will be frozen in the same way as they are in the Active to Deep Sleep
transition, but will lose their state on wake up (because of the reset occurring at
that time).
Because all CPU state is lost, the CPU will start up at the reset vector. To save
firmware state through Hibernate low power mode, corresponding variable should
be defined with CY_NOINIT attribute. It prevents data from being initialized to zero
on startup. The interrupt cause of the hibernate peripheral is retained, such that it
can be either read by the firmware or cause an interrupt after the firmware has
booted and enabled the corresponding interrupt. To distinguish the wakeup from
the Hibernate mode and the general Reset event, the CySysPmGetResetReason()
function could be used.
void CySysPmStop(void)
Description: Puts the part into the Stop state. All internal supplies are off; no state is retained.
Wakeup from Stop is performed by toggling the wakeup pin (P0.7), causing a
normal Boot procedure to occur. To configure the wakeup pin, the Digital Input Pin
component should be placed on the schematic, assigned to the P0.7, and
resistively pulled up or down to the inverse state of the wakeup polarity. To
distinguish the wakeup from the Stop mode and the general Reset event,
CySysPmGetResetReason() function could be used. The wakeup pin is active low
by default. The wakeup pin polarity could be changed with the
CySysPmSetWakeupPolarity() function.
Parameters: None
Return Value: None
Side Effects and This function does not apply to the PSoC 4000 family.
Restrictions:
This function freezes IO cells implicitly. It is not possible to enter STOP mode
before freezing the IO cells. The IO cells remain frozen after awake from the Stop
mode until the firmware unfreezes them after booting explicitly with
CySysPmUnfreezeIo() function call.
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Power Management
void CySysPmSetWakeupPolarity(uint32 polarity)
Description: Wake up from stop mode is performed by toggling the wakeup pin (P0.7), causing
a normal boot procedure to occur. This function assigns the wakeup pin active
level. Setting the wakeup pin to this level will cause the wakeup from stop mode.
The wakeup pin is active low by default.
Parameters: polarity: Wakeup pin active level
Define
Description
CY_PM_STOP_WAKEUP_ACTIVE_LOW
CY_PM_STOP_WAKEUP_ACTIVE_HIGH
Logical zero will wake up the chip
Logical one will wake up the chip
Return Value: None
Side Effects and None
Restrictions:
uint32 CySysPmGetResetReason(void)
Description: Retrieves last reset reason - transition from OFF/XRES/STOP/HIBERNATE to
RESET state. Note that waking up from STOP using XRES will be perceived as
general RESET.
Parameters: None
Return Value: Reset reason
Define
Reset reason
CY_PM_RESET_REASON_UNKN
CY_PM_RESET_REASON_XRES
Unknown
Transition from OFF/XRES to
RESET
Transition/wakeup from
HIBERNATE to RESET
Transition/wakeup from STOP to
RESET
CY_PM_RESET_REASON_WAKEUP_HIB
CY_PM_RESET_REASON_WAKEUP_STOP
Side Effects and None
Restrictions:
void CySysPmFreezeIo(void)
Description: Freezes IO-Cells directly to save IO-Cell state on wake up from Hibernate or Stop
mode.
Parameters: None
Return Value: None
Side Effects and It is not required to call this function before entering Stop mode, since
Restrictions: CySysPmStop() function freezes IO-Cells implicitly.
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Power Management
void CySysPmUnfreezeIo(void)
Description: The IO-Cells remain frozen after awake from Hibernate or Stop mode until the
firmware unfreezes them after booting. The call of this function unfreezes IO-Cells
explicitly.
Parameters: None
Return Value: None
Side Effects and None
Restrictions:
void CySysPmSetWakeupHoldoff(uint32 hfclkFrequencyMhz)
Description: Sets the Deep Sleep wakeup time by scaling the hold-off to the HFCLK frequency.
This function must be called before increasing HFCLK clock frequency. It can
optionally be called after lowering HFCLK clock frequency in order to improve
Deep Sleep wakeup time.
It is functionally acceptable to leave the default hold-off setting, but Deep Sleep
wakeup time may exceed the specification.
This function is applicable only for the PSoC 4000 family.
Parameters: uint32 hfclkFrequencyMhz: The HFCLK frequency in MHz. For example, if IMO
frequency is 24 MHz, and HFCLK divider is 2, the function should be called with
parameter 12 (the SYSCLK divider value should not be taken into account).
Return Value: None
Side Effects and None
Restrictions:
Instance Low Power APIs
Most components have an instance-specific set of low power APIs that allow you to put the component
into its low power state. These functions are listed below generically. Refer to the individual datasheet for
specific information regarding register retention information if applicable.
void `=instance_name`_Sleep (void)
Description: The _Sleep() function checks to see if the component is enabled and saves that
state. Then it calls the _Stop() function and calls _SaveConfig() function to save the
user configuration.
• PSoC 3/PSoC 5LP: Call the _Sleep() function before calling the
CyPmSleep() or the CyPmHibernate() function.
• PSoC 4: Call the _Sleep() function before calling the CySysPmDeepSleep()
function.
Parameters: None
Return Value: None
Side Effects: None
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Power Management
void `=instance_name`_Wakeup (void)
Description: The _Wakeup() function calls the _RestoreConfig() function to restore the user
configuration. If the component was enabled before the _Sleep() function was
called, the _Wakeup() function will re-enable the component.
Parameters: None
Return Value: None
Side Effects: Calling the _Wakeup() function without first calling the _Sleep() or _SaveConfig()
function may produce unexpected behavior.
void `=instance_name`_SaveConfig(void)
Description: This function saves the component configuration. This will save non-retention
registers. This function will also save the current component parameter values, as
defined in the Configure dialog or as modified by appropriate APIs. This function is
called by the _Sleep() function.
Parameters: None
Return Value: None
Side Effects: None
void `=instance_name`_RestoreConfig(void)
Description: This function restores the component configuration. This will restore non-retention
registers. This function will also restore the component parameter values to what
they were prior to calling the _Sleep() function.
Parameters: None
Return Value: None
Side Effects: Calling this function without first calling the _Sleep() or _SaveConfig() function may
produce unexpected behavior.
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5
Interrupts
The APIs in this chapter apply to all architectures except as noted. Refer also to the Interrupt component
datasheet for more information about interrupts.
Note For PSoC 3, Keil C compiler run-time libraries do not disable interrupts. The only exception is found
in the C51 run-time library when using large reentrant functions. Interrupts are disabled for 4 CPU
instructions (8 CPU cycles) to adjust the large reentrant stack.
APIs
CyGlobalIntEnable
Description: Macro statement that enables interrupts using the global interrupt mask.
CyGlobalIntDisable
Description: Macro statement that disables interrupts using the global interrupt mask.
uint32 CyDisableInts()
Description: Disables all interrupts.
Parameters: None
Return Value: 32-bit mask of interrupts previously enabled
void CyEnableInts(uint32 mask)
Description: Enables all interrupts specified in the 32-bit mask.
Parameters: mask: 32-bit mask of interrupts to enable
Return Value: None
Note Interrupt service routines must follow the policy that they restore the CYDEV_INTC_CSR_EN
register bits and interrupt enable state (EA) to the way they were found on entry. The ISR does not need
to do anything special as long as it uses properly nested CyEnterCriticalSection() and
CyExitCriticalSection() function calls.
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Interrupts
void CyIntEnable(uint8 number)
Description: Enables the specified interrupt number.
Parameters: number: Interrupt number. Valid range: [0-31]
Return Value: None
Note Interrupt service routines must follow the policy that they restore the CYDEV_INTC_CSR_EN
register bits and interrupt enable state (EA) to the way they were found on entry. The ISR does not need
to do anything special as long as it uses properly nested CyEnterCriticalSection() and
CyExitCriticalSection() function calls.
void CyIntDisable(uint8 number)
Description: Disables the specified interrupt number.
Parameters: number: Interrupt number. Valid range: [0-31]
Return Value: None
Note Interrupt service routines must follow the policy that they restore the CYDEV_INTC_CSR_EN
register bits and interrupt enable state (EA) to the way they were found on entry. The ISR does not need
to do anything special as long as it uses properly nested CyEnterCriticalSection() and
CyExitCriticalSection() function calls.
uint8 CyIntGetState(uint8 number)
Description: Gets the enable state of the specified interrupt number.
Parameters: number: Interrupt number. Valid range: [0-31]
Return Value: Enable status: 1 if enabled, 0 if disabled
cyisraddress CyIntSetVector(uint8 number, cyisraddress address)
Description: Sets the interrupt vector of the specified interrupt number.
Parameters: number: Interrupt number. Valid range: [0-31]
address: Pointer to an interrupt service routine
Return Value: Previous interrupt vector value
cyisraddress CyIntGetVector(uint8 number)
Description: Gets the interrupt vector of the specified interrupt number.
Parameters: number: Interrupt number. Valid range: [0-31]
Return Value: Interrupt vector value
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Interrupts
cyisraddress CyIntSetSysVector(uint8 number, cyisraddress address)
Description: This function applies to ARM based processors only and therefore does not apply
to the PSoC 3 device. It sets the interrupt vector of the specified exception. These
exceptions in the ARM architecture operate similar to user interrupts, but are
specified by the system architecture of the processor. The number of each
exception is fixed. Note that the numbering of these exceptions is separate from
the numbering used for user interrupts.
Parameters: number: Exception number. Valid range: [0-15].
address: Pointer to an interrupt service routine
Return Value: Previous interrupt vector value
cyisraddress CyIntGetSysVector(uint8 number)
Description: This function applies to ARM based processors only and therefore does not apply
to the PSoC 3 device. It gets the interrupt vector of the specified exception. These
exceptions in the ARM architecture operate similar to user interrupts, but are
specified by the system architecture of the processor. The number of each
exception is fixed. Note that the numbering of these exceptions is separate from
the numbering used for user interrupts.
Parameters: number: Exception number. Valid range: [0-15].
Return Value: Interrupt vector value
void CyIntSetPriority(uint8 number, uint8 priority)
Description: Sets the priority of the specified interrupt number.
Parameters: number: Interrupt number. Valid range: [0-31]
priority: Interrupt priority. 0 is the highest priority. Valid range: [0-7]
Return Value: None
uint8 CyIntGetPriority(uint8 number)
Description: Gets the priority of the specified interrupt number.
Parameters: number: Interrupt number. Valid range: [0-31]
Return Value: Interrupt priority
void CyIntSetPending(uint8 number)
Description: Forces the specified interrupt number to be pending.
Parameters: number: Interrupt number. Valid range: [0-31]
Return Value: None
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Interrupts
void CyIntClearPending(uint8 number)
Description: Clears any pending interrupt for the specified interrupt number.
Parameters: number: Interrupt number. Valid range: [0-31]
Return Value: None
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6
Pins
In addition to the functionality provided for pins as part of the Pins component, a library of pin macros is
provided in the cypins.h file for the PSoC 3/PSoC 5LP devices. There is no library of pin macros available
for the PSoC 4 devices. These macros all make use of the port pin configuration register that is available
for every pin on the PSoC 3/PSoC 5LP device. The address of that register is provided in the
cydevice_trm.h file. Each of these pin configuration registers is named:
CYREG_PRTx_PCy
where x is the port number and y is the pin number within the port.
For PSoC 4, there are status registers, data output registers, and port configuration registers only, so the
macro takes two arguments: port register and pin number. Each port has these registers addresses
defined:
CYREG_PRTx_DR
CYREG_PRTx_PS
CYREG_PRTx_PC
The x is the port number, and the second argument is the pin number.
PSoC 3/PSoC 5LP APIs
uint8 CyPins_ReadPin(uint16/uint32 pinPC)
Description: Reads the current value on the pin (pin state, PS).
Parameters: pinPC: Port pin configuration register (uint16 PSoC 3, uint32 PSoC 5LP)
Return Value: Pin state
0: Logic low value
Non-0: Logic high value
void CyPins_SetPin(uint16/uint32 pinPC)
Description: Set the output value for the pin (data register, DR) to a logic high. Note that this
only has an effect for pins configured as software pins that are not driven by
hardware.
Parameters: pinPC: Port pin configuration register (uint16 PSoC 3, uint32 PSoC 5LP)
Return Value: None
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Pins
void CyPins_ClearPin(uint16/uint32 pinPC)
Description: Clear the output value for the pin (data register, DR) to a logic low. Note that this
only has an effect for pins configured as software pins that are not driven by
hardware.
Parameters: pinPC: Port pin configuration register (uint16 PSoC 3, uint32 PSoC 5)
Return Value: None
void CyPins_SetPinDriveMode(uint16/uint32 pinPC, uint8 mode)
Description: Sets the drive mode for the pin (DM).
Parameters: pinPC: Port pin configuration register (uint16 PSoC 3, uint32 PSoC 5LP)
mode: Desired drive mode
Define
Source
CY_PINS_DM_ALG_HIZ
CY_PINS_DM_DIG_HIZ
CY_PINS_DM_RES_UP
CY_PINS_DM_RES_DWN
CY_PINS_DM_OD_LO
CY_PINS_DM_OD_HI
CY_PINS_DM_STRONG
CY_PINS_DM_RES_UPDWN
Analog HiZ
Digital HiZ
Resistive pull up
Resistive pull down
Open drain - drive low
Open drain - drive high
Strong CMOS Output
Resistive pull up/down
Return Value: None
uint8 CyPins_ReadPinDriveMode(uint16/uint32 pinPC)
Description: Reads the drive mode for the pin (DM).
Parameters: pinPC: Port pin configuration register (uint16 PSoC 3, uint32 PSoC 5LP)
Return Value: Current drive mode for the pin
Define
Source
CY_PINS_DM_ALG_HIZ
CY_PINS_DM_DIG_HIZ
CY_PINS_DM_RES_UP
CY_PINS_DM_RES_DWN
CY_PINS_DM_OD_LO
CY_PINS_DM_OD_HI
CY_PINS_DM_STRONG
CY_PINS_DM_RES_UPDWN
Analog HiZ
Digital HiZ
Resistive pull up
Resistive pull down
Open drain - drive low
Open drain - drive high
Strong CMOS Output
Resistive pull up/down
void CyPins_FastSlew(uint16/uint32 pinPC)
Description: Set the slew rate for the pin to fast edge rate. Note that this only applies for pins in
strong output drive modes, not to resistive drive modes.
Parameters: pinPC: Port pin configuration register (uint16 PSoC 3, uint32 PSoC 5LP)
Return Value: None
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Pins
void CyPins_SlowSlew(uint16/uint32 pinPC)
Description: Set the slew rate for the pin to slow edge rate. Note that this only applies for pins
in strong output drive modes, not to resistive drive modes.
Parameters: pinPC: Port pin configuration register (uint16 PSoC 3, uint32 PSoC 5LP)
Return Value: None
PSoC 4 APIs
CY_SYS_PINS_READ_PIN(portPS, pin)
Description: Reads the current value on the pin (pin state, PS).
Parameters: portPS: Address of port pin status register (uint32). Definitions for each port are
provided in the cydevice_trm.h file in the form: CYREG_PRTx_PS, where x is a
port number 0 - 4.
pin: pin number 0 – 7.
Return Value: Pin state:
0: Logic low value
Non-0: Logic high value
CY_SYS_PINS_SET_PIN(portDR, pin)
Description: Set the output value for the pin (data register, DR) to a logic high.
Note that this only has an effect for pins configured as software pins that are not
driven by hardware.
Parameters: portDR: Address of port output pin data register (uint32). Definitions for each port
are provided in the cydevice_trm.h file in the form: CYREG_PRTx_DR, where x is
a port number 0 - 4.
pin: pin number 0 - 7.
Return Value: None
CY_SYS_PINS_CLEAR_PIN(portDR, pin)
Description: This macro sets the state of the specified pin to zero.
Parameters: portDR: Address of port output pin data register (uint32). Definitions for each port
are provided in the cydevice_trm.h file in the form: CYREG_PRTx_DR, where x is
a port number 0 - 4.
pin: pin number 0 – 7.
Return Value: None
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Pins
CY_SYS_PINS_SET_DRIVE_MODE(portPC, pin, mode)
Description: Sets the drive mode for the pin (DM).
Parameters: portPC: Address of port configuration register (uint32). Definitions for each port are
provided in the cydevice_trm.h file in the form: CYREG_PRTx_PC, where x is a
port number 0 - 4.
pin: pin number 0 – 7.
mode: Desired drive mode
Define
Source
CY_SYS_PINS_DM_ALG_HIZ
Analog HiZ
CY_SYS_PINS_DM_DIG_HIZ
Digital HiZ
CY_SYS_PINS_DM_RES_UP
Resistive pull up
CY_SYS_PINS_DM_RES_DWN
Resistive pull down
CY_SYS_PINS_DM_OD_LO
Open drain - drive low
CY_SYS_PINS_DM_OD_HI
Open drain - drive high
CY_SYS_PINS_DM_STRONG
Strong CMOS Output
CY_SYS_PINS_DM_RES_UPDWN
Resistive pull up/down
Return Value: None
CY_SYS_PINS_READ_DRIVE_MODE(portPC, pin)
Description: Reads the drive mode for the pin (DM).
Parameters: portPC: Address of port configuration register (uint32). Definitions for each port are
provided in the cydevice_trm.h file in the form: CYREG_PRTx_PC, where x is a
port number 0 - 4.
pin: pin number 0 – 7.
Return Value: Current drive mode for the pin
Define
Source
CY_SYS_PINS_DM_ALG_HIZ
Analog HiZ
CY_SYS_PINS_DM_DIG_HIZ
Digital HiZ
CY_SYS_PINS_DM_RES_UP
Resistive pull up
CY_SYS_PINS_DM_RES_DWN
Resistive pull down
CY_SYS_PINS_DM_OD_LO
Open drain - drive low
CY_SYS_PINS_DM_OD_HI
Open drain - drive high
CY_SYS_PINS_DM_STRONG
Strong CMOS Output
CY_SYS_PINS_DM_RES_UPDWN
Resistive pull up/down
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7
Register Access
A library of macros provides read and write access to the registers of the device. These macros are used
with the defined values made available in the generated cydevice_trm.h and cyfitter.h files. Access to
registers should be made using these macros and not the functions that are used to implement the
macros. This allows for device independent code generation.
PSoC 3 is an 8-bit architecture, so the processor does not have endianness. However, the compiler for an
8-bit architecture will implement endianness. For PSoC 3, the Keil compiler implements a big endian
(MSB in lowest address) ordering. The PSoC 4/PSoC 5LP processor architectures use little endian
ordering.
SRAM and Flash storage in all architectures is done using the endianness of the architecture and
compilers. However, the registers in all these chips are laid out in little endian order. These macros allow
register accesses to match this little endian ordering. If you perform operations on multi-byte registers
without using these macros, you must consider the byte ordering of the specific architecture. Examples
include usage of DMA to transfer between memory and registers, as well as function calls that are passed
an array of bytes in memory.
The PSoC 3 is an 8-bit processor, so all accesses will be done a byte at a time. The PSoC 5LP will
perform accesses using the appropriate 8-, 16- and 32-bit accesses. The PSoC 4 requires these
accesses to be aligned to the width of the transaction.
The PSoC 4 requires peripheral register accesses to match the hardware register size. Otherwise, the
peripheral might ignore the transfer and Hard Fault exception will be generated.
APIs
uint8 CY_GET_REG8(uint16/uint32 reg)
Description: Reads the 8-bit value from the specified register. For PSoC 3, the address must be
in the lower 64 K address range.
Parameters: reg: Register address (uint16 PSoC 3, uint32 PSoC 4/PSoC 5LP)
Return Value: Read value
void CY_SET_REG8(uint16/uint32 reg, uint8 value)
Description: Writes the 8-bit value to the specified register. For PSoC 3 the address must be in
the lower 64 K address range.
Parameters: reg: Register address (uint16 PSoC 3, uint32 PSoC 4/PSoC 5LP)
value: Value to write
Return Value: None
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Register Access
uint16 CY_GET_REG16(uint16/uint32 reg)
Description: Reads the 16-bit value from the specified register. This macro implements the byte
swapping required for proper operation. For PSoC 3 the address must be in the
lower 64 K address range.
Parameters: reg: Register address (uint16 PSoC 3, uint32 PSoC 4/PSoC 5LP)
Return Value: Read value
void CY_SET_REG16(uint16/uint32 reg, uint16 value)
Description: Writes the 16-bit value to the specified register. This macro implements the byte
swapping required for proper operation. For PSoC 3 the address must be in the
lower 64 K address range.
Parameters: reg: Register address (uint16 PSoC 3, uint32 PSoC 4/PSoC 5LP)
value: Value to write
Return Value: None
uint32 CY_GET_REG24(uint16/uint32 reg)
Description: Reads the 24-bit value from the specified register. This macro implements the byte
swapping required for proper operation. For PSoC 3 the address must be in the
lower 64 K address range.
Parameters: reg: Register address (uint16 PSoC 3, uint32 PSoC 4/PSoC 5LP)
Return Value: Read value
void CY_SET_REG24(uint16/uint32 reg, uint32 value)
Description: Writes the 24-bit value to the specified register. This macro implements the byte
swapping required for proper operation. For PSoC 3 the address must be in the
lower 64 K address range.
Parameters: reg: Register address (uint16 PSoC 3, uint32 PSoC 4/PSoC 5LP)
value: Value to write
Return Value: None
uint32 CY_GET_REG32(uint16/uint32 reg)
Description: Reads the 32-bit value from the specified register. This macro implements the byte
swapping required for proper operation. For PSoC 3 the address must be in the
lower 64 K address range.
Parameters: reg: Register address (uint16 PSoC 3, uint32 PSoC 4/PSoC 5LP)
Return Value: Read value
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void CY_SET_REG32(uint16/uint32 reg, uint32 value)
Description: Writes the 32-bit value to the specified register. This macro implements the byte
swapping required for proper operation. For PSoC 3 the address must be in the
lower 64 K address range.
Parameters: reg: Register address (uint16 PSoC 3, uint32 PSoC 4/PSoC 5LP)
value: Value to write
Return Value: None
uint8 CY_GET_XTND_REG8(uint32 reg)
Description: Reads the 8-bit value from the specified register. Supports the full address space
for PSoC 3, but requires more execution cycles than the standard register get
function. Identical to CY_GET_REG8 for PSoC 4/PSoC 5LP.
Parameters: reg: Register address
Return Value: Read value
void CY_SET_XTND_REG8(uint32 reg, uint8 value)
Description: Writes the 8-bit value to the specified register. Supports the full address space for
PSoC 3, but requires more execution cycles than the standard register set
function. Identical to CY_SET_REG8 for PSoC 4/PSoC 5LP.
Parameters: reg: Register address
value: Value to write
Return Value: None
uint16 CY_GET_XTND_REG16(uint32 reg)
Description: Reads the 16-bit value from the specified register. This macro implements the byte
swapping required for proper operation. Supports the full address space for PSoC
3, but requires more execution cycles than the standard register get function.
Identical to CY_GET_REG16 for PSoC 4/PSoC 5LP.
Parameters: reg: Register address
Return Value: Read value
void CY_SET_XTND_REG16(uint32 reg, uint16 value)
Description: Writes the 16-bit value to the specified register. This macro implements the byte
swapping required for proper operation. Supports the full address space for PSoC
3, but requires more execution cycles than the standard register set function.
Identical to CY_SET_REG16 for PSoC 4/PSoC 5LP.
Parameters: reg: Register address
value: Value to write
Return Value: None
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uint32 CY_GET_XTND_REG24(uint32 reg)
Description: Reads the 24-bit value from the specified register. This macro implements the byte
swapping required for proper operation. Supports the full address space for PSoC
3, but requires more execution cycles than the standard register get function.
Identical to CY_GET_REG24 for PSoC 4/PSoC 5LP.
Parameters: reg: Register address
Return Value: Read value
void CY_SET_XTND_REG24(uint32 reg, uint32 value)
Description: Writes the 24-bit value to the specified register. This macro implements the byte
swapping required for proper operation. Supports the full address space for PSoC
3, but requires more execution cycles than the standard register set function.
Identical to CY_SET_REG24 for PSoC 4/PSoC 5LP.
Parameters: reg: Register address
value: Value to write
Return Value: None
uint32 CY_GET_XTND_REG32(uint32 reg)
Description: Reads the 32-bit value from the specified register. This macro implements the byte
swapping required for proper operation. Supports the full address space for PSoC
3, but requires more execution cycles than the standard register get function.
Identical to CY_GET_REG32 for PSoC 4/PSoC 5LP.
Parameters: reg: Register address
Return Value: Read value
void CY_SET_XTND_REG32(uint32 reg, uint32 value)
Description: Writes the 32-bit value to the specified register. This macro implements the byte
swapping required for proper operation. Supports the full address space for PSoC
3, but requires more execution cycles than the standard register set function.
Identical to CY_SET_REG32 for PSoC 4/PSoC 5LP.
Parameters: reg: Register address
value: Value to write
Return Value: None
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8
DMA
The DMA files provide the API functions for the DMA controller, DMA channels and Transfer Descriptors.
This API is the library version, not the code that is generated when the user places a DMA component on
the schematic. The automatically generated code would use the APIs in this module.
Refer to the DMA component datasheet for more information.
Note The linked list of all the Transfer Descriptors to be allocated is created (by CyDmacConfigure()
function call from the startup code) only if a DMA component is placed onto the schematic.
PSoC 4 devices have no DMA capability.
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Flash and EEPROM
PSoC 3/PSoC 5LP Implementation
Flash Architecture
Flash memory in PSoC devices provides nonvolatile storage for user firmware, user configuration data,
bulk data storage, and optional error correcting code (ECC) data. The main flash memory area contains
up to 256 KB of user program space, depending on the device type.
Flash is organized as a set of arrays. Each array consists of 64, 128, or 256 rows. Each row contains 256
data bytes plus 32 bytes of ECC area. If ECC is not used, this space can store device configuration data
and bulk user data. User code may not be run out of the ECC flash memory section.
Flash Memory Array Structure
Row 0
Data (256 bytes)
ECC (32 bytes)
Row 1
Data
ECC
Row N
Data
ECC
PSoC 3 flash memory has the following features:

organized as one array of 64, 128, or 256 rows;

each row contains 256 data bytes plus 32 bytes for either ECC or data storage.
PSoC 5LP flash memory has the following features:

organized as either one array of 128 or 256 rows, or as multiple arrays of 256 rows each;

each row contains 256 data bytes plus 32 bytes for either ECC or data storage.
See the device datasheet and TRM for more information on Flash architecture.
The System tab of the PSoC Creator Design-Wide Resources (DWR) file contains configuration options
that define ECC area utilization:
DWR Option
ECC Function
Enable Error Correcting
Code (ECC)
ECC corrects one bit error and detect multiple bit errors per 8 bytes. ECC
area stores error correcting code data.
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Flash and EEPROM
DWR Option
ECC Function
Store Configuration
Data in ECC Memory
The device configuration data will be stored in ECC area to reduce main
FLASH memory usage. Error correction may not be used when this option
is enabled.
Note This option is always disabled for bootloader projects, as ECC area is
dedicated for bootloadable projects.
ECC function is disabled. The user data can be stored in the ECC area.
None
For more information on using ECC, refer to the Flash Program Memory chapter of the TRM.
PSoC devices include a flexible flash-protection model that prevents access and visibility to on-chip flash
memory. The device offers the ability to assign one of four protection levels to each row of flash:

Unprotected

Factory Upgrade

Field Upgrade

Full Protection
The required protection level can be selected using the Flash Security tab of the PSoC Creator DWR
file. Flash protection levels can only be changed by performing a complete flash erase. The Flash
programming APIs will fail to write a row with Full Protection level. For more information on protection
model, refer to the Flash Security Editor section in the PSoC Creator Help.
EEPROM Architecture
PSoC EEPROM memory is byte-addressable nonvolatile memory. The EEPROM is also organized as a
set of arrays. Both PSoC 3 and PSoC 5LP architectures have one EEPROM array, the size of which is
512 bytes, 1 KB, or 2 KB. The array consists of 32, 64, or 128 rows, depending on the device. Each row
contains 16 bytes of data.
Working with Flash and EEPROM
Flash and EEPROM are mapped into memory space and can be read directly. To get the address of the
first Flash / EEPROM row in a specified array ID, the array ID should be multiplied by array size, and
added to Flash / EEPROM base address. To access any row in the same array ID, the size of the row
should be multiplied by the desired row number and added to the first row address of the specified array.
Note When writing Flash, data in the instruction cache can become stale. Therefore, the cache data does
not correlate to the data just written to Flash. A call to CyFlushCache() is required to invalidate the data in
cache and force fresh information to be loaded from Flash.
The following table provides definitions of the device-specific Flash parameters:
Value
Description
CY_FLASH_BASE
CY_FLASH_SIZE
CY_FLASH_SIZEOF_ARRAY
CY_FLASH_SIZEOF_ROW
CY_FLASH_SIZEOF_ECC_ROW
CY_FLASH_NUMBER_ROWS
CY_FLASH_NUMBER_ARRAYS
The base address of the Flash memory.
The size of the Flash memory in bytes.
The size of a Flash array in bytes.
The size of a Flash row in bytes.
The size of the ECC row in bytes.
The number of Flash rows.
The number of Flash arrays.
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The EEPROM API provides the following device-specific definitions:
Value
Description
CY_EEPROM_BASE
CY_EEPROM_SIZE
CY_EEPROM_SIZEOF_ARRAY
CY_EEPROM_SIZEOF_ROW
CY_EEPROM_NUMBER_ROWS
CY_EEPROM_NUMBER_ARRAYs
The base address of the EEPROM memory.
The size of the EEPROM memory in bytes.
The size of an EEPROM array in bytes.
The size of an EEPROM row in bytes.
The number of EEPROM rows.
The number of EEPROM arrays.
Both Flash and EEPROM are programmed through the system performance controller (SPC). To interface
with the SPC, information is pushed into, and pulled from, a single register. The Flash/EEPROM specific
API provides unified approach to work with Flash as well as EEPROM and simplifies interacting with the
SPC by abstracting the details away.
In PSoC 3/PSoC 5LP devices, flash can be read either by the cache controller or the SPC. Flash write
can be performed only by SPC. Both SPC and cache cannot simultaneously access the flash memory. If
the cache controller tries to access flash at the same time as the SPC, then it must wait until the SPC
completes its flash access operation. The CPU, which accesses the flash memory through the cache
controller, is therefore also stalled in this circumstance. If a CPU code fetch has to be done from the flash
memory due to a cache miss condition, then the cache would have to wait till the SPC completes the
flash write operation. Thus the CPU code execution will also be halted till the flash write is complete.
It can take as many as 20 milliseconds to write to EEPROM or Flash. During this time the device should
not be reset, or unexpected changes may be made to portions of EEPROM or Flash. Reset sources
include XRES pin, software reset, and watchdog; care should be taken to make sure that these are not
inadvertently activated. Also, the low voltage detect circuits should be configured to generate an interrupt
instead of a reset.
PSoC devices have an on-chip temperature sensor that is used to measure the internal die temperature.
You must acquire the temperature at least once to use Flash and EEPROM write functions. If the
application will be used in an environment where the die temperature changes 10 °C or more, the
temperature should be refreshed to adjust the write times to the Flash for optimal performance. The die
temperature is obtained by calling the CySetTemp() function. This function queries SPC for the die
temperature and stores it in a global variable, which is used implicitly while performing Flash and
EEPROM write operations.
When programming Flash with error detection/correction function disabled (ECC flash space is used for
data storage), there are multiple methods for writing a row of data:

Use CyWriteRowFull() to write the entire row including ECC;

Use CyWriteRowData() to write the entire row without ECC;

Use CyWriteRowConfig() to write just the ECC memory.
If the Flash ECC feature is disabled, you also need to allocate the buffer and pass it into the
CySetFlashEEBuffer() function for both Flash and EEPROM programming. This buffer is used to store
intermediate data while communicating with the SPC. For more information on the buffer allocation, refer
to the CySetFlashEEBuffer() function description in the APIs section of this chapter.
Flash or EEPROM can be written by one row at a time by calling the CyWriteRowData() function. The first
parameter determines the Flash or EEPROM array. The number of arrays that are Flash and the number
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Flash and EEPROM
of arrays that are EEPROM are specific to the exact device selected. Refer to device TRM to determine
which array IDs are valid. The row numbering starts from 0 for each array ID.
Flash Programming Diagram
CyFlash_Start()
(optional)
Yes
ECC Enabled
No
CySetFlashEEBuffer()
CySetTemp()
Data row + ECC row
Data type
ECC row
Data row
CyWriteRowFull()
CyWriteRowData()
CyWriteRowConfig()
(ECC Disabled)
EEPROM Programming Diagram
CyEEPROM_Start()
Yes
ECC Enabled
No
CySetFlashEEBuffer()
CySetTemp()
CyWriteRowFull()
CyWriteRowData()
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Flash and EEPROM
Power Modes
For PSoC 3/PSoC 5LP devices, the power manager will not put the device into a low power state if the
system performance controller (SPC) is executing a command. The device will go into low power mode
after the SPC completes command execution.
Flash and EEPROM APIs
cystatus CySetTemp()
Description: Updates the static snapshot of current chip temperature value obtained from on-
chip temperature sensor. This function must be called once before executing a
series of Flash / EEPROM writing functions. In case the application will be used in
an environment where the die temperature changes significantly (10 °C or more),
care should be taken to keep the temperature snapshot value up-to-date to adjust
the write times to the Flash for optimal performance.
Parameters: None
Return Value: Status
Value
Description
CYRET_SUCCESS
CYRET_LOCKED
CYRET_UNKNOWN
Successful
Flash / EEPROM writing already in use
Failure
Side Effects and The function does not return until the SPC has returned to an idle state.
Restrictions:
cystatus CySetFlashEEBuffer(uint8 *buffer)
Description: Sets the buffer used for temporary storage of a complete row of flash plus
associated ECC used during writes to Flash and EEPROM. This buffer is only
necessary when Flash ECC is disabled.
Parameters: uint8 *buffer: Address of the allocated buffer with the size that equals sum of flash
and ECC row sizes.
Return Value: Status
Value
Description
CYRET_SUCCESS
CYRET_LOCKED
Successful
Flash / EEPROM writing already in use
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cystatus CyWriteRowFull(uint8 arrayId, uint16 rowAddress, uint8 *rowData,
uint16 rowSize)
Description: Allows a row to be erased and programmed.
If the array is a Flash array:
DWR Flash configuration
Description
Enable ECC – ON
Store Configuration Data in
ECC Memory – N/A
Enable ECC – OFF
Store Configuration Data in
ECC Memory – ON
Data are written to the flash row. The ECC for these data
are calculated and written automatically.
The size of the data equals the size of the flash row.
Data are written to both flash and ECC rows.
To prevent overwriting of the configuration data stored in
the ECC flash space, the size of the data must be equal
to the size of the flash row.
Data are written to both flash and ECC rows.
The size of the data equals the sum of flash row and
ECC row sizes.
Enable ECC – OFF
Store Configuration Data in
ECC Memory – OFF
If the array is an EEPROM array, the size of data equals EEPROM row size.
Parameters: uint8 arrayId: ID of the array to write. The type of write, Flash or EEPROM, is
determined from the array ID. The arrays in the part are sequential starting at the
first ID for the specific memory type. The array ID for the Flash memory lasts from
0x00 to 0x3F and for the EEPROM memory it lasts from 0x40 to 0x7F.
uint16 rowAddress: Row address within the specified arrayId.
uint8 *rowData: Address of the data to be programmed. Note This cannot be the
same buffer as allocated by CySetFlashEEBuffer() function.
uint16 rowSize: Number of bytes of row data
Return Value: Status
Value
Description
CYRET_SUCCESS
CYRET_LOCKED
CYRET_CANCELED
Other non-zero
Successful
Flash / EEPROM writing already in use
Command not accepted
Failure
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cystatus CyWriteRowData(uint8 arrayId, uint16 rowAddress, uint8 *rowData)
Description: Writes a row of Flash or EEPROM.
If the array is a Flash array:
DWR Flash configuration
Description
Enable ECC – ON
Store Configuration Data in
ECC Memory – N/A
Data are written to the flash row. The ECC for these
data are calculated and written automatically.
The size of the data that is passed to this function
equals the size of the flash row.
Data are written to the flash memory.
The data stored in ECC memory are preserved using
the buffer provided by CySetFlashEEBuffer() function.
Enable ECC – OFF
Store Configuration Data in
ECC Memory – ON/OFF
If the array is an EEPROM array, the size of data equals EEPROM row size.
Parameters: uint8 arrayId: ID of the array to write. The type of write, Flash or EEPROM, is
determined from the array ID. The arrays in the part are sequential starting at the
first ID for the specific memory type. The array ID for the Flash memory lasts from
0x00 to 0x3F and for the EEPROM memory it lasts from 0x40 to 0x7F.
uint16 rowAddress: Row address within the specified arrayId.
uint8 *rowData: Address of the data to be programmed.
Return Value: Status
Value
Description
CYRET_SUCCESS
CYRET_LOCKED
CYRET_CANCELED
Other non-zero
Successful
Flash / EEPROM writing already in use
Command not accepted
Failure
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Flash and EEPROM
cystatus CyWriteRowConfig(uint8 arrayId, uint16 rowAddress, uint8 *rowECC)
Description: Writes the ECC portion of a Flash. This function is only valid for Flash array IDs
(not for EEPROM).
DWR Flash configuration
Description
Enable ECC – ON
Store Configuration Data in
ECC Memory – N/A
Enable ECC – OFF
Store Configuration Data in
ECC Memory – ON
Enable ECC – OFF
Store Configuration Data in
ECC Memory – OFF
This function is not available for this configuration as
the ECC is stored in the ECC memory.
This function is not available for this configuration as
the Configuration Data are stored in the ECC
memory.
Data are written to the ECC row.
The data stored in Flash row are preserved using the
buffer provided by CySetFlashEEBuffer() function.
Parameters: uint8 arrayId: ID of the array to write. The arrays in the part are sequential starting
at the first ID for the specific memory type. The array ID for the Flash memory lasts
from 0x00 to 0x3F.
uint16 rowAddress: Row address within the specified arrayId.
uint8 *rowECC: Address of the data to be programmed.
Return Value: Status
Value
Description
CYRET_SUCCESS
CYRET_LOCKED
CYRET_CANCELED
Other non-zero
Successful
Flash / EEPROM writing already in use
Command not accepted
Failure
void CyFlash_Start()
Description: Enables the Flash. By default Flash is enabled.
Parameters: None
Return Value: None
void CyFlash_Stop()
Description: Disables the Flash. This setting is ignored as long as the CPU is currently running.
This will only take effect when the CPU is later disabled.
Parameters: None
Return Value: None
void CyFlash_SetWaitCycles(uint8 freq)
Description: Sets the number of clock cycles the cache will wait before it samples data coming
back from Flash. This function must be called before increasing CPU clock
frequency. It can optionally be called after lowering CPU clock frequency in order
to improve CPU performance.
Parameters: freq: CPU operation frequency in Megahertz.
Return Value: None
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Flash and EEPROM
void CyEEPROM_Start()
Description: Enables the EEPROM.
The EEPROM is controlled by a separate bit and must be started before it can be
used.
Parameters: None
Return Value: None
void CyEEPROM_Stop()
Description: Disables the EEPROM.
The EEPROM is controlled by a separate bit and can be stopped independently.
Parameters: None
Return Value: None
void CyEEPROM_ReadReserve()
Description: Request access to the EEPROM for reading and waits until that access is
available. The access to EEPROM is arbitrated between the controller that writes
to the EEPROM and the normal access to read from EEPROM. It is not required to
reserve access to the EEPROM for reading, but if a write is still active and a read
is attempted a fault is generated and the wrong data is returned.
Parameters: None
Return Value: None
void CyEEPROM_ReadRelease()
Description: Releases the read reservation of the EEPROM. If the EEPROM has been
reserved for reading, then it must be released before further writes to the
EEPROM can be performed.
Parameters: None
Return Value: None
PSoC 4 Implementation
Memory Architecture
PSoC 4 does not support EEPROM or the Flash ECC feature. The configuration of the Flash memory
varies by device, so the device-specific constants provided for the device must be used.
The following table provides definitions of the device-specific Flash parameters:
Value
Description
CY_FLASH_BASE
CY_FLASH_SIZE
CY_FLASH_SIZEOF_ARRAY
The base pointer of the Flash memory.
The size of the Flash memory in bytes.
The size of a Flash array in bytes.
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Value
Description
CY_FLASH_SIZEOF_ROW
CY_FLASH_NUMBER_ROWS
CY_FLASH_NUMBER_ARRAYS
The size of a Flash row in bytes.
The number of Flash rows.
The number of Flash arrays.
Working with Flash
Flash programming operations are implemented as system calls. System calls are executed out of SROM
in the privileged mode of operation. Users have no access to read or modify the SROM code. The CPU
requests the system call by writing the function opcode and parameters to the System Performance
Controller (SPC) input registers, and then requesting the SROM to execute the function. Based on the
function opcode, the SPC executes the corresponding system call from SROM and updates the SPC
status register. The CPU should read this status register for the pass/fail result of the function execution.
As part of function execution, the code in SROM interacts with the SPC interface to do the actual flash
programming operations.
It can take as many as 20 milliseconds to write to flash. During this time, the device should not be reset,
or unexpected changes may be made to portions of the flash. Reset sources include the XRES pin, a
software reset, and the watchdog. Make sure that these are not inadvertently activated. Also, the low
voltage detect circuits should be configured to generate an interrupt instead of a reset.
The flash can be read either by the cache controller or the SPC. Flash writes can be performed only by
the SPC. Both the SPC and the cache cannot simultaneously access flash memory. If the cache controller
tries to access flash at the same time as the SPC, then it must wait until the SPC completes its flash
access operation. The CPU, which accesses the flash memory through the cache controller, is therefore
also stalled in this circumstance. If a CPU code fetch has to be done from flash memory due to a cache
miss condition, then the cache would have to wait until the SPC completes the flash write operation. Thus
the CPU code execution will also be halted until the flash write is complete.
Flash is directly mapped into memory space and can be read directly.
Note: Flash write operations on the PSoC 4000 devices modify the clock settings of the device during the
period of the write operation. Refer to the CySysFlashWriteRow() API documentation for details.
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Flash APIs
cystatus CySysFlashWriteRow(uint32 rowNum, const uint8 rowData[])
Description: Writes a row of Flash.
Parameters: uint32 rowNum: Row number. The valid range is dependent on the device.
uint8 rowData: Array of bytes for a complete row to write.
Return Value: Status:
Value
Description
CYRET_SUCCESS
CYRET_LOCKED
CYRET_CANCELED
CYRET_BAD_PARAM
Other non-zero
Successful
Flash already in use
Command not accepted
One or more invalid parameters
Failure
Side Effects and The IMO must be enabled before calling this function. The operation of the flash
Restrictions: writing hardware is dependent on the IMO.
For PSoC 4000 devices this API will automatically modify the clock settings for the
device. Writing to flash requires that changes be made to the IMO and HFCLK
settings. The configuration is restored before returning. HFCLK will have several
frequency changes during the operation of this API between a minimum frequency
of the current IMO frequency divided by 8 and a maximum frequency of 12 MHz.
This will impact the operation of most of the hardware in the device.
void CySysFlashSetWaitCycles(uint32 freq)
Description: Sets the number of clock cycles the cache will wait before it samples data coming
back from Flash. This function must be called before increasing the SYSCLK clock
frequency. It can optionally be called after lowering the SYSCLK clock frequency
in order to improve CPU performance.
Parameters: freq: Valid range [3-48]. Frequency for operation of the IMO.
Note: Invalid frequencies will be ignored.
Return Value: None
Side Effects and None
Restrictions:
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10 Bootloader Migration
This chapter covers information about the bootloader architecture introduced with PSoC Creator 2.1, as
well as various known issues that you may encounter when migrating designs with the bootloader system
from PSoC Creator 2.0 or earlier.
Introduction
Beginning with PSoC Creator 2.1, the bootloader system has been reorganized to provide more
configuration options. In previous releases, the bootloader system was part of the cy_boot component (a
required component that is automatically and invisibly instantiated in all designs). The bootloader system
now includes two independent Bootloader and Bootloadable components. You can find the components in
the PSoC Creator Component Catalog, and they include component datasheets like all other
components.
Also, the bootloader system configuration options have been moved from the PSoC Creator Design-Wide
Resources (DWR) file into the corresponding Bootloader and Bootloadable component configuration
dialogs. See Migrating Bootloader Designs and Migrating Bootloadable Designs sections in this chapter
for more details.
The switch to the new bootloader system is performed automatically by updating the cy_boot component
to version 3.0 or above. However, some changes may impact your existing bootloader and bootloadable
designs. This will require maintenance when moving to the new bootloader system architecture. The
bootloader system configuration settings must be moved manually.
The three key migration alternatives include:

Complete Migration to PSoC Creator 2.1 or later

Migrating to PSoC Creator 2.1 or later without cy_boot Component Update

Migrating to PSoC Creator 2.1 or later for Bootloadable Designs
Complete Migration to PSoC Creator 2.1 or later
In this scenario, PSoC Creator 2.1 or later is used to work with the latest version of the cy_boot
component and new bootloader architecture.
When you open a project that was last saved in a previous PSoC Creator release, you will be prompted to
update components to the latest version.

Use the Component Update Tool and choose the latest version of the cy_boot component. It is
recommended that all components be updated together. Use the “Update All to Latest” button to
ensure the newest versions are selected for update.
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Bootloader Migration

Open the bootloader system design and place a Bootloader component onto the schematic for a
Bootloader or Multi-application bootloader application type. Place a Bootloadable component
onto the schematic for a Bootloadable application type. See Project Application Type Property
Changes for more information.

Transfer the bootloader system settings from the DWR file to the component configuration
dialogs. See Migrating Bootloader Designs and Migrating Bootloadable Designs for details.
Migrating to PSoC Creator 2.1 or later without cy_boot Component Update
In this scenario, PSoC Creator 2.1 or later is used to work with the bootloader system design that was
created in previous PSoC Creator releases. No any additional care is required in order to continue
working with the bootloader system.
All the components present on the design schematic can be updated to the latest available versions,
except the cy_boot component. The cy_boot component cannot be updated to the version 3.0 or above
without switching to the new bootloader architecture at the same time.
Note Some of the latest component versions shipped with PSoC Creator 2.1 or later require cy_boot
version 3.0 or above, so you cannot update them without updating cy_boot.
Migrating to PSoC Creator 2.1 or later for Bootloadable Designs Only
In this scenario, only the bootloadable project is migrated to PSoC Creator 2.1 or later and cy_boot 3.0 or
above. Existing bootloader designs are completely compatible with the newly created or migrated
bootloadable designs. PSoC Creator 2.1 or later without an updated cy_boot component or previous
PSoC Creator releases can be used for making changes to the bootloader design.
Migrating Bootloader Designs
The following table shows the correlation between the bootloader system in previous PSoC Creator
releases and the bootloader system introduced in PSoC Creator 2.1.
PSoC Creator releases before 2.1
PSoC Creator 2.1 or later with cy_boot 3.0 or above
(Bootloader section in the System tab of the DWR)
(Bootloader component)
IO Component
Communication component
Set by Application Type property of the design.
Refer to the Project Application Type Property
Changes section.
Wait for Command
Multi-application bootloader
Wait for Command Time (ms)
Wait for command time (ms)
Version
Bootloader application version
Packet Checksum Type
Packet checksum type
Fast Application Verification
Fast bootloadable application validation
N/A
Bootloader application validation
N/A
Optional commands
Wait for command
For more details about the PSoC Creator bootloader system features, refer to the Bootloader component
datasheet.
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Bootloader Migration
Migrating Bootloadable Designs
The following table shows the correlation between the bootloadable system introduced with PSoC Creator
2.1 versus releases before PSoC Creator 2.1.
PSoC Creator releases before 2.1
PSoC Creator 2.1 or later with cy_boot 3.0 or above
(Bootloadable section in the System tab of the DWR)
(Bootloadable component)
Version
Application version
Application ID
Application ID
Custom ID
Application custom ID
N/A
Manual application image placement
N/A
Placement address
Set in the Bootloader tab of the project’s
Dependencies window. Refer to the Project
Application Type Property Changes section.
Bootloader hex file (Dependencies tab of the
bootloader component's Configure dialog).
The CyBtldr_Load() function previously declared in the Bootloadable project was removed. Use the
Bootloadable_1_Load() function instead, where Bootloadable_1 is the instance name of the Bootloadable
component.
For more details about the PSoC Creator bootloader system features, refer to the Bootloadable
component datasheet.
Project Application Type Property Changes
In PSoC Creator releases prior to version 2.1, the Application Type option was used to choose the type
of the application that will be produced by a build of a project. Beginning with PSoC Creator 2.1, the
Application Type project property provides a way to verify that the design is created as intended.
The following table correlates the Application Type option value with the placed component
configuration:
Application Type
Expected Component
Bootloader
Bootloader component with Multi-application bootloader option disabled.
Multi App Bootloader
Bootloader component with Multi-application bootloader option enabled.
Bootloadable
Bootloadable component.
The Application Type option is set in the advanced section of the New Project dialog and can be
modified later in the project’s Build Settings window, under the Code Generation section.
Migrating Bootloadable Dependency to Bootloader Design
In PSoC Creator releases prior to version 2.1, the Bootloader tab of the project’s Dependencies window
was used to link the bootloadable project to the bootloader project. With the introduction of the
Bootloadable component in PSoC Creator 2.1 with cy_boot version 3.0 or above, this option was moved
to the Dependencies tab of the Bootloadable component Configure dialog. Refer to the component
datasheet for more information.
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11 System Functions
These functions apply to all architectures.
General APIs
uint8 CyEnterCriticalSection(void)
Description: CyEnterCriticalSection disables interrupts and returns a value indicating whether
interrupts were previously enabled (the actual value depends on the device
architecture).
Note Implementation of CyEnterCriticalSection manipulates the IRQ enable bit with
interrupts still enabled. The test and set of the interrupt bits is not atomic; this is true
for all architectures. Therefore, to avoid corrupting the processor state, it must be the
policy that all interrupt routines restore the interrupt enable bits as they were found
on entry.
Parameters: None
Return Value: uint8
PSoC 3 – Returns a value containing two bits:
bit 0: 1 if interrupts were enabled before CyEnterCriticalSection was called.
bit 1: 1 if IRQ generation was disabled before CyEnterCriticalSection was called.
PSoC 4/PSoC 5LP – Returns 0 if interrupts were previously enabled or 1 if interrupts
were previously disabled.
void CyExitCriticalSection(uint8 savedIntrStatus)
Description: CyExitCriticalSection re-enables interrupts if they were enabled before
CyEnterCriticalSection was called. The argument should be the value returned from
CyEnterCriticalSection.
Parameters: uint8 savedIntrStatus: Saved interrupt status returned by the CyEnterCriticalSection
function.
Return Value: None
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System Functions
void CYASSERT(uint32 expr)
Description: Macro that evaluates the expression and if it is false (evaluates to 0) then the
processor is halted. This macro is evaluated unless NDEBUG is defined. If NDEBUG
is defined, then no code is generated for this macro. NDEBUG is defined by default
for a Release build setting and not defined for a Debug build setting.
Parameters: expr: Logical expression. Asserts if false.
Return Value: None
void CyHalt(uint8 reason)
Description: Halts the CPU.
Parameters: reason: Value to be passed for debugging. This value may be useful to know the
reason why CyHalt() was invoked.
Return Value: None
void CySoftwareReset(void)
Description: Forces a software reset of the device.
Parameters: None
Return Value: None
CyDelay APIs
There are four CyDelay APIs that implement simple software-based delay loops. The loops compensate
for bus clock frequency.
The CyDelay functions provide a minimum delay. If the processor is interrupted, the length of the loop will
be extended by as long as it takes to implement the interrupt. Other overhead factors, including function
entry and exit, may also affect the total length of time spent executing the function. This will be especially
apparent when the nominal delay time is small.
void CyDelay(uint32 milliseconds)
Description: Delay by the specified number of milliseconds. By default the number of cycles to
delay is calculated based on the clock configuration entered in PSoC Creator. If
the clock configuration is changed at run-time, then the function CyDelayFreq is
used to indicate the new Bus Clock frequency. CyDelay is used by several
components, so changing the clock frequency without updating the frequency
setting for the delay can cause those components to fail.
Parameters: milliseconds: Number of milliseconds to delay.
Return Value: None
Side Effects and CyDelay has been implemented with the instruction cache assumed enabled.
Restrictions: When instruction cache is disabled on PSoC 5LP, CyDelay will be two times
larger. For example, with instruction cache disabled CyDelay(100) would result in
about 200 ms delay instead of 100 ms.
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void CyDelayUs(uint16 microseconds)
Description: Delay by the specified number of microseconds. By default the number of cycles
to delay is calculated based on the clock configuration entered in PSoC Creator.
If the clock configuration is changed at run-time, then the function CyDelayFreq is
used to indicate the new Bus Clock frequency. CyDelayUs is used by several
components, so changing the clock frequency without updating the frequency
setting for the delay can cause those components to fail.
Parameters: microseconds: Number of microseconds to delay.
Return Value: Void
Side Effects and CyDelayUS has been implemented with the instruction cache assumed enabled.
Restrictions: When instruction cache is disabled on PSoC 5LP, CyDelayUs will be two times
larger. For example, with instruction cache disabled CyDelayUs(100) would result
in about 200 us delay instead of 100 us.
If the bus clock frequency is a small non-integer number, the actual delay can be
up to twice as long as the nominal value. The actual delay cannot be shorter than
the nominal one.
void CyDelayFreq(uint32 freq)
Description: Sets the Bus Clock frequency used to calculate the number of cycles needed to
implement a delay with CyDelay. By default the frequency used is based on the
value determined by PSoC Creator at build time.
Parameters: freq: Bus clock frequency in Hz.
0: Use the default value
non-0: Set frequency value
Return Value: None
void CyDelayCycles(uint32 cycles)
Description: Delay by the specified number of cycles using a software delay loop.
Parameters: cycles: Number of cycles to delay.
Return Value: None
PSoC 3/PSoC 5LP Voltage Detect APIs
Voltage monitoring circuits in these devices can be configured to generate an interrupt when Vdda or
Vddd is outside a defined range. Low-voltage interrupts are available for both the analog and digital
supplies, and a high-voltage interrupt is available for the analog supply. The trip levels for the low-voltage
detectors are independently configurable. The trip level for the high-voltage detector is fixed at 5.75 V.
The analog and digital low-voltage monitoring circuits can also be configured to reset the device instead
of generating an interrupt.
Bits [2:0] in the RESET_CR1 register control whether or not the voltage monitoring circuits generate an
interrupt if the supply is outside the trip level. If the LVI interrupts are enabled, then bits [7:6] in
RESET_CR3 control whether or not the device is reset when a low-voltage event occurs. The LVI resets
are part of the precision reset circuit and generate a momentary hardware POR reset.
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The status of the voltage monitor circuits is stored in two different registers. Bits [2:0] of the RESET_SR0
register are set to 1 if a low-voltage or high-voltage event has occurred. This register is cleared when read
or upon POR reset. Bits [2:0] of the RESET_SR2 register hold the real-time status of the voltage monitor
circuits’ outputs, which means they will only be set to ‘1’ for the duration that the event is occurring.
The GlobalSignalRef component can be used to connect the LVI and HVI interrupt signals to other
components in the project schematic, or an interrupt component if you wish to execute an interrupt on an
LVI/HVI event. If “Low/High Voltage Detect (LVI/HVI)” is selected in the component, the output of
GlobalSignalRef is set to 1 whenever any of the enabled LVI or HVI circuits detect an event. The output
will remain at 1 as long as an LVI or HVI event is occurring. Refer to the GlobalSignalRef component
datasheet for more information.
The following API functions configure and manage the voltage monitoring circuits and associated interrupt
status registers. For more information on the voltage monitoring circuits, refer to the Voltage Monitoring
section of the device TRM and the Power Voltage Level Monitors section of the device datasheet.
void CyVdLvDigitEnable(uint8 reset, uint8 threshold)
Description: Enables the output of the digital low-voltage monitor when Vddd is at or below the
trip point, selects whether or not the device generates an interrupt or resets the
part upon the low voltage event, and sets the voltage trip level.
Parameters: reset: Enables device reset on digital LVI interrupt:
• Interrupt on digital LVI event
• Non-zero - Reset on digital LVI event
threshold: Sets the trip point of the digital low-voltage monitoring circuit in steps
of approximately 250 mV in range from 1.70 V (0x00) to 5.45 V (0x0F).
Return Value: None
Side Effects and The LVI resets are momentary. When an LVI reset occurs, the RESET_CR1 and
Restrictions RESET_CR3 registers are restored to their default values. This means that the
LVI circuit is no longer enabled and the device exits reset. If the supply is below
the trip level and firmware enables the LVI reset functionality, the device will reset
again. This will continue as long as the supply is below the trip level or as long as
the user enables the reset functionality of the LVI.
When any LVI reset occurs, the RESET_SR0 and RESET_SR2 status registers
are cleared. This means that the Analog LVI, Digital LVI, and Analog HVI status
bits are not persistent across any LVI reset.
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void CyVdLvAnalogEnable(uint8 reset, uint8 threshold)
Description: Enables the output of the analog low-voltage monitor when Vdda is at or below the
trip point, selects whether or not the device generates an interrupt or resets the
part upon the low voltage event, and sets the voltage trip level.
Parameters: reset: Enables device reset on analog LVI interrupt:
• 0 - Interrupt on analog LVI event
• Non-zero - Reset on analog LVI event.
threshold: Sets the trip point of the analog low-voltage monitoring circuit in steps
of approximately 250 mV in range from 1.70 V (0x00) to 5.45 V (0x0F).
Return Value: None
Side Effects and The LVI resets are momentary. When an LVI reset occurs, the RESET_CR1 and
Restrictions RESET_CR3 registers are restored to their default values. This means that the
LVI circuit is no longer enabled and the device exits reset. If the supply is below
the trip level and firmware enables the LVI reset functionality, the device will reset
again. This will continue as long as the supply is below the trip level or as long as
the user enables the reset functionality of the LVI.
When any LVI reset occurs, the RESET_SR0 and RESET_SR2 status registers
are cleared. This means that the Analog LVI, Digital LVI, and Analog HVI status
bits are not persistent across any LVI reset.
void CyVdLvDigitDisable(void)
Description: Disables the digital low voltage monitor (interrupt and device resets are
disabled).
Parameters: None
Return Value: None
Side Effects and Interrupt and LVI resets are disabled, but pending interrupts and status bits are
Restrictions not cleared.
void CyVdLvAnalogDisable(void)
Description: Disables the analog low voltage monitor (interrupt and device resets are
disabled).
Parameters: None
Return Value: None
Side Effects and Interrupt and LVI resets are disabled, but pending interrupts and status bits are
Restrictions not cleared.
void CyVdHvAnalogEnable(void)
Description: Enables the analog high voltage monitor to generate an interrupt on 5.75 V
threshold detection for Vdda.
Parameters: None
Return Value: None
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void CyVdHvAnalogDisable(void)
Description: Disables the analog high voltage monitor (interrupt is disabled).
Parameters: None
Return Value: None
Side Effects and Interrupt and HVI resets are disabled, but pending interrupts and status bits are
Restrictions not cleared.
uint8 CyVdStickyStatus(uint8 mask)
Description: Reads and clears the voltage detection status bits in the RESET_SR0 register.
The bits are set to 1 by the voltage monitor circuit when the supply is outside the
detector’s trip point. They stay set to 1 until they are read or a POR / LVI / PRES
reset occurs. This function uses a shadow register, so only the bits passed in the
parameter will be cleared in the shadow register.
Parameters: mask: Bits in the RESET_SR0 shadow register to clear and return.
Value
Definition
CY_VD_LVID Persistent status of digital LVI.
CY_VD_LVIA Persistent status of analog LVI.
CY_VD_HVIA Persistent status of analog HVI.
Register [bits]
RESET_SR0 [0]
RESET_SR0 [1]
RESET_SR0 [2]
Return Value: Status. Same enumerated bit values as used for the mask parameter. A zero is
returned for bits not used in the mask parameter.
Side Effects and When an LVI reset occurs, the RESET_SR0 status registers are cleared. This
Restrictions means that the voltage detection status bits are not persistent across an LVI
reset and cannot be used to determine a reset source.
uint8 CyVdRealTimeStatus(void)
Description: Reads the real-time voltage detection status bits in the RESET_SR2 register.
The bits are set to 1 by the voltage monitor circuit when the supply is outside the
detector’s trip point, and set to 0 when the supply is inside the trip point.
Parameters: None
Return Value: Status of the LVID, LVIA, and HVIA bits in the RESET_SR2 register.
Value
Definition
Register [bits]
CY_VD_LVID Real-time status of digital LVI. RESET_SR0 [0]
CY_VD_LVIA Real-time status of analog LVI. RESET_SR0 [1]
CY_VD_HVIA Real-time status of analog HVI. RESET_SR0 [2]
Side Effects and When an LVI reset occurs, the RESET_SR2 status registers are cleared. This
Restrictions means that the voltage detection status bits are not persistent across an LVI
reset and cannot be used to determine a reset source.
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PSoC 4100 and 4200 Voltage Detect APIs
void CySysLvdEnable(uint32 threshold)
Description: Enables the output of the low-voltage monitor when Vddd is at or below the trip
point, configures device to generate an interrupt, and sets the voltage trip level.
Parameters: threshold: Threshold selection for Low Voltage Detect circuit. Threshold variation
is +/- 2.5% from these typical voltage choices.
Define
Voltage threshold
CY_LVD_THRESHOLD_1_75_V
CY_LVD_THRESHOLD_1_80_V
CY_LVD_THRESHOLD_1_90_V
CY_LVD_THRESHOLD_2_00_V
CY_LVD_THRESHOLD_2_10_V
CY_LVD_THRESHOLD_2_20_V
CY_LVD_THRESHOLD_2_30_V
CY_LVD_THRESHOLD_2_40_V
CY_LVD_THRESHOLD_2_50_V
CY_LVD_THRESHOLD_2_60_V
CY_LVD_THRESHOLD_2_70_V
CY_LVD_THRESHOLD_2_80_V
CY_LVD_THRESHOLD_2_90_V
CY_LVD_THRESHOLD_3_00_V
CY_LVD_THRESHOLD_3_20_V
CY_LVD_THRESHOLD_4_50_V
1.75 V
1.80 V
1.90 V
2.00 V
2.10 V
2.20 V
2.30 V
2.40 V
2.50 V
2.60 V
2.70 V
2.80 V
2.90 V
3.00 V
3.20 V
4.50 V
Return Value: None
void CySysLvdDisable(void)
Description: Disables the low voltage detection. Low voltage interrupt is disabled.
Parameters: None
Return Value: None
uint32 CySysLvdGetInterruptSource(void)
Description: Gets the low voltage detection interrupt status (without clearing).
Parameters: None
Return Value: Interrupt request value:
CY_SYS_LVD_INT - Indicates an Low Voltage Detect interrupt
void CySysLvdClearInterrupt(void)
Description: Clears the low voltage detection interrupt status.
Parameters: None
Return Value: None
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Cache Functionality
PSoC 3
The PSoC 3 cache is enabled by default. It can be disabled using the PSoC Creator Design-Wide
Resources System Editor. There are no defines, functions or macros for cache handling for PSoC 3.
PSoC 5LP
void CyFlushCache()
Description: Flushes the PSoC 5/PSoC 5LP cache by invalidating all entries.
Parameters: None
Return Value: None
Side Effects and When writing Flash, data in the instruction cache can become stale. Therefore, the
Restrictions: cache data does not correlate to the data just written to Flash. A call to
CyFlushCache() is required to invalidate the data in cache and force fresh
information to be loaded from Flash.
PSoC 4
PSoC 4 devices have no cache capability.
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12 Startup and Linking
The cy_boot component is responsible for the startup of the system. The following functionality has been
implemented:

Provide the reset vector

Setup processor for execution

Setup interrupts

Setup the stack including the reentrant stack for the 8051

Configure the device

Initialize static and global variables with initialization values

Clear all remaining static and global variables

Integrate with the bootloader functionality

Preserve the reset status

Call main() C entry point
See application note AN60616 for more details on PSoC 3 and PSoC 5LP startup.
The device startup procedure configures the device to meet datasheet and PSoC Creator project
specifications. Startup begins after the release of a reset source, or after the end of a power supply ramp.
There are two main portions of startup: hardware startup and firmware startup. During hardware startup,
the CPU is halted, and other resources configure the device. During firmware startup, the CPU runs code
generated by PSoC Creator to configure the device. When startup ends, the device is fully configured,
and its CPU begins execution of user-authored main() code.
The hardware startup configures the device to meet the general performance specifications given in the
datasheet. The hardware startup phase begins after a power supply ramp or reset event. There are two
phases of hardware startup: reset and boot. After hardware startup ends, code execution from Flash
begins.
Firmware startup configures the PSoC device to behave as described in the PSoC Creator project. It
begins at the end of hardware startup. The PSoC device’s CPU begins executing user-authored main()
code after the completion of firmware startup. The main task of firmware startup is to populate
configuration registers such that the PSoC device behaves as designed in the PSoC Creator project. This
includes configuring analog and digital peripherals, as well as system resources such as clocks and
routing.
The startup procedure may be altered to better fit a specific application’s needs. There are two ways to
modify device startup: using the PSoC Creator design-wide resources (DWR) interface, and modifying the
device startup code.
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PSoC 3
Startup is all handled by a single assembly file (KeilStart.a51), which is based on a template provided by
Keil. There isn’t a file specifically associated with linking. The linker directives are used instead. For more
information on the 8051 architecture, refer to the Language Extensions section on www.keil.com.
For the more information on the PSoC 3’s architecture refer to the AN54181.
PSoC 4/PSoC 5LP
The startup and linker scripts have been custom developed by Cypress, but both of the toolchain vendors
that we currently support provide example linker implementations and complete libraries that solve many
of the issues that have been created by our custom implementations.
The memory layout of the final binary and hex images, as well as the placement in PSoC 5LP memory is
described in the linker descriptor (.scat) file generated as part of the PSoC Creator build. The custom
linker descriptor file can be used when building the project instead of the default one by going to Build
Settings window and specifying path to the file in the Custom Linker Script field of the Linker category.
For the more information on the PSoC 5LP’s CPU architecture, refer to the Cortex™-M3 Technical
Reference Manual on infocenter.arm.com. There is also Application Note 179 - Cortex™ -M3 Embedded
Software Development on infocenter.arm.com.
For the more information on the PSoC 4’s CPU architecture, refer to the Cortex™-M0 Technical
Reference Manual on infocenter.arm.com.
Unaligned Transfers (PSoC 5LP)
The PSoC 5LP supports unaligned transfers on single accesses with a number of limitations common for
Cortex-M3 platform. When unaligned transfers are used, they are actually converted into multiple aligned
transfers. This conversion is transparent from the software point of view. When an unaligned transfer
takes place, it is broken into separate transfers. So, it takes more clock cycles for a single data access. To
get the best performance and to ensure code compatibility through PSoC processors family, the
unaligned transfers should be avoided.
In PSoC 5LP, SRAM is located at Cortex-M3 Code/SRAM regions boundary. The unaligned accesses that
cross memory map boundaries are architecturally unpredictable. The linker configuration files used for
PSoC 5LP do not protect against unaligned accesses that cross this boundary.
When unaligned accesses must be used, use a function that checks for the possible boundary problem
and do byte accesses at the boundary or modify the linker script to force the memory that needs to be
accessed in an unaligned fashion to not span this border.
GCC Implementation
PSoC Creator integrates the GCC ARM Embedded compiler including making the Newlib-nano and
newlib libraries. Refer to the Red Hat newlib C Library for the C library reference manual.
The newlib-nano is configured by default. To choose newlib library, open the Build Settings dialog >
ARM GCC 4.7.3 > Linker > General, and set the “Use newlib-nano” option to False.
By default, with the GNU ARM compiler, the string formatting functions in the C run-time library return
empty strings for floating-point conversions. The newlib-nano library is a stripped-down version of the full
C newlib. It does not include support for floating point formatting and other memory-intensive features.
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There are two solutions to this problem: enable floating-point formatting support in newlib-nano, or
change the library to the full newlib.
To enable floating-point formatting, open the Build Settings dialog, go to the Linker page, and add the
string -u _printf_float to the command line options. This change will result in an increase in Flash
and RAM usage in your application.
Note If you also wish to use the scanf functions with floating-point numbers you should add the string
–u _scanf_float as well, with another increase in Flash and RAM usage.
Realview Implementation (applicable for MDK and RVDS)
Use all the standard libraries (C standardlib, C microlib, fplib, mathlib). All of these libraries are linked in
by default.

Support for RTOS and user replacement of routines. This is possible because the library routines
are denoted as "weak" allowing their replacement if another implementation is provided.

A mechanism is provided that allows for the replacement of the provided linker/scatter file with a
user version. This is implemented by allowing the user to create the file local to their project and
having a build setting that allows the specification of this file as the linker/scatter file instead of the
file provided automatically.

Currently the heap and stack size are specified as a fixed quantity (4 K Stack, 1 K Heap). If
possible the requirement to specify Heap and Stack sizes should be removed entirely. If that is
not possible, then these values should be the defaults with the option to choose other values in
the Design-Wide Resources GUI.

All the code in the Generated Source tree is compiled into a single library as part of the build
process. Then that compiled library is linked in with the user code in the final link.
CMSIS Support
Cortex Microcontroller Software Interface Standard (CMSIS) is a standard from ARM for interacting with
Cortex M-series processors. There are multiple levels of support. The Core Peripheral Access Layer
(CMSIS Core) support is provided. For the more information refer to CMSIS - Cortex Microcontroller
Software Interface Standard on www.arm.com.
PSoC Creator 3.0 provides support for CMSIS Core version 3.20. Also, PSoC Creator 3.0 provides the
ability to use a custom version of the CMSIS Core.
The following diagram shows how CMSIS Core version 3.20 files are integrated into the cy_boot
component and how custom version of CMSIS Core files can be integrated.
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core_cm4_simd.h
core_cmInstr.h
core_cmInstr.h
core_cmFunc.h
core_cmFunc.h
core_cm3.h
core_<cpu>.h
core_cm3_psoc5.h
<device>.h
Cm3RealView.scat
(cm3gcc.ld)
startup_<device>.s
Cm3Start.c
system_<device>.h
system_<device>.c
main.c
cy_boot
CMSIS v3.20
<user>.c/c++
CMSIS-CORE
Device Files (Cypress)
CMSIS-CORE
Standard Files (ARM)
User Program
CMSIS custom
version
The following describe each file from the diagram:

The Cm3Start.c and cm3gcc.ld files (part of the cy_boot component) contain Cortex-M3 device
startup code and interrupt vector tables and completely substitute CMSIS startup_<device>.s
template file.

Vendor-specific device file <device>.h that includes CMSIS Core standard files is represented in
cy_boot component by core_cm3_psoc5.h.

The core_cmInstr.h file defines intrinsic functions to access special Cortex-M instructions and
core_cmFunc.h file provides functions to access the Cortex-M core peripherals. These files were
added since CMSIS Core version 2.0.

The core_cm4_simd.h file added to the CMSIS SIMD Instruction Access is relevant for Cortex-M4
only.

system_<device>.h, system_<device>.c – Generic files for system configuration (i.e. processor
clock and memory bus system), are partially covered by Cm3Start.c.
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Manual addition of the CMSIS Core files
Beginning with PSoC Creator 2.2, the “Include CMSIS Core Peripheral Library Files” option is added to
the System tab of the DWR file. By default, this option is enabled and CMSIS Core version 3.20 files are
added to the project. This option should be disabled if you wish to manually add CMSIS Core files.
Un-check “Include CMSIS Core Peripheral Library Files” option on the System tab of the DWR file to
detach CMSIS 3.20 files from the cy_boot component.
Add the following CMSIS Core files to the project:

core_cmInstr.h

core_cmFunc.h

core_cm3.h
Based on the CMSIS vendor-specific template file (<device>.h), create device header file, copy device
specific definitions from core_cm3_psoc5.h file and add following definitions at the top of the file:
#include <cytypes.h>
#define __CHECK_DEVICE_DEFINES
#define __CM3_REV
0x0201
#define __MPU_PRESENT
#define __NVIC_PRIO_BITS
#define __Vendor_SysTickConfig
0
3
0
Include the previously created vendor-specific device header file to the application.
Preservation of Reset Status
PSoC 3/PSoC 5LP
The value of the reset status register (RESET_SR0) is read and cleared any time the device is booted.
That value is saved to a global SRAM variable. Note that the IPOR, PRES, and LVI reset sources clear
the RESET_SR0 register, and the WDT, Software reset and XRES reset sources preserve the
RESET_SR0 register. For more information, refer to the device datasheet and TRM.
Some PSoC 3 devices perform an additional software reset. If any other than a software device reset
previously occurred, it will reload the NVLs and apply the correct settings. This operation is transparent to
the normal boot process and will not interfere with bootloading, debugging, or normal device functionality.
See the device errata for more information.
To retain user-defined status that persists through many resets, use the CY_RESET_GP0 and
CY_RESET_GP1 bits in the RESET_SR0 register. The CyResetStatus variable is used to obtain value of
these bits after a device reset. These bits are used by Bootloader and Bootloadable projects and cannot
be used by user.
uint8 CyResetStatus
Name
Description
CY_RESET_LVID
CY_RESET_LVIA
Low voltage detect digital
Low voltage detect analog
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Name
Description
CY_RESET_HVIA
CY_RESET_WD
CY_RESET_SW
CY_RESET_GP0
CY_RESET_GP1
High voltage detect analog
Watchdog reset
Software reset
General purpose bit 0
General purpose bit 1
PSoC 4
uint32 CySysGetResetReason(uint32 reason)
Description: The function returns the cause for the latest reset(s) that occurred in the system
and clears those that are defined with the parameter.
All bits in the RES_CAUSE register assert when the corresponding reset cause
occurs and must be cleared by firmware. These bits are cleared by hardware only
during XRES, POR, or a detected brown-out.
Parameters: reason: bits in the RES_CAUSE register to clear.
Define
Source
CY_SYS_RESET_WDT
CY_SYS_RESET_PROTFAULT
CY_SYS_RESET_SW
WDT
Protection Fault
Software reset
Return Value: Status. Same enumerated bit values as used for the reason parameter.
Side Effects and None
Restrictions:
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13 Watchdog Timer
PSoC 3/PSoC 5LP
void CyWdtStart(uint8 ticks, uint8 lpMode)
Description: Enables the watchdog timer. The timer is configured for the specified count
interval, the CTW is cleared, the setting for low power mode is configured, and the
watchdog timer is enabled.
The hardware implementation of the watchdog timer prevents any modification of
the timer once it has been enabled. It also prevents the timer from being disabled
once it has been enabled. This protects the watchdog timer from changes caused
by errant code. As a result, only the first call to CyWdtStart() after reset will have
any effect.
The watchdog counts each time the CTW reaches the period specified. The
watchdog must be cleared using the CyWdtClear() function before the watchdog
counts to three. The CTW is free running, so this will occur after between 2 and 3
timer periods elapse.
Parameters: ticks: One of the four available timer periods. Once WDT enabled, the interval
cannot be changed.
Define
Time
CYWDT_2_TICKS
CYWDT_16_TICKS
CYWDT_128_TICKS
CYWDT_1024_TICKS
4 – 6 ms
32 – 48 ms
256 – 384 ms
2.048 – 3.072 s
void CyWdtStart(uint8 ticks, uint8 lpMode) (continued)
Parameters lpMode: Low power mode configuration.
Define
Effect
CYWDT_LPMODE_NOCHANGE
CYWDT_LPMODE_MAXINTER
CYWDT_LPMODE_DISABLED
No Change
Switch to longest timer mode during sleep / hibernate
Disable WDT during sleep / hibernate
Return Value: None
void CyWdtClear()
Description: Clears (feeds) the watchdog timer.
Parameters: None
Return Value: None
PSoC® Creator™ System Reference Guide, Document Number: 001-94480, Rev. **
95
Watchdog Timer
PSoC 4100 and PSoC 4200
PSoC 4100 and PSoC 4200 Functional Description
The WDT asserts an interrupt or a hardware reset to the device after a preprogrammed interval, unless it
is periodically serviced in firmware. The WDT has two 16- bit counters (Counter-0 and Counter-1) and
one 32-bit counter (Counter-2).
These counters can be configured to work independently or in cascade. The cascade configuration
provides an option to increase the reset or interrupt interval.
Interrupt Logic
Interrupt to
Reset Counter
(3 counts)
Counter-1
(16-bit)
Interrupt to
Reset Counter
(3 counts)
Device Reset Logic
Counter-0
(16-bit)
Counter-2
(32-bit)
The Counter-0 and Counter-1 generate an interrupt or a reset on reaching the specified terminal count for
the first time, or generate a reset after three continuous unhandled interrupt, whereas Counter-2 only
generates an interrupt. The interrupt must be cleared after entering the Interrupt Service Routine (ISR) in
firmware by calling CySysWdtClearInterrupt() with the corresponding parameter.
The Counter-0 and Counter-1 perform action when the corresponding counter value equals
corresponding match value configured by call to CySysWdtWriteMode(). The Counter-2 perform action
when the bit defined by call to CySysWdtWriteToggleBit() is toggled in Counter-2. For example, if toggle
bit is bit number 7 (configured by call to the CySysWdtWriteToggleBit(7) function), the Counter-2 will
generate one interrupt per 2^7=128 WDT clocks.
Power Modes
In the Active mode, the interrupt request from the WDT is sent to the CPU via IRQ 9. In the Sleep or Deep
Sleep power mode the CPU subsystem is powered-down, so the interrupt request from the WDT is
directly sent to the WakeUp Interrupt Controller (WIC), which will then wake up the CPU. Then, the CPU
acknowledges the interrupt request and executes the Interrupt Service Routine (ISR).
Enabling or disabling a WDT requires three LFCLK cycles to come into effect. During that period the
SYSCLK clock should be available. That means the device should be not put into Deep Sleep mode
during that period.
After waking from Deep Sleep, an internal timer value is set to zero until the ILO loads the register with
the correct value. This led to an increase in low-power mode current consumption. The work around is to
wait for the first positive edge of the ILO clock before allowing the WDT_CTR_* registers to be read by
CySysWdtReadCount() function.
PSoC® Creator™ System Reference Guide, Document Number: 001-94480, Rev. **
96
Watchdog Timer
Clock Source
The WDT is clocked by LFCLK sourced by the 32 kHz ILO. By default, this oscillator is enabled by PSoC
Creator on device startup. Therefore, the ILO is enabled by WDT API that accesses WDT registers.
According to the device datasheet, the ILO accuracy is +/-60% over voltage and temperature. This means
that the timeout period may vary by 60% from the configured. Appropriate margins should be added while
configuring WDT intervals to make sure that unwanted device resets does not occur on some devices.
Please refer to the device datasheet for the more information on oscillator accuracy.
Register Locking
Accidental corruption of the WDT configuration can be prevented by setting the bit-field WDT_LOCK of
the CLK_SELECT register by calling the CySysWdtLock() function. When WDT is locked, any writing to
the WDT_* and CLK_ILO* registers is ignored.
The CySysWdtUnlock() function should be called in order to allow WDT registers modification.
Clearing WDT
The LFCLK clock is asynchronous to the SYSCLK. So, generally, it takes 3 LFCLK cycles for the WDT
registers changes to come into effect. This is important to remember that WDT should be cleared at least
4 cycles (3 + 1 for sure) before timeout occurs, especially when small match values / low toggle bit
numbers are used.
The WDT counters should be cleared by calling the CySysWdtResetCounters() function with the
parameter corresponding to the counters whose values are going to be cleared.
It is recommended to clear WDT counters from the portion of the code that is not directly associated with
the WDT interrupt. It is possible that the main function of the firmware has crashed or is in an endless
loop, but that the WDT interrupt vector is still intact and the WDT is getting serviced properly.
Reset Detection
The CySysResetReason() function can be used to detect if the watchdog has triggered device reset.
Interrupt Configuration
The Global Signal Reference and Interrupt components can be used for the ISR configuration. If the WDT
is configured to generate interrupt, the pending interrupts must be cleared within ISR (otherwise, the
interrupt will be generated continuously):

Pending interrupt to the interrupt controller must be cleared by the call to the
WDTISR_ClearPending() function, where WDTISR is the instance name of the interrupt
component.

Pending interrupt to the WDT block must be cleared by the call to the CySysWdtClearInterrupt()
function. The call to the function will clear the unhandled WDT interrupt counter, if WDT is
configured to be in “generate interrupts and reset on 3rd unhandled interrupt” mode.
It is recommended to use WDT ISR as timer to trigger certain actions and to change the next WDT match
value.
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Watchdog Timer
PSoC 4100 and PSoC 4200 APIs
void CySysWdtLock(void)
Description: Locks out configuration changes to the Watchdog timer registers and ILO
configuration register.
Parameters: None
Return Value: None
Side Effects and This API enables the ILO, if it was disabled. After this API is called, the ILO can't
Restrictions: be disabled until calling of CySysWdtUnlock().
void CySysWdtUnlock(void)
Description: Unlocks the Watchdog Timer configuration register.
Parameters: None
Return Value: None
Side Effects and This API enables the ILO, if it was disabled.
Restrictions:
void CySysWdtWriteMode(uint32 counterNum, uint32 mode)
Description: Writes the mode of one of the three WDT counters. If WDT mode is not
configured, WDT timers are in a free running mode.
Parameters: counterNum: Valid range [0-2]. Number of the WDT counter.
mode: Mode of operation for the counter:
Define
Mode
CY_SYS_WDT_MODE_NONE
CY_SYS_WDT_MODE_INT
Free running
Interrupt generated on match for counter 0
and 1, and on bit toggle for counter 2
Reset on match (valid for counter 0 and 1
only)
Generate an interrupt and generate a reset
rd
on the 3 unhandled interrupt. (valid for
counter 0 and 1 only)
CY_SYS_WDT_MODE_RESET
CY_SYS_WDT_MODE_INT_RESET
Return Value: None
Side Effects and WDT counter counterNum should be disabled to set mode. Otherwise this function
Restrictions: call will have no effect. If the specified counter is enabled, call CySysWdtDsiable()
function with the corresponding parameter to disable specified counter and wait for
it to stop. This may take up to three LFCLK cycles.
This API enables the ILO, if it was disabled.
uint32 CySysWdtReadMode(uint32 counterNum)
Description: Reads the mode of one of the three WDT counters.
Parameters: counterNum: Valid range [0-2]. Number of the WDT counter.
Return Value: Mode of the counter. Same enumerated values as mode parameter used in
CySysWdtWriteMode().
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Watchdog Timer
void CySysWdtWriteClearOnMatch(uint32 counterNum, uint32 enable)
Description: Configures the WDT counter clear on a match setting. If configured to clear on
match the counter will count from 0 to the MatchValue giving it a period of
(MatchValue + 1).
Parameters: counterNum: Valid range [0-1]. Number of the WDT counter. Match values are not
supported by counter 2.
enable: 0 to disable, 1 to enable
Return Value: None
Side Effects and WDT counter counterNum should be disabled. Otherwise this function call will
Restrictions: have no effect. If the specified counter is enabled, call CySysWdtDsiable() function
with the corresponding parameter to disable specified counter and wait for it to
stop. This may take up to three LFCLK cycles.
This API enables the ILO, if it was disabled.
uint32 CySysWdtReadClearOnMatch(uint32 counterNum)
Description: Reads the clear on match setting for the specified counter.
Parameters: counterNum: Valid range [0-1]. Number of the WDT counter. Match values are not
supported by counter 2.
Return Value: Clear on Match status: 1 if enabled, 0 if disabled.
void CySysWdtEnable(uint32 counterMask)
Description: Enables the specified WDT counters. All counters specified in the mask are
enabled.
Parameters: counterMask: Mask of all counters to enable:
Define
Counter
CY_SYS_WDT_COUNTER0_MASK
CY_SYS_WDT_COUNTER1_MASK
CY_SYS_WDT_COUNTER2_MASK
0
1
2
Return Value: None
Side Effects and Enabling or disabling a WDT requires three LF clock cycles to come into effect.
Restrictions: Therefore, the WDT enable state must not be changed more than once in that
period.
After WDT is enabled, it is illegal to write WDT configuration (WDT_CONFIG) and
control (WDT_CONTROL) registers. That means that all WDT functions that
contain ‘write’ in the name (with the exception of CySysWdtWriteMatch() function)
are illegal to call once WDT enabled.
This API enables the ILO, if it was disabled.
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99
Watchdog Timer
void CySysWdtDisable(uint32 counterMask)
Description: Disables the specified WDT counters. All counters specified in the mask are
disabled.
Parameters: counterMask: Mask of all counters to disable:
Define
Counter
CY_SYS_WDT_COUNTER0_MASK
CY_SYS_WDT_COUNTER1_MASK
CY_SYS_WDT_COUNTER2_MASK
0
1
2
Return Value: None
Side Effects and Enabling or disabling a WDT requires three LF clock cycles to come into effect.
Restrictions: Therefore, the WDT enable state must not be changed more than once in that
period.
This API enables the ILO, if it was disabled.
uint32 CySysWdtReadEnabledStatus (uint32 counterNum)
Description: Reads the enabled status of one of the three WDT counters.
Parameters: counterNum: Valid range [0-2]. Number of the WDT counter.
Return Value: Status of WDT counter:
0 - counter is disabled, 1 - counter is enabled
Side Effects and This API returns actual WDT counter status from status register. It may take up to
Restrictions: Three LFCLK cycles since WDT counter was enabled for WDT status register to
contain actual data.
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100
Watchdog Timer
void CySysWdtWriteCascade(uint32 cascadeMask)
Description: Writes the two WDT cascade values based on the combination of mask values
specified.
Parameters: cascadeMask: Mask value used to set or clear both of the cascade values:
Define
Counter
CY_SYS_WDT_CASCADE_NONE
CY_SYS_WDT_CASCADE_01
CY_SYS_WDT_CASCADE_12
Neither
Cascade 01
Cascade 12
To set both cascade modes, two defines should be ORed:
(CY_SYS_WDT_CASCADE_01 | CY_SYS_WDT_CASCADE_12)
Return Value: None
Side Effects and If only one cascade mask is specified, the second cascade is disabled. To set both
Restrictions: cascade modes, two defines should be ORed:
(CY_SYS_WDT_CASCADE_01 | CY_SYS_WDT_CASCADE_12)
WDT counters that are part of the specified cascade, should be disabled.
Otherwise this function call will have no effect. If the specified counter is enabled,
call CySysWdtDsiable() function with the corresponding parameter to disable
specified counter and wait for it to stop. This may take up to three LFCLK cycles.
This API enables the ILO, if it was disabled.
uint32 CySysWdtReadCascade(void)
Description: Reads the two WDT cascade values returning a mask of the bits set.
Parameters: None
Return Value: Mask of cascade values set:
Define
Cascade
CY_SYS_WDT_CASCADE_NONE
CY_SYS_WDT_CASCADE_01
CY_SYS_WDT_CASCADE_12
Neither
Cascade 01
Cascade 12
void CySysWdtWriteMatch(uint32 counterNum, uint32 match)
Description: Configures the WDT counter match comparison value.
Parameters: counterNum: Valid range [0-1]. Number of the WDT counter. Match values are not
supported by counter 2.
match: Valid range [0-65535]. Value to be used to match against the counter.
Return Value: None
Side Effects and This API enables the ILO, if it was disabled.
Restrictions:
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101
Watchdog Timer
void CySysWdtWriteToggleBit(uint32 bits)
Description: Configures which bit in the WDT Counter 2 to monitor for a toggle. When that bit
toggles, an interrupt is generated if the mode for Counter 2 has interrupts enabled.
Parameters: bit: Valid range [0-31]. Counter 2 bit to monitor for a toggle.
Return Value: None
Side Effects and WDT Counter 2 should be disabled. Otherwise this function call will have no effect.
Restrictions: If the specified counter is enabled, call CySysWdtDsiable() function with the
corresponding parameter to disable specified counter and wait for it to stop. This
may take up to three LFCLK cycles.
This API enables the ILO, if it was disabled.
uint32 CySysWdtReadToggleBit(void)
Description: Reads which bit in the WDT counter 2 is monitored for a toggle.
Parameters: None
Return Value: Bit that is monitored (range of 0 to 31).
uint32 CySysWdtReadMatch(uint32 counterNum)
Description: Reads the WDT counter match comparison value.
Parameters: counterNum: Valid range [0-1]. Number of the WDT counter. Match values are not
supported by counter 2. Changes may take up to three LFCLK to be applied.
Return Value: 16-bit match value.
uint32 CySysWdtReadCount(uint32 counterNum)
Description: Reads the current WDT counter value.
Parameters: counterNum: Valid range [0-2]. Number of the WDT counter.
Return Value: Live counter value. Counter 0 and 1 are 16 bit counters and counter 2 is a 32 bit
counter.
uint32 CySysWdtGetInterruptSource(void)
Description: Reads a mask containing all the WDT interrupts that are currently set.
Parameters: None
Return Value: Mask of interrupts set:
Define
Counter
CY_SYS_WDT_COUNTER0_INT
CY_SYS_WDT_COUNTER1_INT
CY_SYS_WDT_COUNTER2_INT
0
1
2
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Watchdog Timer
void CySysWdtClearInterrupt(uint32 counterMask)
Description: Clears all WDT counter interrupts set in the mask. Calling this API also prevents
Reset from happening when counter mode is set to generate 3 interrupts and then
reset device. All WDT interrupts are to be cleared by firmware, otherwise interrupts
will be generated continuously.
Parameters: counterMask: Mask of all counters to enable:
Define
Counter
CY_SYS_WDT_COUNTER0_INT
CY_SYS_WDT_COUNTER1_INT
CY_SYS_WDT_COUNTER2_INT
0
1
2
Return Value: None
Side Effects and This API enables the ILO, if it was disabled; temporarily removes the Watchdog
Restrictions: lock, if it was set; and restores the lock state, after cleaning WDT interrupts that
were set in mask.
void CySysWdtResetCounters(uint32 counterMask)
Description: Resets all WDT counters set in the mask.
Parameters: counterMask: Mask of all counters to reset:
Define
Counter
CY_SYS_WDT_COUNTER0_RESET
CY_SYS_WDT_COUNTER1_RESET
CY_SYS_WDT_COUNTER2_RESET
0
1
2
Return Value: None
Side Effects and This API enables the ILO, if it was disabled. This API call will not reset counter
Restrictions: values if the Watchdog is locked.
PSoC 4000
Note It is highly recommended to enable WDT if the power supply can produce sudden brownout events
that may compromise the CPU functionality. This ensures that, after a brown-out compromises the CPU
functionality, the system will always recover.
PSoC 4000 Functional Description
The WDT asserts an interrupt or a hardware reset to the device after a preprogrammed interval, unless it
is periodically serviced in firmware. The WDT is a 16- bit free-running up-counter.
Interrupt to
Reset Counter
(3 counts)
Device Reset Logic
Interrupt Logic
Counter
(16-bit)
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103
Watchdog Timer
The WDT generates an interrupt when the count value in the counter equals the configured match value.
It is important to take into considerations that the counter is not reset on match. When the counter
reaches match value, it generates an interrupt and then keeps counting up till it overflows and rolls back
to zero and reaches the match value again at which point another interrupt is generated.
WDT
Counter
Value
1st
unhandled
interrupt
2nd
unhandled
interrupt
3rd
unhandled
interrupt and
device reset
2(16-NumberOfIgnoreBits)
WDT Match Value
Time
WDT
Enabled
WDT
Counter
Overflow
WDT
Counter
Overflow
In case of the intention to use WDT for a periodic interrupt generation, the match value should be
incremented in the ISR. As a result, the next WDT interrupt will be generated when the counter reaches
the new match value.
Also some functionality is added to reduce entire WDT counter period, by specifying the number of most
significant bits that are cut-off in the WDT counter. For example, if the CySysWdtWriteIgnoreBits()
function called with parameter 3, the WDT counter becomes a 13-bit free-running up-counter.
The WDT reset period can be calculated using following equation:
WDTRe setTime = 2 * ( LFCLK
* (2
Period
(16 − NumberOfIgnoreBits )
)) + ( LFCLK
Period
* WDT
)
MatchValue
Power Modes
In the Active mode, the interrupt request from the WDT is sent to the CPU via IRQ 4. In the Sleep or Deep
Sleep power mode the CPU subsystem is powered-down, so the interrupt request from the WDT is
directly sent to the WakeUp Interrupt Controller (WIC), which will then wake up the CPU. Then, the CPU
acknowledges the interrupt request and executes the Interrupt Service Routine (ISR).
Enabling or disabling a WDT requires three LFCLK cycles to come into effect. During that period the
SYSCLK clock should be available. That means that the device should not be put into Deep Sleep mode
during that period.
After waking from Deep Sleep, an internal timer value is set to zero until the ILO loads the register with
the correct value. This led to an increase in low-power mode current consumption. The work around is to
wait for the first positive edge of the ILO clock before allowing the WDT_CTR_* registers to be read by
CySysWdtReadCount() function.
PSoC® Creator™ System Reference Guide, Document Number: 001-94480, Rev. **
104
Watchdog Timer
Clock Source
The WDT is clocked by the LFCLK sourced by the 32 kHz ILO. The WDT reset must be disabled before
disabling the ILO. Otherwise, any register write to disable the ILO will be ignored. Enabling the WDT reset
will automatically enable the ILO.
According to the device datasheet, the ILO accuracy is +/-60% over voltage and temperature. This means
that the timeout period may vary by 60% from the configured. An appropriate margin should be added
while configuring WDT intervals to make sure that unwanted device resets do not occur on some devices.
Please refer to the device datasheet for the more information on oscillator accuracy.
Register Locking
This feature is not available for the device.
Clearing WDT
The LFCLK clock is asynchronous to the SYSCLK. So, generally, it takes three LFCLK cycles for the
WDT registers changes to come into effect. This is important to remember that WDT should be cleared at
least four cycles (3 LFCLK cycles + 1 to be sure) before timeout occurs, especially when small match
values / low toggle bit number are used.
It is recommended to clear WDT counters from the portion of the code that is not directly associated with
the WDT interrupt. It is possible that the main function of the firmware has crashed or is in an endless
loop, but that the WDT interrupt vector is still intact and the WDT is getting serviced properly.
Reset Detection
The CySysResetReason() function can be used to detect if the watchdog has triggered device reset.
Interrupt Configuration
The Global Signal Reference and Interrupt components can be used for the ISR configuration. If the WDT
is configured to generate interrupt, the pending interrupts must be cleared within ISR (otherwise, the
interrupt will be generated continuously):
•
Pending interrupt to the interrupt controller must be cleared by the call to the
WDTISR_ClearPending() function, where WDTISR is the instance name of the interrupt
component.
•
Pending interrupt to the WDT block must be cleared by the call to the CySysWdtClearInterrupt()
function. The call to the function will clear the unhandled WDT interrupt counter, if WDT is
rd
configured to be in “generate interrupts and reset on 3 unhandled interrupt” mode.
It is recommended to use WDT ISR as timer to trigger certain actions and to change the next WDT match
value.
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105
Watchdog Timer
PSoC 4000 APIs
uint32 CySysWdtReadEnabledStatus(void)
Description: Reads the enabled status WDT counter.
Parameters: None
Return Value: Status of WDT counter:
0 - counter is disabled
1 - counter is enabled
Side Effects and None
Restrictions:
void CySysWdtEnable(void)
Description: Enables the WDT counter.
Parameters: None
Return Value: None
Side Effects and This API enables ILO, if it was disabled.
Restrictions:
void CySysWdtWriteMatch(uint32 match)
Description: Configures the WDT counter match comparison value.
Parameters: match:
Valid range [0-65535]. Value to be used to match against the counter.
Return Value: None
Side Effects and This API enables ILO, if it was disabled.
Restrictions:
uint32 CySysWdtReadMatch(void)
Description: Reads the WDT counter match comparison value.
Parameters: None
Return Value: Counter match value.
uint32 CySysWdtReadCount(void)
Description: Reads the current WDT counter value.
Parameters: None
Return Value: Live counter value.
Side Effects and None
Restrictions:
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106
Watchdog Timer
void CySysWdtWriteIgnoreBits(uint32 bitsNum)
Description: Configures the number of MSB bits of the watchdog timer that are not checked
against match.
Parameters: bitsNum: Valid range [0-15]. Number of MSB bits.
Return Value: None
Side Effects and The value of bitsNum provides control over the time-to-reset of the watchdog
Restrictions: (which happens after 3 successive matches).
uint32 CySysWdtReadIgnoreBits(void)
Description: Reads the number of MSB bits of the watchdog timer that are not checked against
match.
Parameters: None
Return Value: Number of MSB bits.
Side Effects and None
Restrictions:
void CySysWdtClearInterrupt(void)
Description: Cleans WDT match flag, which is set every time WDT counter reaches WDT
match value.
Parameters: None
Return Value: None
Side Effects and Clearing this bit also feeds the watch dog. Missing 2 interrupts in a row will
Restrictions: generate brown-out reset.
void CySysWdtMaskInterrupt(void)
Description: After masking interrupts from WDT, they are not passed to CPU.
Parameters: None
Return Value: None
Side Effects and This API does not disable the WDT reset generation on 2 missed interrupts.
Restrictions:
void CySysWdtUnmaskInterrupt(void)
Description: Unmasks WDT interrupts.
Parameters: None
Return Value: None
Side Effects and None
Restrictions:
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Watchdog Timer
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108
14 MISRA Compliance
This chapter describes the MISRA-C:2004 compliance and deviations for the PSoC Creator cy_boot
component and code generated by PSoC Creator.
MISRA stands for Motor Industry Software Reliability Association. The MISRA specification covers a set of
122 mandatory rules and 20 advisory rules that apply to firmware design and has been put together by
the Automotive Industry to enhance the quality and robustness of the firmware code embedded in
automotive devices.
There are two types of deviations defined:

project deviations – deviations that are applicable for all PSoC Creator components

specific deviations – deviations that are applicable for the specific component
This section provides information on the following items:

Verification Environment

Project Deviations

Documentation Related Rules

PSoC Creator Generated Sources Deviations

cy_boot Component-Specific Deviations
Verification Environment
This section provides MISRA compliance analysis environment description.
Component
Name
Version
Test Specification
MISRA-C:2004 Guidelines for the use of the C language in critical
systems.
PSoC 3
October 2004
PSoC 4
Production
PSoC 5LP
Production
PK51
9.51
GCC
4.7.3
RVDS
4.1
MDK
4.1
PSoC Creator
3.0 SP1
Target Device
Target Compiler
Generation Tool
PSoC® Creator™ System Reference Guide, Document Number: 001-94480, Rev. **
Production
109
MISRA Compliance
Component
Name
Version
MISRA Checking Tool
Programming Research QA C source code analyzer for Windows
8.1-R
Programming Research QA C MISRA-C:2004 Compliance Module
(M2CM)
3.2
The MISRA rules 1.5, 2.4, 3.3, and 5.7 are not enforced by Programming Research QA C. The
compliance with these rules was verified manually by code review.
Project Deviations
A Project Deviations are defined as a permitted relaxation of the MISRA rules requirements that are
applied for source code that is shipped with PSoC Creator. The list of deviated rules is provided in the
table below.
1
MISRA-C:
2004 Rule
Rule Class Rule Description
1
(R/A)
Description of Deviation(s)
1.1
R
This rule states that code shall conform
to C ISO/IEC 9899:1990 standard.
5.1
R
5.7
A
This rule says that both internal and
external identifiers shall not rely on the
significance of more than 31
characters.
Verify that no identifier name should is
reused.
Some C language extensions (like interrupt
keyword) relate to device hardware
functionality and cannot be practically
avoided.
In the main.c file that is generate by PSoC
Creator the non-standard main() declaration is
used: “void main()”. The standard declaration
is “int main()”
The number of macro definitions exceeds
1024 - program does not conform strictly to
ISO:C90.
The length of names based on user-defined
names depends on the length of the userdefine names.
8.7
R
Objects shall be defined at block scope
if they are only accessed from within a
single function.
8.10
R
11.3
A
All declarations and definitions of
objects or functions at file scope shall
have internal linkage unless external
linkage is required.
This rule states that cast should not be
performed between a pointer type and
an integral type.
Local variables with the same name may
appear in different functions. Aside from
commonly used names such as 'i', generated
API functions for multiple instances of the
same component will have identical local
variable names.
The object 'InstanceName_initVar' is only
referenced by function 'InstanceName_Start',
in the translation unit where it is defined. The
intention of this publicly available global
variable is to be used by user application.
Components API are designed to be used in
user application and might not be used in
component API.
The cast from unsigned int to pointer does not
have any unintended effect, as it is a
consequence of the definition of a structure
based on hardware registers.
Required / Advisory
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110
MISRA Compliance
MISRA-C:
2004 Rule
Rule Class Rule Description
1
(R/A)
Description of Deviation(s)
14.1
R
There shall be no unreachable code.
21.1
R
Minimization of run-time failures shall
be ensured by the use of at least one
of:
a) static analysis tools/techniques;
b) dynamic analysis tools/techniques;
c) explicit coding of checks to handle
run-time faults.
Some functions that are part of the component
API are not used within component API.
Components API are designed to be used in
user application and might not be used in
component API.
Some components in some specific
configurations can contain redundant
operations introduced because of generalized
implementation approach.
Documentation Related Rules
This section provides information on implementation-defined behavior of the toolchains supported by
PSoC Creator. The list of deviated rules is provided in the table below.
MISRA-C:
2004 Rule
Rule Class Rule Description
1
(R/A)
Description
1.3
R
Multiple compilers and/or languages
shall only be used if there is a
common defined interface standard for
object code to which the
languages/compilers/assemblers
conform.
1.4
R
1.5
A
3.1
R
The compiler/linker shall be checked
to ensure that 31 character
significance and case sensitivity are
supported for external identifiers.
Rule states that floating-point
implementation should comply with a
defined floating-point standard.
All usage of implementation-defined
behavior shall be documented.
No multiple compilers and languages can be
used at a time for PSoC Creator projects.
The PK51 linker produces OMF-51 object
module format. The GCC linker produces
EABI format files. The RVDS and MDK linkers
produce files of ARM ELF format.
PK51 and GCC treat more than 31 characters
of internal and external identifier length, and
are case sensitive (e.g., Id and ID are not
equal).
Floating-point arithmetic implementation
conforms to IEEE-754 standard.
3.2
R
The character set and the
corresponding encoding shall be
documented.
3.3
A
3.5
R
3.6
R
This rule states that implementation of
integer division should be
documented.
This rules requires implementation
defined behavior and packing of bit
fields be documented.
All libraries used in production code
shall be written to comply with the
provisions of this document, and shall
have been subject to appropriate
validation.
For the documentation on PK51 and GCC
compilers, refer to the Help menu,
Documentation sub-menu, Keil and GCC
commands respectively.
The Windows-1252 (CP-1252) character set
encoding is used.
Some characters that are used for source
code generation in PSoC Creator are not
included in character set, defined by ISO-IEC
9899-1900 "Programming languages — C".
When dividing two signed integers, one of
which is positive and one negative compiler
rounds up with a negative remainder.
The use of bit-fields is avoided.
The C standard libraries provided with C51,
GCC, and RVCT have not been reviewed for
compliance. Some code uses memset and
memcpy. The compiler may also insert calls to
its vendor-specific compiler support library.
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MISRA Compliance
PSoC Creator Generated Sources Deviations
This section provides the list of deviations that are applicable for the code that is generated by PSoC
Creator. The list of deviated rules is provided in the table below.
MISRA-C:
2004 Rule
Rule Class Rule Description
1
(R/A)
3.4
R
11.4
A
14.1
R
15.2
R
15.3
R
17.4
R
19.7
A
Description of Deviation(s)
All uses of the #pragma directive shall
be documented.
The #pragma directive is required to ensure
that the C51 compiler produces efficient code
for generated functions related to the
AMuxSeq component.
This rule states that cast should not be CYMEMZERO8 and CYCONFIGCPY8 use
performed between a pointer to object void * arguments for compatibility with
type and a different pointer to object
memset/memcpy but must use a pointer to an
type.
actual type internally.
Rule requires that there shall be no
The CYMEMZERO, CYMEMZERO8,
unreachable code.
CYCONFIGCPY, CYCONFIGCPY8,
CYCONFIGCPYCODE, and
CYCONFIGCPYCODE8 are often but not
always used.
Switch cases must end with break
The code structure is required to ensure that
statements.
the C51 compiler produces efficient code for
generated functions related to the AMuxSeq
component.
default must be the last clause in a
The code structure is required to ensure that
switch statement.
the C51 compiler produces efficient code for
generated functions related to the AMuxSeq
component.
Array indexing shall be only allowed
The CYMEMZERO8 and CYCONFIGCPY8
form of pointer arithmetic.
have void * arguments for compatibility with
memset/memcpy.
The rule says that function shall be
The CYMEMZERO, CYMEMZERO8,
used instead of function-like macro.
CYCONFIGCPY, CYCONFIGCPY8,
CYCONFIGCPYCODE, and
CYCONFIGCPYCODE8 macros are used to
call cymemzero, cyconfigcpy, and
cyconfigcpycode in a device-independent way.
The macros cannot be converted to functions
without significantly increasing the time and
memory required for each function call (this is
a limitation of C51). The macros have been
converted to functions for GCC/RVCT.
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MISRA Compliance
cy_boot Component-Specific Deviations
This section provides the list of cy_boot component specific-deviations. The list of deviated rules is
provided in the table below.
MISRA-C:
2004 Rule
Rule Class
1
(R/A)
Rule Description
6.3
A
typedefs that indicate size and
signedness should be used in place of
the basic types.
8.7
R
8.12
R
12.10
R
12.13
A
13.2
A
13.5
R
8.8
R
10.1
R
10.3
R
14.3
R
11.4
A
Description of Deviation(s)
For PSoC 4/PSoC 5LP, the RealView C
Library initialization function __main(void) in
startup file (Cm0Start.c/Cm3Start.c) file
returns value of basic type 'int'.
Objects shall be defined at block
For PSoC 4/PSoC 5LP, the
scope if they are only accessed from
cySysNoInitDataValid variable is intentionally
within a single function.
declared as global in Cm0Start.c/Cm3Start.c
files to prevent linker from CY_NOINIT section
removal.
When an array is declared with
For PSoC 4/PSoC 5LP
external linkage, its size shall be
(Cm0Start.c/Cm3Start.c), the __cy_regions
stated explicitly or defined implicitly by array of structures is declared with unknown
initialization.
size.
The comma operator shall not be
The Cm0Start.c/Cm3Start.c files, contain the
used.
complex for() statement that performs sections
The increment (++) and decrement (--) initialization and has the mentioned
deviations.
operators should not be mixed with
other operators in an expression.
Tests of a value against zero should
be made explicit, unless the operand
is effectively Boolean.
The three expressions of a for
statement shall be concerned only
with loop control.
An external object or function shall be For the PSoC 4/PSoC 5LP, some objects is
declared in one and only one file.
being declared with external linkage in
Cm3Start.c/Cm3Start.c file and this
declaration is not in a header file.
The value of an expression of integer
PSoC 4/ PSoC 5LP: CMSIS Core: An integer
type shall not be implicitly converted to constant of 'essentially unsigned' type is being
a different underlying type under some converted to signed type on assignment in
circumstances.
CMSIS Core hardware abstraction layer.
The value of a complex expression of The DMA API has a composite expression of
integer type may only be cast to a type 'essentially unsigned' type (unsigned char) is
that is narrower and of the same
being cast to a wider unsigned type, 'unsigned
signedness as the underlying type of
long'. This deviation is not present for PSoC 4
the expression.
cy_boot code.
Before preprocessing, a null statement The CYASSERT() macro has null statement is
shall only occur on a line by itself; it
located close to other code.
may be followed by a comment
provided that the first character
following the null statement is a whitespace character.
A cast should not be performed
The DMA and Interrupt API use casts between
between a pointer to object type and a a pointer to object type and a different pointer
different pointer to object type.
to object type.
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MISRA Compliance
MISRA-C:
2004 Rule
Rule Class
1
(R/A)
11.5
14.7
R
17.4
R
19.4
R
19.7
A
Rule Description
Description of Deviation(s)
A cast shall not be performed that
removes any const or volatile
qualification from the type addressed
by a pointer.
A function shall have a single point of
exit at the end of the function.
The volatile qualification is lost during pointer
cast to pointer to void before passing to the
memcpy() function.
The CyPmSleep() and CyPmHibernate()
functions has complex conditional structure
and one more `return` path is added for PSoC
3/PSoC 5LP to return immediately if device is
not ready for low power mode entry. This
deviation is not present for PSoC 4 cy_boot
code.
Array indexing shall be the only
The DMA, Flash and Interrupt APIs use array
allowed form of pointer arithmetic.
indexing that are applied to an object of
pointer type to access hardware registers,
buffer allocated by user and vector tables
correspondingly.
C macros shall only expand to a
The CYASSERT(),
braced initializer, a constant, a
INTERRUPT_DISABLE_IRQ,
parenthesized expression, a type
INTERRUPT_ENABLE_IRQ,
qualifier, a storage class specifier, or a CyGlobalIntEnable, and CyGlobalIntDisable
do-while-zero construct.
macro defines a braced code statement block.
A function should be used in
Deviated since function-like macros are used
preference to a function-like macro.
to allow more efficient code.
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15 cy_boot Component Changes
Version 4.11
This section lists and describes the major changes in the cy_boot component version 4.11:
Description of Version 4.11 Changes
Reason for Changes / Impact
The CySysFlashWriteRow() function now checks
the data to be written and, if necessary, modifies it
to have a non-zero checksum. After writing to Flash,
the modified data is replaced (Flash program) with
the correct (original) data.
Cypress identified a defect with the Flash write
functionality of the PSoC 4000, PSoC 4100, and
PSoC 4200 devices. The CySysFlashWriteRow()
function in the cy_boot [v4.0 and v4.10]
component fails to write a row of flash memory if
the data to be written has a zero in the lower 32bits of the checksum.
Version 4.10
This section lists and describes the major changes in the cy_boot component version 4.10:
Description of Version 4.10 Changes
Reason for Changes / Impact
PSoC 4: Added CySysGetResetReason() function.
Reports the cause for the latest reset(s) that
occurred in the system.
New device support.
Added support for the PSoC 4000 family.
PSoC 3: Added reentrancy support for the
CySpcLock() and CySpcUnlock() functions.
PSoC 3/ PSoC 5LP: Fixed the defect in
CyPmRestoreClocks() function, that can might to
the device halt during the function execution, in
some clock system configurations, when PLL is
not sourced by IMO and IMO is manually stopped
by user code.
PSoC 4: Added note that enabling or disabling a
WDT requires three LFCLK cycles to come into
effect, during that period the SYSCLK should be
available.
PSoC 4: Added note that, after waking from Deep
Sleep, the WDT internal timer value is set to zero
until the ILO loads the register with the correct
value.
The device should not put into Deep Sleep mode
during that period.
This led to an increase in low-power mode current
consumption.
The work around is to wait for the first positive
edge of the ILO clock before allowing the
WDT_CTR_* registers to be read by
CySysWdtReadCount() function.
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cy_boot Component Changes
Description of Version 4.10 Changes
Reason for Changes / Impact
Added note to the Working with Flash and
EEPROM section with the information that CPU
code execution can be halted till the flash write is
complete.
Added note to the Working with Flash and
EEPROM section with the information that power
manager will not put the device into a low power
state if the system performance controller (SPC) is
executing a command.
PSoC 3 / PSoC 5LP: The CyPmRestoreClocks()
implementation was enhanced by polling status and
proceed as soon as PLL is locked. Added merge
section to add ability of handling cases when
predefined timeout is not enough.
PSoC 4: Fixed a defect in CySysWdtClearInterrupt()
that caused unintentional clearing of the WDT
interrupt status bit.
Version 4.0
This section lists and describes the major changes in the cy_boot component version 4.0:
Description of Version 4.0 Changes
Added note to the Flash and EEPROM section
about unavailability of the Store Configuration Data
in ECC Memory DWR option for the bootloader
project type.
Added note to the Working with Flash and
EEPROM section that when writing Flash, data in
the instruction cache can become stale.
Fixed issue in the CyDmaChEnable() and
CyDmaChDisable() functions.
Removed references to PSoC 5 device.
PSoC Creator Generated Sources Deviations
section was updated with the MISRA deviations
related to the AMuxSeq component.
The CY_IMO_FREQ_74MHZ parameter was added
to the CyIMO_SetFreq() function.
PSoC 4: Added CyExitCriticalSection() function call
after WFI instruction in the CySysPmHibernate()
function.
Reason for Changes / Impact
Call CyFlushCache() to invalidate the data in
cache and force fresh information to be loaded
from Flash.
If DMA request occurred during these functions,
the DMA channels configuration could be
corrupted. The APIs were changed to address
this problem.
PSoC 5 has been replaced by PSoC 5LP.
Support of the 80 MHZ PSoC 5LP devices.
If any interrupt occurred between
CyEnterCriticalSection() and WFI instruction
execution, the device could skip low power mode
entry request and continue code execution with
global interrupts disabled.
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cy_boot Component Changes
Version 3.40 and Older
Version 3.40
This section lists and describes the major changes in the cy_boot component version 3.40:
Description of Version 3.40 Changes
Reason for Changes / Impact
Added PSoC 4 device support.
PSoC 3: Updated CyPmSleep() function description
with the information that hardware buzz must be
disabled before sleep mode entry.
New device support.
Using hardware buzz in conjunction with other
device wakeup sources can cause the device to
lockup, halting further code execution. Refer to
the device errata for more information.
As hardware buzz is required for LVI, HVI, and
Brown Out detect operations – they must be
disabled before sleep mode entry and restored on
wakeup. If LVI or HVI is enabled, CyPmSleep() will
halt device if project is compiled in debug mode.
Version 3.30
This section lists and describes the major changes in the cy_boot component version 3.30:
Description of Version 3.30 Changes
Updates to support PSoC Creator 2.2.
Added MISRA Compliance section.
Added Low Voltage Analog Boost Clocks section.
Added requirement about interrupt configuration,
when interrupt is sources from PICU and used as a
wakeup event.
The delay between Bus clock and analog clocks
configuration save/restore moved from
CyPmSleep() and CyPmHibernate() functions to
CyPmSaveClocks() / CyPmRestoreClocks().
Reason for Changes / Impact
New feature for the SC-based (TIA, Mixer, PGA
and PGA_Inv) components.
For PSoC 5LP, the interrupt component
connected to the wakeup source may not use the
"RISING_EDGE" detect option. Use the "LEVEL"
option instead.
This modification decrease CyPmSleep() and
CyPmHibernate() functions execution time.
The components that use analog clock must not
be used after CyPmSaveClocks() execution till
the clocks configuration will be restored by
CyPmRestoreClocks().
Added float32 and float64 data types. The type
float64 is not available for PSoC 3 devices.
Version 3.20
This section lists and describes the major changes in the cy_boot component version 3.20:
Description of Version 3.20 Changes
Reason for Changes / Impact
Many minor edits throughout the document to
distinguish features of PSoC 5 and PSoC 5LP
devices.
The PSoC 5LP Alternate Active usage model was
changed to be same as for PSoC 5.
Improve PSoC 5 and PSoC 5LP documentation.
No parameters are used for CyPmAltAct(). That
means NONE should be passed for the
parameters. The device will go into Alternate
Active mode until an enabled interrupt occurs.
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cy_boot Component Changes
Description of Version 3.20 Changes
Reason for Changes / Impact
The interface of the CyIMO_SetFreq() function was
updated for PSoC 5LP to support 62 and 72 MHz
frequencies.
Added interface to configure IMO to 62 and 72
MHz on PSoC 5LP.
Version 3.10
This section lists and describes the major changes in the cy_boot component version 3.10:
Description of Version 3.10 Changes
Reason for Changes / Impact
The Bootloader system was redesigned in cy_boot
version 3.0 to separate the Bootloader and
Bootloadable components. The change is listed
here as well for migrating from older versions.
A few edits were applied to the Voltage Detect
APIs: fixed a typo in the register definition, added
CyVdLvDigitEnable() function threshold parameter
mask to protect from invalid parameter values,
updated CyVdLvDigitEnable() and
CyVdLvAnalogEnable() functions to use delay
instead of while loop during hardware initialization.
Minor updates to the CyPmSleep() function.
See Bootloader Migration on page 77 for more
information.
To improve the overall implementation of these
APIs.
Better support of latest PSoC 3 devices.
Version 3.0
This section lists and describes the major changes in the cy_boot component version 3.0:
Description of Version 3.0 Changes
Reason for Changes / Impact
The Bootloader system was redesigned to separate
the Bootloader and Bootloadable components.
The CyPmSleep() function implementation was
updated to preserve/restore PRES state
before/after Sleep mode. The support of the
HVI/LVI functionality added.
Added following Voltage Detect APIs:
CyVdLvDigitEnable(),CyVdLvAnalogEnable(),CyVd
LvDigitDisable(),CyVdLvAnalogDisable(),CyVdHvA
nalogEnable(),CyVdHvAnalogDisable(),CyVdSticky
Status() and CyVdRealTimeStatus().
The implementation of the Flash API was slightly
modified as the SPC API used in Flash APIs was
refactored.
The implementation of the CyXTAL_32KHZ_Start(),
CyXTAL_32KHZ_Stop(),
CyXTAL_32KHZ_ReadStatus() and
CyXTAL_32KHZ_SetPowerMode() APIs was
updated.
The implementation of the CyXTAL_Start() function
for PSoC 5 parts was changed. For more
information on function see Clocking section.
See Bootloader Migration on page 77 for more
information.
New functionality support.
Added voltage monitoring APIs.
The implementation quality improvements.
Added additional timeouts to ensure proper block
start-up.
Changes were made to make sure that MHZ
XTAL starts successfully on PSoC 5 parts.
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cy_boot Component Changes
Description of Version 3.0 Changes
Reason for Changes / Impact
The following APIs were removed for PSoC 5 parts:
CyXTAL_ReadStatus(),
CyXTAL_EnableErrStatus(),
CyXTAL_DisableErrStatus(),
CyXTAL_EnableFaultRecovery(),
CyXTAL_DisableFaultRecovery().
The CyDmacConfigure() function is now called by
the startup code only if DMA component is placed
onto design schematic.
The functionality provided within these APIs is not
supported by the PSoC 5 part.
The CyXTAL_32KHZ_ReadStatus() function
implementation was changed by removing digital
measurement status return.
Updated description of following APIs:
CyFlash_SetWaitCycles().
The address of the top of reentrant stack was
decremented from CYDEV_SRAM_SIZE to
(CYDEV_SRAM_SIZE - 3) for PSoC 3.
The CyIMO_SetFreq() function implementation was
updated by removing support of 74 and 62 MHz
parameters for PSoC 5 parts.
The minimal P divider value for the
CyPLL_OUT_SetPQ() was risen from 4 up to 8.
The CyXTAL_SetFbVoltage()/SetWdVoltage() were
added for PSoC 5LP devices.
The description of the CyWdtStart() was updated.
Increase device startup time in case if DMA is not
used within design. The CyDmacConfigure()
function should be called manually if DMA
functionality is used without DMA component.
The analog status measurement is the only
reliable source.
Changes were made to improve power mode
configuration.
Prevent rewriting CyResetStatus variable with the
parameters and/or local variables of the reentrant
function during its execution.
Removal of the functionality that is not supported
by device.
To meet hardware requirements
The functionality provided by these APIs is
available in PSoC 5LP.
Added notes on WDT operation during low power
modes for PSoC 5.
The implementation of the CyPmSleep() for PSoC 5 Not putting CTW in reset state on wakeup allows
to combine CTW usage in both Active and low
was changed not to hold CTW in reset on wakeup.
power modes for PSoC 5.
The Preservation of Reset Status section was
The software reset behavior of other resets is
explained. Explained how the reset status
updated with more detailed information.
variable can be used.
Updated description of following APIs:
To reflect implementation better.
CyMasterClk_SetDivider(),CyWdtStart(),CyWdtStart
().
The Startup and Linking section was updated. The
To provide more information on device operation.
information on using custom linker script was
added.
Following macros were removed: CYWDT_TICKS
The CyWdtStart() and CyWdtClear() should be
CYWDT_CLEAR, CYWDT_ENABLE
used instead.
CYWDT_DISABLE_AUTO_FEED.
The CyCpuClk_SetDivider() was removed for PSoC The hardware does not support this functionality.
5 devices.
The cystrcpy(), cystrlen(), CyGetSwapReg16() and The library functions should be used.
CySetSwapReg16() APIs were removed.
The return value description for
Function returns 0 if interrupts were previously
CyEnterCriticalSection() function was updated for
enabled or 1 if interrupts were previously
PSoC 5.
disabled.
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cy_boot Component Changes
Description of Version 3.0 Changes
Reason for Changes / Impact
Added all APIs with the CYREENTRANT keyword
when they are included in the .cyre file.
Not all APIs are truly reentrant. Comments in the
component API source files indicate which
functions are candidates.
This change is required to eliminate compiler
warnings for functions that are not reentrant used
in a safe way: protected from concurrent calls by
flags or Critical Sections.
Added PSoC 5LP support
Version 2.40 and Older
Version 2.40
This section lists and describes the major changes in the cy_boot component version 2.40:
Description of Version 2.40 Changes
Reason for Changes / Impact
Updated the CyPmSleep() and CyPmHibernate()
APIs.
Changes were made to improve power mode
configuration.
Version 2.30
This section lists and describes the major changes in the cy_boot component version 2.30:
Description of Version 2.30 Changes
Reason for Changes / Impact
CyIntEnable and CyIntDisable functions have been
changed to be CYREENTRANT by default.
Many components require CyIntEnable and
CyIntDisable to be reentrant and these
components have no way to cause that to
happen. This means you no longer need to
populate a cyre file for these functions that you do
not call.
User was made responsible for clock power
modes configuration during Sleep and Alternate
Active mode.
The implementation of CyPmSleep() and
CyPmAltActive() functions were modified by
removing 32 KHz ECO,100 KHz and 1 KHz ILO
power mode configuration before device low power
mode entry.
The implementation of the CyPmSaveClocks() was
updated to set IMO clock frequency to 48 MHz
when "Enable Fast IMO during startup" is enabled,
and to 12 MHz otherwise. The IMO frequency is
always set to 12 MHz just before the low power
mode entry and restored immediately after wakeup.
The CyPmRestoreClocks() restores original value of
the IMO clock.
The CyILO_SetPowerMode() and
CyXTAL_32KHZ_SetPowerMode() can be used
to configure clock power modes.
The information regarding user responsibility of
clock power mode configuration was added at the
PM API section.
The IMO value should match FIMO and FIMO is
always 12 MHz.
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cy_boot Component Changes
Description of Version 2.30 Changes
Reason for Changes / Impact
The implementation of the CyPmRestoreClocks()
function was updated by removing restoring MHz
ECO and PLL disabled state.
Global interrupts are disabled on
CyPmSleep()/CyPmHibernate() entry and restored
before return from the function.
The CyPmSleep() and CyPmAltAct() function
implementations for PSoC 5 devices were updated
to ignore all parameters. The PSoC 5 device will go
into Sleep mode until it is woken by an interrupt
from one of three wakeup sources: CTW, Once per
second, or Port Interrupt Controller (PICU). These
wakeup sources must already be configured to
generate an interrupt. The CTW is configured using
the Sleep Timer component and the Once per
second interrupt using the Real Time Clock
component.
Updated architecture- and silicon-specific #defines
to be used across the content.
Improved performance of non-DMA configuration on
8051 devices.
The CyPmRestoreClocks() function is expected to
be called only after CyPmSaveClocks(), while the
last one always disables MHz ECO and PLL.
Interrupts are disabled to prevent their occurrence
before the state of the device has been restored.
The implementation of the CyPmRestoreClocks()
was updated for PSoC 5 silicon. The megahertz
crystal is given 130 ms to stabilize. Its readiness is
not verified after the hold-off timeout.
The power mode of the source clocks for the timer
used as the wakeup timer was removed from PM
API functions.
PSoC Creator Power Management section was
updated.
The CyPmSleep() and CyPmAltAct() functions
have to be used only with the following
parameters:
CyPmSleep(PM_SLEEP_TIME_NONE,
PM_SLEEP_SRC_NONE) and
CyPmAltAct(PM_ALT_ACT_TIME_NONE,
PM_ALT_ACT_SRC_NONE).
These modifications decrease the startup time
and slightly reduce consumption of code memory
and internal data memory.
These modifications increase crystal startup time,
but ensure that crystal is ready to be used.
Before calling PM API function, you must
manually configure the power mode of the source
clocks for the timer that will be used as the
wakeup timer.
More detailed information on Power Management
API usage was added.
Version 2.21
This section lists and describes the major changes in the cy_boot component version 2.21:
Description of Version 2.21 Changes
Reason for Changes / Impact
Provide a new option for selecting how to
compute checksums on data transferred
from the bootloader host to the
bootloader.
Provide a generic option to allow users to
define their own custom bootloader
communication functions.
Provide a more robust way to check for errors during IO
transfers.
Updated a few Power Management
functions to prevent some possible
issues.
Make adding support for additional communication
protocols (SPI, UART, ...) easier. Also provides a means of
supporting multiple communications components
concurrently in the same design.
Some parentheses were missing which could cause items
to be evaluated in the wrong order.
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cy_boot Component Changes
Description of Version 2.21 Changes
Reason for Changes / Impact
Added a variable CyResetStatus that can
be used to get the information from the
RESET_SR0 register.
This is provided because many of the fields contained within
the RESET_SR0 register are clear-on-read. Since the
bootloader needs to access this register as part of its
operation, it prevents the actual application code from
accessing the values. The variable is provided so that the
application can still get access to all the information.
On some PSoC 3 devices the NVL information may not be
initialized properly. This workaround is provided to ensure
that the NVLs are properly loaded before performing any of
the startup code.
Added a workaround for some PSoC 3
devices to ensure that the NVL values
have been properly initialized.
Version 2.20
Version 2.20 and older are obsolete.
PSoC® Creator™ System Reference Guide, Document Number: 001-94480, Rev. **
122
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