PSoC 6 Peripheral Driver Library
SysLib (System Library)

General Description

The system libraries provide APIs that can be called in the user application to handle the timing, logical checking or register.

The functions and other declarations used in this driver are in cy_syslib.h. You can include cy_pdl.h to get access to all functions and declarations in the PDL.

The SysLib driver contains a set of different system functions. These functions can be called in the application routine. Major features of the system library:

Configuration Considerations

Assertion Usage
Use the CY_ASSERT() macro to check expressions that must be true if the program is running correctly. It is a convenient way to insert sanity checks. The CY_ASSERT() macro is defined in the cy_utils.h file, which is part of the Cypress Core Library (core-lib). The macro behavior is as follows: if the expression passed to the macro is false, the CPU is halted.
The PDL source code uses this assert mechanism extensively. It is recommended that you enable asserts when debugging firmware.
Assertion Classes and Levels
The Cypress Core Library defines three assert classes, which correspond to different kinds of parameters. There is a corresponding assert "level" for each class.

Class MacroLevel MacroType of check
CY_ASSERT_CLASS_1 CY_ASSERT_L1 A parameter that could change between different PSoC devices (e.g. the number of clock paths)
CY_ASSERT_CLASS_2 CY_ASSERT_L2 A parameter that has fixed limits such as a counter period
CY_ASSERT_CLASS_3 CY_ASSERT_L3 A parameter that is an enum constant

Firmware defines which ASSERT class is enabled by defining CY_ASSERT_LEVEL. This is a compiler command line argument, similar to how the DEBUG / NDEBUG macro is passed.
Enabling any class also enables any lower-numbered class. CY_ASSERT_CLASS_3 is the default level, and it enables asserts for all three classes. The following example shows the command-line option to enable all the assert levels:

The use of special characters, such as spaces, parenthesis, etc. must be protected with quotes.

After CY_ASSERT_LEVEL is defined, firmware can use one of the three level macros to make an assertion. For example, if the parameter can vary between devices, firmware uses the L1 macro.


If the parameter has bounds, firmware uses L2.


If the parameter is an enum, firmware uses L3.


Each check uses the appropriate level macro for the kind of parameter being checked. If a particular assert class/level is not enabled, then the assert does nothing.

More Information

Refer to the technical reference manual (TRM).

MISRA-C Compliance

MISRA Rule Rule Class (Required/Advisory) Rule Description Description of Deviation(s)
2.1 R This function contains a mixture of in-line assembler statements and C statements. This si required by design of the Cy_SysLib_Halt function.
18.4 R Unions shall not be used. The unions are used for CFSR, HFSR and SHCSR Fault Status Registers content access as a word in code and as a structure during debug.

Known Issues

The function malloc() does not return an error when the allocation size is bigger than the heap size. PDL does not implement the _sbrk function. The user needs to add custom _sbrk function.


VersionChangesReason for Change
2.60.1 Updated the Configuration Considerations section with the information that CY_ASSERT() macro is defined in the cy_utils.h file, which is part of the Cypress Core Library (core-lib) Documentation update and clarification.
2.60 Updated the following functions for the PSoC 64 devices: Cy_SysLib_ClearFlashCacheAndBuffer, Cy_SysLib_ClearResetReason, Cy_SysLib_SetWaitStates. Added PSoC 64 device support.
Minor documentation updates. Documentation enhancement.
2.50.3 Add section Known Issues Documentation update and clarification.
2.50.1 Used the core library defines for the message codes forming. Improve PDL code base.
2.40.1 Correct the CY_RAMFUNC_BEGIN macro for the IAR compiler. Removed the IAR compiler warning.
2.40 Added new macros CY_SYSLIB_DIV_ROUND and CY_SYSLIB_DIV_ROUNDUP to easy perform integer division with rounding. Improve PDL code base.
2.30 Updated implementation of the Cy_SysLib_AsmInfiniteLoop() function to be compatible with ARMC6. Provided support for the ARM Compiler 6.
Minor documentation edits. Documentation update and clarification.
Added new macros CY_RAMFUNC_BEGIN and CY_RAMFUNC_END for convenient placement function in RAM for all supported compilers. Improve user experience.
2.20 Updated implementation of the Cy_SysLib_AssertFailed() function to be available in Release and Debug modes. Provided support for the PDL static library in Release mode.
Minor documentation edits. Documentation update and clarification.
2.10 Flattened the organization of the driver source code into the single source directory and the single include directory. Driver library directory-structure simplification.
Added the following macros: CY_REG32_CLR_SET, _CLR_SET_FLD16U, CY_REG16_CLR_SET, _CLR_SET_FLD8U, CY_REG8_CLR_SET Register access simplification.
Removed the Cy_SysLib_GetNumHfclkResetCause API function. This feature is not supported by SRSS_ver1.
Added register access layer. Use register access macros instead of direct register access using dereferenced pointers. Makes register access device-independent, so that the PDL does not need to be recompiled for each supported part number.
2.0.1 Minor documentation edits Documentation update and clarification
2.0 Added Cy_SysLib_ResetBackupDomain() API implementation.
Added CY_NOINLINE attribute implementation.
Added DIE_YEAR field to 64-bit unique ID return value of Cy_SysLib_GetUniqueId() API.
Added storing of SCB->HFSR, SCB->SHCSR registers and SCB->MMFAR, SCB->BFAR addresses to Fault Handler debug structure.
Optimized Cy_SysLib_SetWaitStates() API implementation.
Improvements made based on usability feedback.
Added Assertion Classes and Levels. For error checking, parameter validation and status returns in the PDL API.
Applied CY_NOINIT attribute to cy_assertFileName, cy_assertLine, and cy_faultFrame global variables. To store debug information into a non-zero init area for future analysis.
Removed CY_WEAK attribute implementation. CMSIS __WEAK attribute should be used instead.
1.0 Initial version

API Reference

 Data Structures
 Enumerated Types