Class B Library Interface

Table of contents

1. Constants Summary
2. Data types Summary
3. Interface Routines Summary
4. Constants
   1. CLASSB_RESULT_ADDR
   2. CLASSB_COMPL_RESULT_ADDR
   3. CLASSB_ONGOING_TEST_VAR_ADDR
   4. CLASSB_TEST_IN_PROG_VAR_ADDR
   5. CLASSB_WDT_TEST_IN_PROG_VAR_ADDR
   6. CLASSB_FLASH_TEST_VAR_ADDR
   7. CLASSB_INTERRUPT_TEST_VAR_ADDR
   8. CLASSB_INTERRUPT_COUNT_VAR_ADDR
   9. CLASSB_SRAM_STARTUP_TEST_SIZE
   10. CLASSB_CLOCK_ERROR_PERCENT
   11. CLASSB_CLOCK_RTC_CLK_FREQ
   12. CLASSB_CLOCK_TEST_RTC_CYCLES
   13. CLASSB_CLOCK_TEST_RTC_RATIO_NS
   14. CLASSB_CLOCK_TEST_RATIO_NS_MS
   15. CLASSB_CLOCK_DEFAULT_CLOCK_FREQ
   16. CLASSB_INVALID_TEST_ID
   17. CLASSB_CLOCK_MAX_CLOCK_FREQ
   18. CLASSB_CLOCK_MAX_SYSTICK_VAL
   19. CLASSB_CLOCK_MAX_TEST_ACCURACY
   20. CLASSB_CLOCK_MUL_FACTOR
   21. CLASSB_FLASH_CRC32_POLYNOMIAL
   22. CLASSB_SRAM_TEST_BUFFER_SIZE
   23. CLASSB_SRAM_APP_AREA_START
   24. CLASSB_SRAM_FINAL_WORD_ADDRESS
   25. CLASSB_SRAM_BUFF_START_ADDRESS
   26. CLASSB_SRAM_TEMP_STACK_ADDRESS
   27. CLASSB_SRAM_ALL_32BITS_HIGH
   28. CLASSB_INTR_DEVICE_VECT_OFFSET
   29. CLASSB_INTR_VECTOR_TABLE_SIZE
   30. CLASSB_INTR_MAX_INT_COUNT
   31. CLASSB_INTR_TEST_RTC_COUNT
   32. CLASSB_INTR_TEST_TC_COUNT
5. Data types
   1. CLASSB_TEST_ID
   2. CLASSB_TEST_STATUS
   3. CLASSB_TEST_STATE
   4. CLASSB_INIT_STATUS
   5. CLASSB_STARTUP_STATUS
   6. CLASSB_TEST_TYPE
   7. *CLASSB_SST_RESULT_BF
   8. *CLASSB_RST_RESULT_BF
   9. CLASSB_SRAM_MARCH_ALGO
   10. CLASSB_PORT_INDEX
   11. CLASSB_PORT_PIN
   12. CLASSB_PORT_PIN_STATE
   13. CLASSB_CPU_PC_TEST_VALUES
6. Interface Routines
   1. CLASSB_ClearTestResults
   2. CLASSB_GetTestResult
   3. CLASSB_TestWDT
   4. CLASSB_GlobalsInit
   5. CLASSB_Init
   6. CLASSB_Startup_Tests
   7. CLASSB_SST_WDT_Recovery
   8. CLASSB_App_WDT_Recovery
   9. CLASSB_SelfTest_FailSafe
   10. CLASSB_CPU_RegistersTest
   11. CLASSB_FPU_RegistersTest
   12. CLASSB_CPU_PCTest
   13. CLASSB_FlashCRCGenerate
   14. CLASSB_FlashCRCTest
   15. CLASSB_SRAM_MarchTestInit
   16. CLASSB_ClockTest
   17. CLASSB_SST_InterruptTest
   18. CLASSB_RST_IOTest
   19. CLASSB_IO_InputSamplingEnable

Constants Summary

Data types Summary

Interface Routines Summary

Constants

CLASSB_RESULT_ADDR

Summary

Address of test results.

Description

This constant defines the address in SRAM where the test results are stored.

Remarks

This value must not be modified.

#define CLASSB_RESULT_ADDR (0x20000000U)

CLASSB_COMPL_RESULT_ADDR

Summary

Address of one’s complement test results.

Description

This constant defines the address in SRAM where the one’s complement of the test results are stored.

Remarks

This value must not be modified.

#define CLASSB_COMPL_RESULT_ADDR (0x20000004U)

CLASSB_ONGOING_TEST_VAR_ADDR

Summary

Address at which the ID of ongoing test is stored.

Description

This constant defines the address in SRAM where the the ID of ongoing test is stored.

Remarks

This value must not be modified.

#define CLASSB_ONGOING_TEST_VAR_ADDR (0x20000008U)

CLASSB_TEST_IN_PROG_VAR_ADDR

Summary

Address of the variable which indicates that a Class B test is in progress.

Description

Defines the address of the variable which indicates that a Class B test is in progress.

Remarks

This value must not be modified.

#define CLASSB_TEST_IN_PROG_VAR_ADDR (0x2000000CU)

CLASSB_WDT_TEST_IN_PROG_VAR_ADDR

Summary

Address of the variable which indicates that a WDT test is in progress.

Description

Defines the address of the variable which indicates that a WDT test is in progress.

Remarks

This value must not be modified.

#define CLASSB_WDT_TEST_IN_PROG_VAR_ADDR (0x20000010U)

CLASSB_FLASH_TEST_VAR_ADDR

Summary

Address of the variable which indicates that a flash test is in progress.

Description

Defines the address of the variable which indicates that a flash test is in progress.

Remarks

This value must not be modified.

#define CLASSB_FLASH_TEST_VAR_ADDR (0x20000014U)

CLASSB_INTERRUPT_TEST_VAR_ADDR

Summary

Address of the variable which keeps interrupt test internal status.

Description

Defines the address of the variable which keeps interrupt test internal status.

Remarks

This value must not be modified.

#define CLASSB_INTERRUPT_TEST_VAR_ADDR (0x20000018U)

CLASSB_INTERRUPT_COUNT_VAR_ADDR

Summary

Address of the variable which keeps interrupt count.

Description

Defines the address of the variable which keeps interrupt count.

Remarks

This value must not be modified.

#define CLASSB_INTERRUPT_COUNT_VAR_ADDR (0x2000001cU)

CLASSB_SRAM_STARTUP_TEST_SIZE

Summary

Size of the SRAM tested during startup.

Description

Defines the size of the SRAM tested during startup. Modify this macro to change the area of the tested SRAM area. The test size must be a multiple of four.

Remarks

This value can be modified.

#define CLASSB_SRAM_STARTUP_TEST_SIZE (65536U)

CLASSB_CLOCK_ERROR_PERCENT

Summary

Clock error percentage selected for startup test.

Description

Defines the acceptable error percentage of the CPU clock. This value is configured via MHC and is used during startup self-test of the CPU clock.

Remarks

This value must not be modified.

#define CLASSB_CLOCK_ERROR_PERCENT (5U)

CLASSB_CLOCK_RTC_CLK_FREQ

Summary

RTC clock frequency.

Description

Defines the RTC clock frequency.

Remarks

This value must not be modified.

#define CLASSB_CLOCK_RTC_CLK_FREQ (32768U)

CLASSB_CLOCK_TEST_RTC_CYCLES

Summary

Duration of the CPU clock test.

Description

Defines the duration of the CPU clock test in terms of RTC cycles.

Remarks

This value must not be modified.

#define CLASSB_CLOCK_TEST_RTC_CYCLES (200U)

CLASSB_CLOCK_TEST_RTC_RATIO_NS

Summary

Duration of RTC clock in nano seconds.

Description

Defines the duration of RTC clock in nano seconds. This is used to calculate the duration of CPU clock test in terms of RTC cycles.

Remarks

RTC is clocked from 32768 Hz Crystal. One RTC cycle is 30517 nano sec. This value must not be modified.

#define CLASSB_CLOCK_TEST_RTC_RATIO_NS (30517U)

CLASSB_CLOCK_TEST_RATIO_NS_MS

Summary

Ratio of milli second to nano second.

Description

Defines the ratio of milli second to nano second. This is used to calculate the duration of CPU clock test in terms of RTC cycles.

Remarks

Used to avoid the use of floating point math. This value must not be modified.

#define CLASSB_CLOCK_TEST_RATIO_NS_MS (1000000U)

CLASSB_CLOCK_DEFAULT_CLOCK_FREQ

Summary

Default CPU clock speed.

Description

Defines the default CPU clock speed after a reset.

Remarks

This value must not be modified.

#define CLASSB_CLOCK_DEFAULT_CLOCK_FREQ (48000000U)

CLASSB_INVALID_TEST_ID

Summary

Invalid test ID.

Description

Defines a constant to initialize the variable which holds the ID of the ongoing self-test.

Remarks

This value must not be modified.

#define CLASSB_INVALID_TEST_ID (0xFFU)

CLASSB_CLOCK_MAX_CLOCK_FREQ

Summary

Maximum CPU clock speed.

Description

Defines the maximum CPU clock speed for the microcontroller.

Remarks

This value must not be modified.

#define CLASSB_CLOCK_MAX_CLOCK_FREQ (120000000U)

CLASSB_CLOCK_MAX_SYSTICK_VAL

Summary

Upper limit of SysTick counter.

Description

Defines the upper limit of SysTick counter.

Remarks

This value must not be modified.

#define CLASSB_CLOCK_MAX_SYSTICK_VAL (0xffffffU)

CLASSB_CLOCK_MAX_TEST_ACCURACY

Summary

Maximum detectable accuracy for clock self-test.

Description

Defines the maximum detectable accuracy for clock self-test.

Remarks

This value must not be modified.

#define CLASSB_CLOCK_MAX_TEST_ACCURACY (5U)

CLASSB_CLOCK_MUL_FACTOR

Summary

Multiplication factor used in clock test.

Description

Defines the multiplication factor used in clock test. This is used to calculate the CPU clock error. Used to avoid the use of floating point math.

Remarks

This value must not be modified.

#define CLASSB_CLOCK_MUL_FACTOR (128U)

CLASSB_FLASH_CRC32_POLYNOMIAL

Summary

CRC-32 polynomial.

Description

Defines the CRC-32 polynomial used for Flash self-test.

Remarks

This value must not be modified.

#define CLASSB_FLASH_CRC32_POLYNOMIAL (0xedb88320U)

CLASSB_SRAM_TEST_BUFFER_SIZE

Summary

Defines the size of the buffer used for SRAM test.

Description

This constant defines the size of the buffer used for SRAM test.

Remarks

This value must not be modified.

#define CLASSB_SRAM_TEST_BUFFER_SIZE (512U)

CLASSB_SRAM_APP_AREA_START

Summary

Defines the start address of the SRAM for the application.

Description

This constant defines the start address of the SRAM for the application. First 1kB of the SRAM is reserved for the Class B library.

Remarks

This value must not be modified.

#define CLASSB_SRAM_APP_AREA_START (0x20000400U)

CLASSB_SRAM_FINAL_WORD_ADDRESS

Summary

Final word address in the SRAM.

Description

This constant defines the final word address in the SRAM.

Remarks

This value must not be modified. Varies depending on the device.

#define CLASSB_SRAM_FINAL_WORD_ADDRESS (0x2003fffcU)

CLASSB_SRAM_BUFF_START_ADDRESS

Summary

SRAM test buffer start address.

Description

This constant defines the SRAM test buffer start address. This is used by the self-test for the SRAM.

Remarks

This value must not be modified.

#define CLASSB_SRAM_BUFF_START_ADDRESS (0x20000200U)

CLASSB_SRAM_TEMP_STACK_ADDRESS

Summary

Address of the temporary stack.

Description

This constant defines the address of the temporary stack used during SRAM self-test.

Remarks

This value must not be modified.

#define CLASSB_SRAM_TEMP_STACK_ADDRESS (0x20000100U)

CLASSB_SRAM_ALL_32BITS_HIGH

Summary

Defines name for max 32-bit unsigned value.

Description

This constant defines a name for max 32-bit unsigned value.

Remarks

This value must not be modified.

#define CLASSB_SRAM_ALL_32BITS_HIGH (0xFFFFFFFFU)

CLASSB_INTR_DEVICE_VECT_OFFSET

Summary

Defines the offset for first device specific interrupt.

Description

This constant defines the offset for first device specific interrupt.

Remarks

This value must not be modified.

#define CLASSB_INTR_DEVICE_VECT_OFFSET (16U)

CLASSB_INTR_VECTOR_TABLE_SIZE

Summary

Defines the size of the vector table.

Description

This constant defines the size of the vector table.

Remarks

This value must not be modified.

#define CLASSB_INTR_VECTOR_TABLE_SIZE (CLASSB_INTR_DEVICE_VECT_OFFSET + PERIPH_MAX_IRQn)

CLASSB_INTR_MAX_INT_COUNT

Summary

Defines the upper limit for interrupt count.

Description

This constant defines the upper limit for interrupt count for the interrupt self-test.

Remarks

This value must not be modified.

#define CLASSB_INTR_MAX_INT_COUNT (30U)

CLASSB_INTR_TEST_RTC_COUNT

Summary

Defines the counter value for RTC peripheral.

Description

This constant defines the counter value for RTC peripheral, for the interrupt self-test.

Remarks

This value must not be modified.

#define CLASSB_INTR_TEST_RTC_COUNT (50U)

CLASSB_INTR_TEST_TC_COUNT

Summary

Defines the counter value for TC0 peripheral.

Description

This constant defines the counter value for TC0 peripheral, for the interrupt self-test.

Remarks

This value must not be modified.

#define CLASSB_INTR_TEST_TC_COUNT (100U)

Data types

CLASSB_TEST_ID

Summary

Identifies Class B library tests.

Description

This enumeration can be used to read the self-test status and update it. Test ID corresponds to the bit position at which the 2-bit test result is stored.

Remarks

None.

typedef enum
{
CLASSB_TEST_CPU = 0,
CLASSB_TEST_PC = 2,
CLASSB_TEST_RAM = 4,
CLASSB_TEST_FLASH = 6,
CLASSB_TEST_CLOCK = 8,
CLASSB_TEST_INTERRUPT = 10,
CLASSB_TEST_IO = 12
} CLASSB_TEST_ID;

CLASSB_TEST_STATUS

Summary

Identifies result from Class B library test.

Description

This is return type for self-tests.

Remarks

None.

typedef enum
{
CLASSB_TEST_NOT_EXECUTED = 0,
CLASSB_TEST_PASSED = 1,
CLASSB_TEST_FAILED = 2,
CLASSB_TEST_INPROGRESS = 3
} CLASSB_TEST_STATUS;

CLASSB_TEST_STATE

Summary

Identifies Class B library test state.

Description

This data type is used to update flags which indicates whether a test has started or not.

Remarks

None.

typedef enum
{
CLASSB_TEST_NOT_STARTED = 0,
CLASSB_TEST_STARTED = 1
} CLASSB_TEST_STATE;

CLASSB_INIT_STATUS

Summary

Identifies Class B initialization status.

Description

This is return type for the function which initializes the Class B library during startup. This indicates whether the SSTs are executed or not.

Remarks

None.

typedef enum
{
CLASSB_SST_DONE = 1,
CLASSB_SST_NOT_DONE = 2
} CLASSB_INIT_STATUS;

CLASSB_STARTUP_STATUS

Summary

Identifies startup test status.

Description

This is return type for the function which calls all self-tests during startup.

Remarks

None.

typedef enum
{
CLASSB_STARTUP_TEST_PASSED = 1,
CLASSB_STARTUP_TEST_FAILED = 2
} CLASSB_STARTUP_STATUS;

CLASSB_TEST_TYPE

Summary

Identifies type of the Class B library test.

Description

There are two categories of test. They are startup tests (SSTs) and run-time tests (RSTs). Test results for SSTs and RSTs are stored at separate locations in the SRAM.

Remarks

None.

typedef enum
{
CLASSB_TEST_TYPE_SST = 0,
CLASSB_TEST_TYPE_RST = 1
} CLASSB_TEST_TYPE;

*CLASSB_SST_RESULT_BF

Summary

Pointer to the structure for the Class B library startup self-test result.

Description

For bit-field representation of Class B library test results.

Remarks

None.

typedef struct
{
CLASSB_TEST_STATUS CPU_STATUS:2;
CLASSB_TEST_STATUS PC_STATUS:2;
CLASSB_TEST_STATUS RAM_STATUS:2;
CLASSB_TEST_STATUS FLASH_STATUS:2;
CLASSB_TEST_STATUS CLOCK_STATUS:2;
CLASSB_TEST_STATUS INTERRUPT_STATUS:2;
} *CLASSB_SST_RESULT_BF;

*CLASSB_RST_RESULT_BF

Summary

Pointer to the structure for the Class B library run-time self-test result.

Description

For bit-field representation of Class B library test results.

Remarks

None.

typedef struct
{
CLASSB_TEST_STATUS CPU_STATUS:2;
CLASSB_TEST_STATUS PC_STATUS:2;
CLASSB_TEST_STATUS RAM_STATUS:2;
CLASSB_TEST_STATUS FLASH_STATUS:2;
CLASSB_TEST_STATUS CLOCK_STATUS:2;
CLASSB_TEST_STATUS UNUSED_STATUS:2;
CLASSB_TEST_STATUS IO_STATUS:2;
} *CLASSB_RST_RESULT_BF;

CLASSB_SRAM_MARCH_ALGO

Summary

Selects the RAM March algorithm to run.

Description

Selects the RAM March algorithm to be used for the SRAM self-test.

Remarks

None.

typedef enum
{
CLASSB_SRAM_MARCH_C = 0,
CLASSB_SRAM_MARCH_C_MINUS = 1,
CLASSB_SRAM_MARCH_B = 2
} CLASSB_SRAM_MARCH_ALGO;

CLASSB_PORT_INDEX

Summary

PORT index definitions for Class B library I/O pin test.

Description

This can be used in the I/O pin test.

Remarks

None.

typedef enum
{
PORTA = 0,
PORTB = 1,
PORTC = 2,
PORTD = 3
} CLASSB_PORT_INDEX;

CLASSB_PORT_PIN

Summary

PIN definitions for Class B library I/O pin test.

Description

This can be used in the I/O pin test.

Remarks

None.

typedef enum
{
PIN0 = 0,
PIN1 = 1,
PIN2 = 2,
PIN3 = 3,
PIN4 = 4,
PIN5 = 5,
PIN6 = 6,
PIN7 = 7,
PIN8 = 8,
PIN9 = 9,
PIN10 = 10,
PIN11 = 11,
PIN12 = 12,
PIN13 = 13,
PIN14 = 14,
PIN15 = 15,
PIN16 = 16,
PIN17 = 17,
PIN18 = 18,
PIN19 = 19,
PIN20 = 20,
PIN21 = 21,
PIN22 = 22,
PIN23 = 23,
PIN24 = 24,
PIN25 = 25,
PIN26 = 26,
PIN27 = 27,
PIN28 = 28,
PIN29 = 29,
PIN30 = 30,
PIN31 = 31
} CLASSB_PORT_PIN;

CLASSB_PORT_PIN_STATE

Summary

PORT pin state.

Description

This can be used in the I/O pin test.

Remarks

None.

typedef enum
{
PORT_PIN_LOW = 0,
PORT_PIN_HIGH = 1,
PORT_PIN_INVALID = 2
} CLASSB_PORT_PIN_STATE;

CLASSB_CPU_PC_TEST_VALUES

Summary

Data type for PC Test input and output values.

Description

The PC tests performs logical left-shift of the input value and returns it. Values from this enum can be used as arguments.

Remarks

None.

typedef enum classb_pc_test_val
{
CLASSB_CPU_PC_TEST_ROUTINE_A_INPUT = 1U,
CLASSB_CPU_PC_ROUTINE_A_RET_VAL = 2U,
CLASSB_CPU_PC_ROUTINE_B_RET_VAL = 4U,
CLASSB_CPU_PC_ROUTINE_C_RET_VAL = 8U,
CLASSB_CPU_PC_TEST_INIT_VAL = 0U
} CLASSB_CPU_PC_TEST_VALUES;

Interface Routines

CLASSB_ClearTestResults

Function

void CLASSB_ClearTestResults(CLASSB_TEST_TYPE test_type);

Summary

Clears the results of SSTs or RSTs.

Description

This function clears all the test results of a given type of test.

Precondition

None.

Parameters

test_type - Can be CLASSB_TEST_TYPE_SST or CLASSB_TEST_TYPE_RST.

Returns

None.

Example

CLASSB_ClearTestResults(CLASSB_TEST_TYPE_SST);
CLASSB_ClearTestResults(CLASSB_TEST_TYPE_RST);

Remarks

This function is called from CLASSB_Init().

CLASSB_GetTestResult

Function

CLASSB_TEST_STATUS CLASSB_GetTestResult(CLASSB_TEST_TYPE test_type, CLASSB_TEST_ID test_id);

Summary

Returns the result of the specified self-test.

Description

This function reads the test results from the reserved SRAM and extracts the result of the self-test specified by the input arguments.

Precondition

None.

Parameters

test_type - Can be CLASSB_TEST_TYPE_SST or CLASSB_TEST_TYPE_RST.

test_id - Identifier for a Class B library test.

Returns

None.

Example

CLASSB_TEST_STATUS classb_test_status = CLASSB_TEST_NOT_EXECUTED;
classb_test_status = CLASSB_GetTestResult(CLASSB_TEST_TYPE_SST, CLASSB_TEST_CPU);

Remarks

None.

CLASSB_TestWDT

Function

static void CLASSB_TestWDT(void);

Summary

This function tests the WatchDog Timer (WDT).

Description

This function is called from CLASSB_Init(). It tests whether the WDT can reset the device. After the WDT resets the device, the Class B library clears the test flag and proceeds to the rest of the initialization routines. Since the test flag is kept in reserved SRAM area, it is not touched by the general startup code.

Precondition

None.

Parameters

None.

Returns

None.

Example

CLASSB_TestWDT(void);

Remarks

Calling this function results in device reset by the WDT.

CLASSB_GlobalsInit

Function

static void CLASSB_GlobalsInit(void);

Summary

This function initializes the global variables for the classb library.

Description

The parameters used by the Class B library are access with the help of pointer variables. These variables are initialized by this function.

Precondition

None.

Parameters

None.

Returns

None.

Example

CLASSB_GlobalsInit();

Remarks

None.

CLASSB_Init

Function

static CLASSB_INIT_STATUS CLASSB_Init(void);

Summary

This function is executed on every device reset. This shall be called right after the reset, before any other initialization is performed.

Description

This function performs the following,

a. It initializes the global variables used by the Class B library.

b. Checks the reset cause and decides next course of action.

c. If the reset is not caused by the Class B library, it tests the reserved SRAM area, clears all self-test results and performs a WDT test.

Precondition

None.

Parameters

None.

Returns

CLASSB_SST_DONE if all SSTs are successfully executed. CLASSB_SST_NOT_DONE if SSTs are yet to be executed.

Example

CLASSB_INIT_STATUS init_status = CLASSB_Init();

Remarks

None.

CLASSB_Startup_Tests

Function

static CLASSB_STARTUP_STATUS CLASSB_Startup_Tests(void);

Summary

This function executes all startup self-tests inserted into classb.c file by the MHC.

Description

This function is called from the ‘_on_reset’ function which is the first function to be executed after a reset. If none of the self-tests are failed, this function returns ‘CLASSB_STARTUP_TEST_PASSED’. If any of the startup self-tests are failed, this function will not return. The self-tests for SRAM, Clock and Interrupt are considered non-critical since it may be possible to execute a fail-safe function after detecting a failure. In such case, the CLASSB_SelfTest_FailSafe() function is called when a failure is detected. In the case of critical failures (CPU registers or internal flash), the corresponding self-test remains in an infinite loop to avoid unsafe execution of code.

Precondition

None.

Parameters

None.

Returns

Pass or Fail.

Example

CLASSB_STARTUP_STATUS startup_tests_status = CLASSB_STARTUP_TEST_FAILED;
startup_tests_status = CLASSB_Startup_Tests();

Remarks

This function does not return if any of the self-tests detects a failure.

CLASSB_SST_WDT_Recovery

Function

static void CLASSB_SST_WDT_Recovery(void);

Summary

This function is called if a WDT reset is caused while a startup self-test is running.

Description

This function is used inside the CLASSB_Init() function. When the device comes back from a WDT reset, if there has been a startup self-test running, it is assumed that the WDT reset has happened because a Class B self-test has taken more time that the WDT timeout period. In this case, the CLASSB_SST_WDT_Recovery() function is called from CLASSB_Init().

Precondition

None.

Parameters

None.

Returns

None.

Example

if ((RSTC_REGS->RSTC_RCAUSE & RSTC_RCAUSE_WDT_Msk) == RSTC_RCAUSE_WDT_Msk)
{
    if (*classb_test_in_progress == CLASSB_TEST_STARTED)
    {
        CLASSB_SST_WDT_Recovery();
    }
}

Remarks

This function is for the internal use of the Class B library.

CLASSB_App_WDT_Recovery

Function

static void CLASSB_App_WDT_Recovery(void);

Summary

This function is called if a WDT reset is caused during run-time.

Description

This function is used inside the CLASSB_Init() function. When the device comes back from a WDT reset, if a WDT test by the Class B library has not been in progress, it is assumed that the WDT reset has happened since the application failed to clear the WDT during regular intervals. In this case, the CLASSB_App_WDT_Recovery() function is called from CLASSB_Init().

Precondition

None.

Parameters

None.

Returns

None.

Example

if ((RSTC_REGS->RSTC_RCAUSE & RSTC_RCAUSE_WDT_Msk) == RSTC_RCAUSE_WDT_Msk)
{
    if (!(*wdt_test_in_progress == CLASSB_TEST_STARTED))
    {
        CLASSB_SST_WDT_Recovery();
    }
}

Remarks

This function is for the internal use of the Class B library.

CLASSB_SelfTest_FailSafe

Function

void CLASSB_SelfTest_FailSafe(CLASSB_TEST_ID test_id);

Summary

This function is called if any of the non-critical tests are failed.

Description

The self-tests for SRAM, Clock and Interrupt are considered non-critical since it may be possible to execute a fail-safe function after detecting a failure, if the fail-safe routine does not use the failed element on the microcontroller. Default implementation of this function is available in classb.c file. The function contains an infinite loop. Further code shall be added as per the application need.

Precondition

None.

Parameters

test_id - Identification number of the failed test.

Returns

None.

Example

if (classb_sram_status == CLASSB_TEST_FAILED)
{
    CLASSB_SelfTest_FailSafe(CLASSB_TEST_RAM);
}

Remarks

This function must not return to the Class B library since it is called due to a self-test failure. Avoid using features which depend on the failed component. For example, if self-test for clock is failed, it is not advisable to use UART for error reporting since BAUD rate may not be accurate. In the case of SRAM failure, avoid the use of function calls or variables in SRAM. The error reporting mechanism in this case can be an IO pin.

CLASSB_CPU_RegistersTest

Function

CLASSB_TEST_STATUS CLASSB_CPU_RegistersTest(bool running_context);

Summary

This self-test checks the processor core registers of the CPU, to detect stuck-at faults.

Description

This self-test writes test patterns into the processor core registers and special function registers and read them back to detect stuck-at faults. Special function register bits which are reserved and should not be modified during the test, are not written.

Precondition

None.

Parameters

running_context - False for startup test. True for run-time test.

Returns

CLASSB_TEST_STATUS - Status of the test.

Example

CLASSB_TEST_STATUS classb_test_status = CLASSB_TEST_NOT_EXECUTED;
// Perform run-time test of the CPU registers
classb_test_status = CLASSB_CPU_RegistersTest(true);

Remarks

This self-test can be used during startup as well as run-time. If a failure is detected, this self-test remains in an infinite loop to avoid unsafe code execution.

CLASSB_FPU_RegistersTest

Function

CLASSB_TEST_STATUS CLASSB_FPU_RegistersTest(bool running_context);

Summary

This self-test checks the FPU registers of the CPU, to detect stuck-at faults.

Description

This self-test writes test patterns into the FPU registers, and read them back to detect stuck-at faults. Special function register bits which are reserved or should not be modified during the test, are not written. Testing FPU registers is optional as it may not be used in every application.

Precondition

None.

Parameters

running_context - False for startup test. True for run-time test.

Returns

CLASSB_TEST_STATUS - Status of the test.

Example

CLASSB_TEST_STATUS classb_test_status = CLASSB_TEST_NOT_EXECUTED;
// Perform run-time test of the FPU registers
classb_test_status = CLASSB_FPU_RegistersTest(true);

Remarks

This self-test can be used during startup as well as run-time. If a failure is detected, this self-test remains in an infinite loop to avoid unsafe code execution.

CLASSB_CPU_PCTest

Function

CLASSB_TEST_STATUS CLASSB_CPU_PCTest(bool running_context);

Summary

This self-test checks the Program Counter register (PC) of the CPU, to detect stuck-at faults.

Description

This self-test calls multiple functions in predefined order and verifies that each function is executed and returns the expected value. If the return values of all test functions are correct, the Program Counter is assumed to be working fine.

Precondition

None.

Parameters

running_context - False for startup test. True for run-time test.

Returns

CLASSB_TEST_STATUS - Status of the test.

Example

CLASSB_TEST_STATUS classb_test_status = CLASSB_TEST_NOT_EXECUTED;
// Perform run-time test of the PC
classb_test_status = CLASSB_CPU_PCTest(true);

Remarks

This self-test can be used during startup as well as run-time. If a failure is detected, this self-test remains in an infinite loop to avoid unsafe code execution.

CLASSB_FlashCRCGenerate

Function

uint32_t CLASSB_FlashCRCGenerate(uint32_t start_addr, uint32_t test_size);

Summary

Generates CRC-32 checksum for a given memory area.

Description

This function runs CRC-32 algorithm with the polynomial 0xEDB88320 and returns the generated checksum. It uses table based approach where the table is generated during the execution. It uses 0xffffffff as the initial value.

Precondition

None.

Parameters

start_addr - Starting address of the memory block.

test_size - Size of the memory block.

Returns

CLASSB_TEST_STATUS - Status of the test.

Example

uint32_t crc_val = 0;
// Generate CRC-32 for the internal Flash.
crc_val = CLASSB_FlashCRCGenerate(0, 0xFE000);

Remarks

This function is used inside the Class B library to generate CRC-32 of the internal Flash memory but it can be used on any contiguous memory area.

CLASSB_FlashCRCTest

Function

CLASSB_TEST_STATUS CLASSB_FlashCRCTest(uint32_t start_addr, uint32_t test_size, uint32_t crc_val, bool running_context);

Summary

This self-test checks the internal Flash program memory to detect single bit faults.

Description

This self-test generates CRC-32 checksum for the given memory area and compares it with the expected checksum.

Precondition

None.

Parameters

start_addr - Starting address of the memory block.

test_size - Size of the memory block.

crc_val - Expected CRC-32 checksum.

running_context - False for startup test. True for run-time test.

Returns

CLASSB_TEST_STATUS - Status of the test.

Example

CLASSB_TEST_STATUS classb_test_status = CLASSB_TEST_NOT_EXECUTED;
// Perform run-time test of the internal Flash
classb_test_status = CLASSB_FlashCRCTest(0, 0xFE000, *(uint32_t *)FLASH_CRC32_ADDR, true);

Remarks

This self-test can be used during startup as well as run-time. If a failure is detected, this self-test remains in an infinite loop to avoid unsafe code execution.

CLASSB_SRAM_MarchTestInit

Function

CLASSB_TEST_STATUS CLASSB_SRAM_MarchTestInit(uint32_t * start_addr, uint32_t test_size, CLASSB_SRAM_MARCH_ALGO march_algo, bool running_context);

Summary

This self-test checks the SRAM with the help of RAM March algorithm.

Description

This self-test run the selected RAM March algorithm on the SRAM to detect stuck-at fault, DC fault and addressing fault.

Precondition

None.

Parameters

start_addr - Starting address of the memory block.

test_size - Size of the memory block.

march_algo - The selected RAM March algorithm. It can be March C, March C minus or March B.

running_context - False for startup test. True for run-time test.

Returns

CLASSB_TEST_STATUS - Status of the test.

Example

CLASSB_TEST_STATUS classb_test_status = CLASSB_TEST_NOT_EXECUTED;
// Perform run-time test of the internal SRAM
classb_test_status = CLASSB_SRAM_MarchTestInit((uint32_t *)CLASSB_SRAM_APP_AREA_START,
    1024, CLASSB_SRAM_MARCH_C, true);

Remarks

This self-test can be used during startup as well as run-time. Initial 1kB of the SRAM must be reserved for the Class B library.

CLASSB_ClockTest

Function

CLASSB_TEST_STATUS CLASSB_ClockTest(uint32_t cpu_clock_freq, uint8_t error_limit, uint16_t clock_test_rtc_cycles, bool running_context);

Summary

This self-test checks whether the CPU clock frequency is within the permissible limit.

Description

This self-test uses RTC and SysTick to measure the CPU clock frequency. The RTC is clocked at 32768 Hz from the XOSC32K and CPU clock can be from any other high frequency oscillator. If the CPU clock frequency is within specified error limit, it returns PASS. The test duration is defined by the value of rtc_cycles. The RTC is configured to take clock from an external 32.768 kHz accurate crystal.

Precondition

None.

Parameters

cpu_clock_freq - Expected CPU clock frequency.

error_limit - Permissible error limit (eg; 5 means +-5 percent).

clock_test_rtc_cycles - The test duration in terms of RTC cycles.

running_context - False for startup test. True for run-time test.

Returns

CLASSB_TEST_STATUS - Status of the test.

Example

CLASSB_TEST_STATUS classb_test_status = CLASSB_TEST_NOT_EXECUTED;
// Perform run-time test of the CPU clock
classb_test_status = CLASSB_ClockTest(120000000, 5, 500, true);

Remarks

This self-test can be used during startup as well as run-time. This self-test shall be used only if there is an external 32.768 kHz accurate crystal connected to the XOSC32K of the microcontroller.

CLASSB_SST_InterruptTest

Function

CLASSB_TEST_STATUS CLASSB_SST_InterruptTest(void);

Summary

This self-test checks basic functionality of the interrupt handling mechanism.

Description

This self-test configures the Nested Vectored Interrupt Controller (NVIC), the RTC peripheral and the TC0 peripheral to test the interrupt handling mechanism of the microcontroller. It verifies that at least one interrupt is generated and handled properly. This self-test also checks whether the number of interrupts generated are too many within a given time period. It reports a PASS if the RTC has generated at least one interrupt and the total number of interrupts generated by the TC0 is less than the specified upper limit and greater than one. The clock used for RTC is 1kHz from the internal OSCULP32K and for TC0, the clock is same as the default CPU clock (48MHz from the DFLL48M).

Precondition

None.

Parameters

None.

Returns

CLASSB_TEST_STATUS - Status of the test.

Example

CLASSB_TEST_STATUS classb_test_status = CLASSB_TEST_NOT_EXECUTED;
// Perform test of the Interrupt mechanism at start-up
classb_test_status = CLASSB_SST_InterruptTest();

Remarks

This self-test can be used only during startup.

CLASSB_RST_IOTest

Function

CLASSB_TEST_STATUS CLASSB_RST_IOTest(CLASSB_PORT_INDEX port, CLASSB_PORT_PIN pin, CLASSB_PORT_PIN_STATE state);

Summary

This self-test can be used to perform plausibility checks on IO pins.

Description

This self-test checks whether a given IO pin is at the expected logic state. As the exact use of an IO pin is decide by the application, it is the responsibility of the caller to configure the IO pin direction and drive the pin to the expected state before calling this self-test.

Precondition

Before testing an output pin, call CLASSB_IO_InputSamplingEnable() function to enable input sampling for the IO pin.

Parameters

port - Index of the IO PORT. Defined by enum CLASSB_PORT_INDEX.

pin - Index of the pin on the given PORT. Defined by enum CLASSB_PORT_PIN.

state - Expected logic state of the IO pin. It can be PORT_PIN_LOW or PORT_PIN_HIGH.

Returns

CLASSB_TEST_STATUS - Status of the test.

Example

CLASSB_TEST_STATUS classb_test_status = CLASSB_TEST_NOT_EXECUTED;
// Perform test of an IO pin at run-time
classb_test_status = CLASSB_RST_IOTest(PORTB, PIN31, PORT_PIN_HIGH);

Remarks

This self-test can be used only during run-time.

CLASSB_IO_InputSamplingEnable

Function

void CLASSB_IO_InputSamplingEnable(CLASSB_PORT_INDEX port, CLASSB_PORT_PIN pin);

Summary

Enable input sampling for an IO pin.

Description

Before testing an output pin with CLASSB_RST_IOTest() API, call this function to enable input sampling, so that the ‘IN’ register will have the data from the port pin.

Precondition

None.

Parameters

port - Index of the IO PORT. Defined by enum CLASSB_PORT_INDEX.

pin - Index of the pin on the given PORT. Defined by enum CLASSB_PORT_PIN.

state - Expected logic state of the IO pin. It can be PORT_PIN_LOW or PORT_PIN_HIGH.

Returns

CLASSB_TEST_STATUS - Status of the test.

Example

CLASSB_TEST_STATUS classb_test_status = CLASSB_TEST_NOT_EXECUTED;
// Perform test of an IO pin at run-time
classb_test_status = CLASSB_RST_IOTest(PORTB, PIN31, PORT_PIN_HIGH);

Remarks

This self-test can be used only during run-time.