3.18.1 NVMCTRL

- Non-Volatile Memory Controller

3.18.1.1 Introduction

The NVM module provides run-time read and write access to the Program Flash Memory (PFM), Data Flash Memory (DFM) and Configuration bits. PFM includes the program memory and user ID space while DFM is also referred to as EEPROM which is accessed one byte at a time and the erase before write is automatic.

3.18.1.2 Supported Device Families

PIC12F184xPIC16F184xPIC16F178xPIC16F194x
PIC18F-K20PIC18F-K22PIC18F-K40PIC18F-K42
PIC18F-K50PIC18F-K80PIC18F-K83PIC18F-K90

3.18.1.3 Required header files:


#include "mcc_generated_files/nvm/nvm.h"

3.18.1.4 How to use the Memory Driver

The Memory driver can be used to access different types of memory. Click the links below to view examples on how to access the Flash and EEPROM memory.

3.18.1.5 Module Documentation

3.18.1.5.1 Non-Volatile Memory

This file contains API prototypes and other data types for the Non-Volatile Memory (NVM) driver.

Module description

This file contains API prototypes and other data types for the Non-Volatile Memory (NVM) driver.

Version: NVM Driver Version 1.0.0
Typedefs
Functions

Definition Documentation

EEPROM_SIZE

#define EEPROM_SIZE (1024U)

Contains the size of EEPROM in bytes.

EEPROM_START_ADDRESS

#define EEPROM_START_ADDRESS (0x310000U)

Contains the starting address of EEPROM.

PROGMEM_PAGE_SIZE

#define PROGMEM_PAGE_SIZE (128U)

Contains the size of a Flash page in bytes.

PROGMEM_SIZE

#define PROGMEM_SIZE (0x020000U)

Contains the size of Flash in bytes.

UNLOCK_KEY

#define UNLOCK_KEY (0xAA55U)

Contains the unlock key required for the NVM operations.

Typedef Documentation

configuration_address_t

typedef uint24_t configuration_address_t

Data type for the Configurations Settings address.

configuration_data_t

typedef uint8_t configuration_data_t

Data type for the Configurations Settings data.

device_id_data_t

typedef uint16_t device_id_data_t

Data type for the Device ID data.

eeprom_address_t

typedef uint24_t eeprom_address_t

Data type for the EEPROM address.

eeprom_data_t

typedef uint8_t eeprom_data_t

Data type for the EEPROM data.

flash_address_t

typedef uint24_t flash_address_t

Data type for the Flash address.

flash_data_t

typedef uint8_t flash_data_t

Data type for the Flash data.

Function Documentation

CONFIGURATION_Read()

configuration_data_t CONFIGURATION_Read (configuration_address_t address)

Reads one Configuration byte.

Parameters:
in address

- Configuration byte address to be read.

Returns:

Configuration byte data.

CONFIGURATION_Write()

void CONFIGURATION_Write (configuration_address_t address, configuration_data_t data)

Writes one Configuration byte. The NVM busy status must be checked using the NVM_IsBusy() API to know if the write operation is completed.

Use the NVM_StatusGet() API to see the result of the write operation.
Precondition:

Set the unlock key using the NVM_UnlockKeySet() API, if the key has been cleared before. AoU: Address Qualifiers must be configured to Require under Project Properties>XC8 Compiler>Optimizations.

Parameters:
in address

- Configuration byte address to be written.

in data

- Configuration byte to be written.

Returns:

None.

DeviceID_Read()

device_id_data_t DeviceID_Read (device_id_address_t address)

Reads the Device ID.

Parameters:
in address

- Starting address of the Device ID.

Returns:

Device ID.

EEPROM_Read()

eeprom_data_t EEPROM_Read (eeprom_address_t address)

Reads one byte from the given EEPROM address.

Parameters:
in address

- Address of the EEPROM location to be read.

Returns:

Byte read from the given EEPROM address.

EEPROM_Write()

void EEPROM_Write (eeprom_address_t address, eeprom_data_t data)

Writes one byte to the given EEPROM address. The NVM busy status must be checked using the NVM_IsBusy() API to know if the write operation is completed.

Use the NVM_StatusGet() API to see the result of the write operation.
Precondition:

Set the unlock key using the NVM_UnlockKeySet() API, if the key has been cleared before. AoU: Address Qualifiers must be configured to Require under Project Properties>XC8 Compiler>Optimizations.

Parameters:
in address

- Address of the EEPROM location to be written.

in data

- Byte to be written to the given EEPROM location.

Returns:

None.

FLASH_PageAddressGet()

flash_address_t FLASH_PageAddressGet (flash_address_t address)

Returns the starting address of the page (the first byte location) containing the given Flash address.

Parameters:
in address

- Flash address for which the page starting address will be obtained.

Returns:

Starting address of the page containing the given Flash address.

FLASH_PageErase()

nvm_status_t FLASH_PageErase (flash_address_t address)

Erases one Flash page containing the given address.

Precondition:

Set the unlock key using the NVM_UnlockKeySet() API, if the key has been cleared before. AoU: Address Qualifiers must be configured to Require under Project Properties>XC8 Compiler>Optimizations.

Parameters:
in address

- Any address in the Flash page to be erased.

Returns:

Status of the Flash page erase operation as described in nvm_status_t.

FLASH_PageOffsetGet()

uint16_t FLASH_PageOffsetGet (flash_address_t address)

Returns the offset from the starting address of the page (the first byte location).

Parameters:
in address

- Flash address for which the offset from the starting address of the page will be obtained.

Returns:

Offset of the given address from the starting address of the page.

FLASH_Read()

flash_data_t FLASH_Read (flash_address_t address)

Reads a byte from the given address of Flash.

Parameters:
in address

- Address of the Flash location from which data is to be read.

Returns:

Byte read from the given Flash address.

FLASH_RowWrite()

nvm_status_t FLASH_RowWrite (flash_address_t address, flash_data_t * dataBuffer)

Writes one entire Flash row (page) from the given starting address of the row (the first byte location). The size of the input buffer must be one Flash row and the address must be aligned with the row boundary. Use FLASH_PageAddressGet() to obtain the starting address of the row.

Precondition:

Erase Flash row before calling this function. Set the unlock key using the NVM_UnlockKeySet() API, if the key has been cleared before. AoU: Address Qualifiers must be configured to Require under Project Properties>XC8 Compiler>Optimizations.

Parameters:
in address

- Starting address of the Flash row to be written.

in *dataBuffer

- Pointer to a buffer which holds the data to be written. If the data is already available in the buffer RAM, then an array with BUFFER_RAM_START_ADDRESS must be used.

Returns:

Status of the Flash row write operation as described in nvm_status_t.

NVM_CallbackRegister()

void NVM_CallbackRegister (void(*)(void) CallbackHandler)

Setter function for the NVM interrupt callback.

Parameters:
in CallbackHandler

- Pointer to a custom callback.

Returns:

None.

NVM_Initialize()

void NVM_Initialize (void )

Initializes the NVM driver.

Parameters:
None.
Returns:

None.

NVM_InterruptDisable()

void NVM_InterruptDisable (void )[inline]

Disables the NVM interrupt.

Parameters:
None.
Returns:

None.

NVM_InterruptEnable()

void NVM_InterruptEnable (void )[inline]

Enables the NVM interrupt.

Precondition:

Enable the global interrupt.

Parameters:
None.
Returns:

None.

NVM_IsBusy()

bool NVM_IsBusy (void )

Checks if the NVM is busy with the read/write/erase commands.

Parameters:
None.
Return values:
True

- The NVM operation is being performed.

False

- The NVM operation is not being performed.

NVM_StatusClear()

void NVM_StatusClear (void )

Clears the NVM error status.

Parameters:
None.
Returns:

None.

NVM_StatusGet()

nvm_status_t NVM_StatusGet (void )

Returns the status of the last NVM operation.

Parameters:
None.
Return values:
NVM_OK

- The NVM operation succeeded.

NVM_ERROR

- The NVM operation failed.

NVM_UnlockKeyClear()

void NVM_UnlockKeyClear (void )

Clears the previously configured unlock keys.

Parameters:
None.
Returns:

None.

NVM_UnlockKeySet()

void NVM_UnlockKeySet (uint16_t unlockKey)

Sets the unlock keys required to perform any erase or write operations on Flash and EEPROM.

Parameters:
in unlockKey

- Unlock key value specified in the device data sheet.

Returns:

None.

Enumeration Type Documentation

nvm_status_t

enum nvm_status_t

Contains the return codes for the NVM APIs.

NVM_OK

0 - The NVM operation succeeded.

NVM_ERROR

1 - The NVM operation failed.

3.18.1.5.2 Nvm_example

Flash Examples

This example shows how to overwrite an entire Flash page with the new data using the row write feature:
#include "mcc_generated_files/system/system.h"

#define FLASH_ADDRESS (PROGMEM_SIZE - 5) //Flash address at which data is to be written

void FLASH_Example_PageErase_RowWrite_Read(void)
{
    flash_address_t flashStartPageAddress;
    uint16_t index;
    flash_data_t flashWriteData[PROGMEM_PAGE_SIZE];
    nvm_status_t errorStatus = NVM_OK;
    bool readError = false;

    //Get the starting address of the page containing the given address
    flashStartPageAddress = FLASH_PageAddressGet(FLASH_ADDRESS);
  
    //Erase entire page 
    NVM_UnlockKeySet(UNLOCK_KEY);     
    errorStatus = FLASH_PageErase(flashStartPageAddress);
    NVM_UnlockKeyClear();
    if (errorStatus == NVM_OK)
    {
        printf("FLASH_PageErase passed \r\n");
    }
    else
    {
        printf("FLASH_PageErase failed \r\n");
        NVM_StatusClear();
    }

    //Prepare row data
    for (index = 0; index < PROGMEM_PAGE_SIZE; index++)
    {
        flashWriteData[index] = (flash_data_t) index;
    }

    //Write data to Flash row  
    NVM_UnlockKeySet(UNLOCK_KEY);
    errorStatus = FLASH_RowWrite(flashStartPageAddress, flashWriteData);
    NVM_UnlockKeyClear();
    if (errorStatus == NVM_OK)
    {
        printf("FLASH_RowWrite passed \r\n");
    }
    else
    {
        printf("FLASH_RowWrite failed \r\n");
        NVM_StatusClear();
    }

    //Read and verify row data
    for (index = 0; index < PROGMEM_PAGE_SIZE; index++)
    {
        if (FLASH_Read(flashStartPageAddress + index) != flashWriteData[index])
        {
            readError = true;
            break;
        }
    }

    if (readError == false)
    {
        printf("FLASH_Read passed \r\n");
    }
    else
    {
        printf("FLASH_Read failed \r\n");
    }
}
This example shows how to update specific locations in the given Flash page without disturbing other locations:
#include "mcc_generated_files/system/system.h"

#define FLASH_ADDRESS (PROGMEM_SIZE - 5) //Flash address at which data is to be written

void FLASH_Example_UpdateSelectiveLocations(void)
{
    flash_address_t flashStartPageAddress;
    uint16_t flashAddressOffset;
    nvm_status_t errorStatus = NVM_OK;
    bool readError = false;    
    flash_data_t flashWriteData[PROGMEM_PAGE_SIZE];

    //Get the starting address of the page containing the given address
    flashStartPageAddress = FLASH_PageAddressGet(FLASH_ADDRESS);
    for (flashAddressOffset = 0; flashAddressOffset < PROGMEM_PAGE_SIZE; flashAddressOffset++)
    {
        flashWriteData[flashAddressOffset] = FLASH_Read(flashStartPageAddress + flashAddressOffset);
    }

    //Get offset from starting address of the page
    flashAddressOffset = FLASH_PageOffsetGet(FLASH_ADDRESS);

    //Update 4 bytes 
    flashWriteData[flashAddressOffset] = 0x0A;
    flashWriteData[flashAddressOffset + 1] = 0x1A;
    flashWriteData[flashAddressOffset + 2] = 0x2A;
    flashWriteData[flashAddressOffset + 3] = 0x3A;

    //Erase entire Flash page    
    NVM_UnlockKeySet(UNLOCK_KEY);   
    errorStatus = FLASH_PageErase(flashStartPageAddress);
    NVM_UnlockKeyClear();
    if (errorStatus == NVM_OK)
    {
        printf("FLASH_PageErase passed \r\n");
    }
    else
    {
        printf("FLASH_PageErase failed \r\n");
        NVM_StatusClear();
    }

    //Write data to Flash row  
    NVM_UnlockKeySet(UNLOCK_KEY);
    errorStatus = FLASH_RowWrite(flashStartPageAddress, flashWriteData);
    NVM_UnlockKeyClear();
    if (errorStatus == NVM_OK)
    {
        printf("FLASH_RowWrite passed \r\n");
    }
    else
    {
        printf("FLASH_RowWrite failed \r\n");
        NVM_StatusClear();
    }

    //Read and verify row data
    for (flashAddressOffset = 0; flashAddressOffset < PROGMEM_PAGE_SIZE; flashAddressOffset++)
    {
        if (FLASH_Read(flashStartPageAddress + flashAddressOffset) != flashWriteData[flashAddressOffset])
        {
            readError = true;
            break;
        }
    }

    if (readError == false)
    {
        printf("FLASH_Read passed \r\n");
    }
    else
    {
        printf("FLASH_Read failed \r\n");
    }
}

EEPROM Examples

This example shows how to perform the write and read operations on EEPROM:
#include "mcc_generated_files/system/system.h"

#define EEPROM_ADDRESS (EEPROM_START_ADDRESS) //EEPROM address at which data is to be written

void EEPROM_Write_Read(void)
{
    eeprom_data_t eepromWriteData[8];
    uint8_t count;
    bool readError = false;

    //Prepare data
    for (count = 0; count < 8; count++)
    {
        eepromWriteData[count] = 0xA1 + count;
    }

    for (count = 0; count < 8; count++)
    {
        //Write EEPROM byte    
        NVM_UnlockKeySet(UNLOCK_KEY);
        EEPROM_Write(EEPROM_ADDRESS + count, eepromWriteData[count]);
        NVM_UnlockKeyClear();
        while (NVM_IsBusy());
        if (NVM_StatusGet() == NVM_OK)
        {
            printf("EEPROM_Write passed \r\n");
        }
        else
        {
            printf("EEPROM_Write failed \r\n");
            NVM_StatusClear();
        }
    }

    //Read and verify
    for (count = 0; count < 8; count++)
    {
        if (EEPROM_Read(EEPROM_ADDRESS + count) != eepromWriteData[count])
        {
            readError = true;
            break;
        }
    }

    if (readError == false)
    {
        printf("EEPROM_Read passed \r\n");
    }
    else
    {
        printf("EEPROM_Read failed \r\n");
    }
}

Device ID Examples

This example shows how to read the Device ID:
#include "mcc_generated_files/system/system.h"

#define DEVICE_ID_ADDRESS (0x3FFFFEU) //(Compare with the device data sheet to see if the address is correct)

void NVM_Example_DeviceID_Read(void)
{
    printf("Device ID : 0x%X \r\n", DeviceID_Read(DEVICE_ID_ADDRESS));
}

Configuration Settings Examples

This example shows how to update the specific Configuration setting without disturbing the other settings:
#include "mcc_generated_files/system/system.h"

#define CONFIG_TO_BE_UPDATED_ADDRESS (0x300000U) //CONFIG1 address (Compare with the device data sheet to see if the address is correct)
#define _CONFIG1_FEXTOSC_MASK (0b111)

void NVM_Example_Configuration_UpdateSpecifcSetting(void)
{
    configuration_address_t configurationToBeUpdatedAddress = CONFIG_TO_BE_UPDATED_ADDRESS;   
    configuration_data_t configurationValueToBeUpdated;
   
    //Read
    configurationValueToBeUpdated = CONFIGURATION_Read(configurationToBeUpdatedAddress);
    
    //Modify
    configurationValueToBeUpdated &= (~((configuration_data_t)_CONFIG1_FEXTOSC_MASK)); //Clear External Oscillator Mode Selection bits
    
    //Write
    NVM_UnlockKeySet(UNLOCK_KEY);
    CONFIGURATION_Write(configurationToBeUpdatedAddress, configurationValueToBeUpdated);
    NVM_UnlockKeyClear();
    while (NVM_IsBusy());
    if (NVM_StatusGet() == NVM_OK)
    {
        printf("CONFIGURATION_Write passed \r\n");
    }
    else
    {
        printf("CONFIGURATION_Write failed \r\n");
        NVM_StatusClear();
    }
    
    //Read again to verify
    if(configurationValueToBeUpdated == CONFIGURATION_Read(configurationToBeUpdatedAddress))
    {
        printf("CONFIGURATION_Read passed \r\n");
    }
    else
    {
        printf("CONFIGURATION_Read failed \r\n");
    }
}

3.18.1.6 File Documentation

3.18.1.6.1 source/nvm.c File Reference

This file contains the API implementations for the Non-Volatile Memory (NVM) driver.

#include "../nvm.h"

Functions

Detailed Description

This file contains the API implementations for the Non-Volatile Memory (NVM) driver.

Version: NVM Driver Version 1.0.0

Function Documentation

__interrupt()

void __interrupt (irq(NVM) , base(8) , low_priority )

Variable Documentation

NVM_Callback

void(* NVM_Callback) (void) = NULL[static]

unlockKeyHigh

__near static volatile uint8_t unlockKeyHigh[static]

unlockKeyLow

__near static volatile uint8_t unlockKeyLow[static]

3.18.1.6.2 source/nvm.h File Reference

#include <xc.h>
#include <stdbool.h>

Functions

Typedefs

3.18.1.6.3 source/nvm_example.dox File Reference