Class FlashMemory

Description

Defines a class of Flash memory API

Syntax

class FlashMemoryClass

Members

Public Constructors

Fl ashMemoryClass::FlashMemoryClass

Constructs a FlashMemoryClass object

Fla shMemoryClass::~FlashMemoryClass

Deconstructs a FlashMemoryClass object

Public Methods

FlashMemoryClass::begin

Initialize/Re-initialize the base address and size

FlashMemoryClass::read

Read the content to buf

FlashMemoryClass::update

Write buf back to flash memory

FlashMemoryClass::readWord

Read 4 bytes from flash memory

FlashMemoryClass::writeWord

Write 4 bytes into flash memory

FlashMemoryClass::buf_size

The buf size

FlashMemoryClass::*buf

The buf to be operated
FlashMemoryClass::FlashMemoryClass

Description

Constructs a FlashMemoryClass object.

Syntax

FlashMemoryClass(unsigned int _base_address, unsigned int _buf_size);

Parameters

\_base_address : The base address to operate.

\_buf_size : The buf size for mirror a copy to reduce flash memory operation

Returns

The function returns nothing.

Example Code

Example: FleshMemory_Basic

This example demonstrates the basic use of flash memory. Since boot count is stored in flash, each time upon device boot up, the boot count will be read from the flash, add one, then write back to the flash. Ameba’s flash memory can be edit in a unit of a sector which has the size of 4K bytes. Direct read from flash memory is allowed. To write data into flash memory, each bit on flash memory can only change from ‘1’ to ‘0’ and it cannot change from ‘0’ to ‘1’. To make sure the data are correctly written we do erase the flash memory sector before write data on it.

FlashMemory_Basic
 1  #include "FlashMemory.h"
 2
 3  void setup() {
 4    FlashMemory.read();
 5    if (FlashMemory.buf[0] == 0xFF) {
 6      FlashMemory.buf[0] = 0x00;
 7      FlashMemory.update();
 8      Serial.println("write count to 0");
 9    } else {
10      FlashMemory.buf[0]++;
11      FlashMemory.update();
12      Serial.print("Boot count: ");
13      Serial.println(FlashMemory.buf[0]);
14    }
15  }
16
17  void loop() {
18    delay(1000);
19  }  }

Example: ReadWriteOneWord

This example shows how to request flash memory larger than default 0x4000, and read/write one specific word (32-bit).

ReadWriteOneWord
 1#include "FlashMemory.h"
 2
 3void setup() {
 4  unsigned int value;
 5  /* request flash size 0x4000 from 0xFC000 */
 6  FlashMemory.begin(0xFC000, 0x4000);
 7
 8  /* read one word (32-bit) from 0xFC000 plus offset 0x3F00 */
 9  value = FlashMemory.readWord(0x3F00);
10
11  printf("value is 0x%08X\r\n", value);
12
13  if (value == 0xFFFFFFFF) {
14    value = 0;
15  } else {
16    value++;
17  }
18
19  /* write one word (32-bit) to 0xFC000 plus offset 0x3F00 */
20  FlashMemory.writeWord(0x3F00, value);
21}
22
23void loop() {
24  // put your main code here, to run repeatedly:
25}

Notes and Warnings

Include “FlashMemory.h” to use the class function.

FlashMemoryClass::begin

Description

Initialize/Re-initialize the base address and size. The base address shell aligns with the size of 0x1000. And the size shell is multiple of 0x1000.

Syntax

void begin(unsigned int _base_address, unsigned int _buf_size);

Parameters

_base_address: The base address

_buf_size : The desired work size

Returns

The function returns nothing.

Example Code

Example: FleshMemory_Basic

This example demonstrates the basic use of flash memory. Since boot count is stored in flash, each time upon device boot up, the boot count will be read from the flash, add one, then write back to the flash. Ameba’s flash memory can be edit in a unit of a sector which has the size of 4K bytes.

Example: ReadWriteOneWord

This example shows how to request flash memory larger than default 0x4000, and read/write one specific word (32-bit). Details of the example codes can be found in the previous section of FlashMemoryClass:: FlashMemoryClass.

Notes and Warnings

Include “FlashMemory.h” to use the class function.

FlashMemoryClass::read

Description

Read the content to buf. Read flash memory into the buf. The size would be 0x1000.

Syntax

void read(void);

Parameters

The function requires no input parameter.

Returns

The function returns nothing.

Example Code

Example: FleshMemory_Basic

This example demonstrates the basic use of flash memory. Since boot count is stored in flash, each time upon device boot up, the boot count will be read from the flash, add one, then write back to the flash. Ameba’s flash memory can be edit in a unit of a sector which has the size of 4K bytes. Details of the example codes can be found in the previous section of FlashMemoryClass:: FlashMemoryClass.

Notes and Warnings

Include “FlashMemory.h” to use the class function.

FlashMemoryClass::update

Description

Write buf back to flash memory. Write flash memory with the content of the buffer. The size is 0x1000.

Syntax

void update(bool erase = true);

Parameters

erase: By default, it is true and erases flash memory before writing to it

Returns

The function returns nothing.

Example Code

Example: FleshMemory_Basic

This example demonstrates the basic use of flash memory. Since boot count is stored in flash, each time upon device boot up, the boot count will be read from the flash, add one, then write back to the flash. Ameba’s flash memory can be edit in a unit of a sector which has the size of 4K bytes. Details of the example codes can be found in the previous section of FlashMemoryClass:: FlashMemoryClass.

Notes and Warnings

Include “FlashMemory.h” to use the class function.

FlashMemoryClass::readWord

Description

Read 4 bytes from flash memory. Read 4 byte from specific offset based on base address.

Syntax

unsigned int readWord(unsigned int offset);

Parameters

offset : The offset according to the base address

Returns

The read data with a size of 4 bytes

Example Code

Example: ReadWriteOneWord

This example shows how to request flash memory larger than default 0x4000, and read/write one specific word (32-bit). Details of the example codes can be found in the previous section of FlashMemoryClass:: FlashMemoryClass.

Notes and Warnings

Include “FlashMemory.h” to use the class function.

FlashMemoryClass::writeWord

Description

Write 4 bytes into flash memory. It will try to write 4 bytes first. If the read data differ from the write data, then we buffer the sector of flash memory, erase it, and write correct data back to it.

Syntax

void writeWord(unsigned int offset, unsigned int data);

Parameters

offset : The offset according to the base address

data : The data to be written

Returns

The function returns nothing.

Example Code

Example: ReadWriteOneWord

This example shows how to request flash memory larger than default 0x4000, and read/write one specific word (32-bit). Details of the example codes can be found in the previous section of FlashMemoryClass:: FlashMemoryClass.

Notes and Warnings

Include “FlashMemory.h” to use the class function.

FlashMemoryClass::buf_size

Description

The buf size (It can be regarded as work size).

Syntax

unsigned int buf_size;

Example Code

Example: FlashMemory_Basic

This example demonstrates the basic use of flash memory. Since boot count is stored in flash, each time upon device boot up, the boot count will be read from the flash, add one, then write back to the flash. Ameba’s flash memory can be edit in a unit of a sector which has the size of 4K bytes. Details of the example codes can be found in the previous section of FlashMemoryClass:: FlashMemoryClass.

Notes and Warnings

Include “FlashMemory.h” to use the class function.

FlashMemoryClass::*buf

Description

The buf to be operated. Modify buf won’t change the content of the buf. It needs an update to write back to flash memory.

Syntax

unsigned char *buf;

Example Code

NA

Notes and Warnings

Include “FlashMemory.h” to use the class function.