Class EpdIF
FlashMemoryClass Class
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.
#include <FlashMemory.h>
void setup() {
FlashMemory.read();
if (FlashMemory.buf[0] == 0xFF) {
FlashMemory.buf[0] = 0x00;
FlashMemory.update();
Serial.println(“write count to 0”);
} else {
FlashMemory.buf[0]++;
FlashMemory.update();
Serial.print(“Boot count: “);
Serial.println(FlashMemory.buf[0]);
}
}
void loop() {
delay(1000);
}
Example: ReadWriteOneWord
This example shows how to request flash memory larger than default
0x4000, and read/write one specific word (32-bit).
#include <FlashMemory.h>
void setup() {
unsigned int value;
/* request flash size 0x4000 from 0xFC000 */
FlashMemory.begin(0xFC000, 0x4000);
/* read one word (32-bit) from 0xFC000 plus offset 0x3F00 */
value = FlashMemory.readWord(0x3F00);
printf(“value is 0x%08Xrn”, value);
if (value == 0xFFFFFFFF) {
value = 0;
} else {
value++;
}
/* write one word (32-bit) to 0xFC000 plus offset 0x3F00 */
FlashMemory.writeWord(0x3F00, value);
}
void loop() {
// put your main code here, to run repeatedly:
}
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.
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;
Notes and Warnings
Include “FlashMemory.h” to use the class function.