Electrical – What operations on flash(NOR/NAND) effect Flash Program/Erase(P/E) cycles

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I want to implement a counter which can save values through power cycles, so I should use flash memory(I have option to choose NOR or NAND) but as my counter values will be increased frequently. I want to optimize number of erases(considering only erases i.e making bits 0 to 1 will effect the flash life span).

For that I want to implement tick counter In which sequence of bytes(around KBytes, depends on my counter maximum value, usually equal to block size) allocated to counter for each increment successive bits will be set to 1 to 0 starting from MSB. I will write custom flash driver to take care of counter operations.

Ex:

Val0: 1111 1111 1111 1111 ....
Val1: 0111 1111 1111 1111 ....
Val2: 0011 1111 1111 1111 ....

Advantages tick counter:

Erase required only when we want to make counter to zero.

But is it possible to program a bit from 1 to 0 without erasing(NAND/NOR), if yes will that effect P/E cycles count?

Best Answer

Rethink your choice of component selection and design in a FRAM chip instead. These support much better performance than Flash because there are no long operational delays on writes and erases. FRAM chips also have endurance capabilities that far out pace those of Flash or EEPROM.

The FRAM chips that I use also support byte by byte data changing as well. This allows for the design of stored block type data in the FRAM chip to be buffered in RAM and then only needing to update specific bytes that have changed as opposed to whole blocks like in Flash. This performance improvement alone can make the serial nature of a SPI or I²C interfaced FRAM chip not bog down an application.

Related Solutions

Electronic – How is NAND Flash memory array organized

The image of the part number you have shared implies that its a 2-Plane NAND Flash chip.

A Page is 2,048 + 64 Bytes long, 64 such pages forms one Block.

So,

size of 1 Block = size of 64 Pages
                = 2,112 x 64 Bytes
                = 1,35,168 Bytes
                = 10,81,344 bits
                = 1056 Kb

Now, 1 Plane consists of 1024 such Blocks. So,

size of 1 Plane = 1024 x 2112 x 64 Bytes 
                = 1024 x 1056 Kb
                = 13,84,12,032 Bytes
                = 1,10,72,96,256 bits
                = 1,056 Mb

Since the device has two such planes, Memory size of 1 Device = 1,056 x 2 = 2,112 Mb.

Kindly note that 2112 Bytes each for Cache Register and Data Register are not being counted in the sum of total memory, since it is not a non-volatile memory.

Additionally, the advantage of having two blocks is:

Memory can be divided into two physical planes, odd/even blocks
Users have the ability to:
<•> Concurrently access two pages for read
<•> Erase two blocks concurrently
<•> Program two pages concurrently
Provided that, the page addresses of blocks from both planes must be the same during two-plane Read/Program/Erase operations.

Electronic – Can´t erase data from flash memory (STM32)

I found the solution. I used HAL_FLASH_Lock() function instead of HAL_FLASHEx_Erase() function and it works fine. I also changed SECTOR because I was accidently erasing my program.

unit32_t address = 0x0800C000;
HAL_FLASH_Unlock();
__HAL_FLASH_CLEAR_FLAG(FLASH_FLAG_EOP | FLASH_FLAG_OPERR | FLASH_FLAG_WRPERR | FLASH_FLAG_PGAERR | FLASH_FLAG_PGPERR | FLASH_FLAG_PGSERR);

FLASH_Erase_Sector(FLASH_SECTOR_3, VOLTAGE_RANGE_3);

//----------------------------write data  
uint8_t data = 'A';
if (HAL_FLASH_Program(TYPEPROGRAM_BYTE, start_address, data) != HAL_OK) {
    HAL_FLASH_Lock();
    return;
}
HAL_FLASH_Lock();

Thanks for your help.

Best Answer

Related Solutions

Electronic – How is NAND Flash memory array organized

Electronic – Can´t erase data from flash memory (STM32)

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