I would like to ask about the CORTEXT M0+ memory erase and write problem

深圳小花

I would like to ask about the CORTEXT M0+ memory erase and write problem [Copy link]

邀请：@maychang   @damiaa   @huo_hu   @dcexpert   参与回复

Please ask

1. Regarding the erasing of CORTEXT M0+ memory, when erasing the FLASH memory by page, is the entire page erased at the same time, or are each byte in the page erased one by one?

2. Why do you need to erase before writing?

maychang

"When erasing the FLASH memory page by page, does it erase the entire page at the same time, or does it erase each byte in the page one by one?"

It is a full page erase, not a byte-by-byte erase.

In addition, it is impossible to erase "at the same moment" and erasing takes a relatively long time.

maychang

"Why do you have to erase first before you can write again?"

Unlike RAM, this type of memory can only write "0" but not "1". To write "1", it can only be erased (after erasing, all bits of all bytes become "1"). After erasing, rewriting will only write "0" and the bits that are "1" will not be written and remain the same.

深圳小花

maychang posted on 2021-7-10 10:00 "Is the FLASH memory erased and written at the same time, or each byte in the page is erased and written one by one? "Yes...

Thank you very much. How long does it take to erase a page and write a byte?

maychang

Shenzhen Xiaohua published on 2021-7-10 10:07 Thank you very much. How long does it take to erase a page and write a byte?

Read your CORTEXT M0+ manual carefully. It should describe how many clock cycles are required for erasing and writing.

chunyang

All FLASH erase operations are not performed by bytes, but by sectors, blocks, pages, and the entire chip can also be erased. The erase operation takes time, and its essence is to write logic 1. As for the programming operation, it writes logic 0 into the storage bit, and logic 1 is actually not operated. The reason for this is determined by the circuit structure of the FLASH storage unit. You can find a typical FLASH unit circuit to take a look.

深圳小花

chunyang posted on 2021-7-11 23:23 All FLASH erase operations are not performed by bytes, but by sectors, blocks, and pages. The entire chip can also be erased. When the erase operation is required...

Thank you so much.

Do you mean that when writing, it is written individually by bytes, and when erasing, it is not erased individually by bytes, but the entire sector, block, or page is erased?

chunyang

Shenzhen Xiaohua published on 2021-7-12 06:30 Thank you very much. You mean that when writing, it is written individually by byte, and when erasing, it is not erased individually by byte, but the entire sector, the entire...

It has been made very clear before.

freebsder

One time wipe, the device determines it.