Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Understanding Flash memory

Status
Not open for further replies.

srobertjames

New Member
Hi. I'm trying to get started in using Flash memory (SD cards) in projects. My understanding was that flash can not be written to unless it's first erased; and that, unlike magnetic media, deleting a file from flash actually overwrites the data with 1111s. However, some experiments with a SD card reader on a PC and a drive imager show that even after deletion, the data bytes are still there, and that new files seem to overwrite them.

Can anyone clarify whether Flash is directly overwriteable, or needs an erase command first? What happens when you delete a file from a Flash memory card?

What's the best way to get started with Flash hardware in projects? Any good guides?
 
I believe what you are seeing is just the directory redirect writing. When a new block is needed for new data there is a block management decision on if and where to clear an old block to all 1's. This way time is not wasted when there are available cleared block to save data.
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top