Re: OTP Secure Digital ?

"larwe" <zwsdotcom@xxxxxxxxx> wrote in message
news:1170195799.076196.75400@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Jan 30, 5:20 pm, "Talal Itani" <tit...@xxxxxxxxxxx> wrote:
I am looking for SD (Secure Digital) memory that can be programmed only
once. Basically, once programmed, it cannot be erased. I searched the
web,

There is no such thing.

Mass-produced removable memories like this tend to use mask ROM. If
they resemble SD it's only cosmetically. Such devices have a vested
interest in NOT using a simple-to-duplicate storage format where blank
media are available off the shelf.


The CSD register of the SD interface contains a write-once bit called
PERM_WRITE_PROTECT that does the follow (quoting)
"Permanently protects the entire card content against overwriting or erasing
(all write and erase
commands for this card are permanently disabled). The default value is 0,
i.e. not permanently write
protected."

Peter


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