Smart Card Memory Organization

72sonett

I am looking at the Parallax Smart Card Reader and the IS24C16A Smart Card.
Under 'Overview' it says;

The IS24C16A Smart Card provides 2 KB of serial EEPROM

I understand '2 KB' to be 2 kilobytes (should be written as kB) or 2048 bytes.

Under 'Details' it says;

Memory Organization: 2048 x 8 bits, in eight 16-byte pages

since 8 bits = 1 byte this would be 2048 bytes, which matches with the previous '2KB',

but how do I fit 2048 bytes in only 8 pages @ 16 bytes (=128 bytes)? Should that not be 8x256-byte pages, or 128x16-byte pages?

Sapphire

There are 8 blocks of 256 bytes (8x256=2048) but you can only write in 16 byte increments (pages).

See page 3 of the datasheet: http://www.parallax.com/sites/default/files/downloads/32322-IS24C16A-Datasheet.pdf

72sonett

Sapphire wrote: »

There are 8 blocks of 256 bytes (8x256=2048)

That makes more sense... thanks.

you can only write in 16 byte increments

On page 7 of the data sheet it says there is both a Byte Write and a 16-byte Page Write mode.

Sapphire

Yes, you can write either bytes or pages (16-bytes). I think that's where the confusion on the product description came from: mixing up blocks and pages.