<s>
DataFlash	B-General_Concept
is	O
a	O
low	O
pin-count	O
serial	B-Protocol
interface	I-Protocol
for	O
flash	B-Device
memory	I-Device
.	O
</s>
<s>
It	O
was	O
developed	O
as	O
an	O
Atmel	O
proprietary	O
interface	O
,	O
compatible	O
with	O
the	O
SPI	B-Architecture
standard	I-Architecture
.	O
</s>
<s>
In	O
October	O
2012	O
,	O
the	O
AT45	B-General_Concept
series	O
DataFlash	B-General_Concept
product	O
lines	O
,	O
related	O
intellectual	O
property	O
,	O
and	O
supporting	O
employee	O
teams	O
were	O
purchased	O
by	O
Adesto	O
Technologies	O
.	O
</s>
<s>
Information	O
is	O
written	O
and	O
read	O
from	O
a	O
DataFlash	B-General_Concept
device	O
using	O
any	O
microcontroller	O
,	O
such	O
as	O
the	O
Atmel	B-Architecture
AVR	I-Architecture
,	O
the	O
Microchip	B-Architecture
PIC	I-Architecture
or	O
the	O
ARM	B-Architecture
.	O
</s>
<s>
The	O
boot	O
ROM	O
of	O
numerous	O
Atmel	O
ARM	B-Architecture
microcontrollers	O
support	O
downloading	O
code	O
from	O
DataFlash	B-General_Concept
chips	O
after	O
reset	O
.	O
</s>
<s>
The	O
AT45DB161D	O
Integrated	O
circuit	O
(	O
chip	O
)	O
is	O
an	O
example	O
of	O
a	O
2	O
MB	O
(	O
16	O
Mbit	O
)	O
dataflash	B-General_Concept
product	O
.	O
</s>
<s>
This	O
comes	O
in	O
a	O
8x5	O
mm	O
small	B-Algorithm
outline	I-Algorithm
integrated	I-Algorithm
circuit	I-Algorithm
8-pin	O
package	O
.	O
</s>
<s>
The	O
AT45DCB008D	O
card	O
is	O
an	O
8	O
MB	O
(	O
64	O
Mbit	O
)	O
flash	B-Device
memory	I-Device
card	O
,	O
which	O
could	O
be	O
mistaken	O
for	O
an	O
MMC	O
or	O
SD	O
card	O
.	O
</s>
<s>
This	O
DataFlash	B-General_Concept
card	O
packages	O
an	O
AT45DB642D	O
flash	B-Device
chip	I-Device
,	O
which	O
is	O
also	O
available	O
in	O
8x6	O
mm	O
CASON	O
8-pin	O
packages	O
.	O
</s>
<s>
The	O
AT26	O
series	O
DataFlash	B-General_Concept
chips	O
are	O
software-incompatible	O
with	O
the	O
original	O
AT45	B-General_Concept
series	O
chips	O
.	O
</s>
<s>
They	O
use	O
a	O
simpler	O
command	O
set	O
,	O
supported	O
by	O
other	O
vendors	O
of	O
serial	O
flash	O
but	O
omitting	O
SRAM	O
buffers	O
and	O
other	O
features	O
that	O
make	O
AT45	B-General_Concept
chips	O
simpler	O
to	O
support	O
.	O
</s>
<s>
Both	O
DataFlash	B-General_Concept
and	O
EEPROM	B-General_Concept
chips	O
can	O
be	O
accessed	O
from	O
a	O
microcontroller	O
,	O
using	O
a	O
4-wire	O
Serial	B-Architecture
Peripheral	I-Architecture
Interface	I-Architecture
Bus	I-Architecture
(	O
SPI	B-Architecture
bus	I-Architecture
)	O
.	O
</s>
<s>
The	O
protocol	O
interfaces	O
are	O
very	O
similar	O
;	O
in	O
both	O
cases	O
,	O
bytes	B-Application
are	O
written	O
or	O
read	O
,	O
via	O
SPI	O
,	O
one	O
or	O
more	O
bytes	B-Application
at	O
a	O
time	O
.	O
</s>
<s>
DataFlash	B-General_Concept
usually	O
had	O
higher	O
capacities	O
than	O
EEPROM	B-General_Concept
in	O
the	O
early	O
days	O
,	O
and	O
it	O
still	O
provides	O
faster	O
access	O
times	O
.	O
</s>
<s>
DataFlash	B-General_Concept
capacities	O
in	O
small	O
packages	O
range	O
from	O
128	O
kB	O
to	O
8	O
MB	O
,	O
while	O
SPI	O
EEPROM	B-General_Concept
capacities	O
in	O
similar	O
packages	O
range	O
from	O
1	O
kB	O
to	O
8	O
MB	O
.	O
</s>
<s>
Flash	B-Device
chips	I-Device
are	O
tuned	O
for	O
page	O
access	O
,	O
rather	O
than	O
the	O
byte	B-Application
access	O
used	O
with	O
EEPROM	B-General_Concept
.	O
</s>
<s>
However	O
,	O
AT45	B-General_Concept
series	O
chips	O
have	O
commands	O
that	O
let	O
their	O
drivers	O
act	O
more	O
like	O
EEPROM	B-General_Concept
drivers	O
.	O
</s>
<s>
Leveraging	O
the	O
SRAM	O
buffers	O
exposed	O
by	O
AT45	B-General_Concept
chips	O
to	O
do	O
more	O
than	O
support	O
EEPROM-like	O
access	O
requires	O
specialized	O
software	O
.	O
</s>
<s>
DataFlash	B-General_Concept
cards	O
are	O
more	O
expensive	O
than	O
the	O
consumer	O
oriented	O
MMC	O
or	O
SD	O
cards	O
,	O
and	O
have	O
lower	O
capacities	O
,	O
but	O
have	O
an	O
extremely	O
simple	O
programming	O
interface	O
compared	O
to	O
MMC/SD	O
.	O
</s>
<s>
In	O
summary	O
,	O
DataFlash	B-General_Concept
enables	O
use	O
of	O
more	O
data	O
storage	O
and	O
faster	O
access	O
times	O
than	O
EEPROM	B-General_Concept
.	O
</s>
<s>
DataFlash	B-General_Concept
chips	O
can	O
leverage	O
the	O
AT45	B-General_Concept
SRAM	O
buffers	O
.	O
</s>
<s>
EEPROMs	B-General_Concept
,	O
AT26	O
series	O
chips	O
,	O
or	O
MMC/SD	O
cards	O
permit	O
use	O
of	O
second	O
sources	O
for	O
parts	O
.	O
</s>
<s>
For	O
cards	O
used	O
in	O
field	O
upgrades	O
,	O
DataFlash	B-General_Concept
cards	O
permit	O
simple	O
software	O
support	O
and	O
compatibility	O
with	O
on-board	O
flash	B-Device
chips	I-Device
;	O
MMC/SD	O
costs	O
less	O
.	O
</s>
<s>
The	O
programming	O
code	O
required	O
to	O
interface	O
EEPROM	B-General_Concept
to	O
the	O
DataFlash	B-General_Concept
chip	O
is	O
simpler	O
.	O
</s>
<s>
Examples	O
of	O
source	O
code	O
in	O
the	O
C	B-Language
programming	I-Language
language	I-Language
are	O
available	O
for	O
operating	O
systems	O
such	O
as	O
BeRTOS	B-Operating_System
,	O
and	O
eCos	B-Operating_System
.	O
</s>
