You all might get a kick out of this little gizmo I'm starting to sell fr=
om
a friend in Germany:

It adapts I2C to RS232 signals and really makes it easy to talk to I2C
devices from just about anything. Use it as a low cost I2C analyzer or a
test unit or to make development with I2C stuff a little easier (not that
it's hard) or just to make your laptop speak direct I2C so you can hook u=
p
neat chips.

What I think is REALLY cool about the design is that the PCB can be broke=
n
several different ways to make different things:

1. The DB9 connector and MAX232 can be busted off for a RS232 level
converter. (top of the board in the picture)

2. A power connector, 7805 and etc.. Can be busted off as a separate powe=
r
supply (right side)

3. There is a small prototype area (upper right)

4. The microcontroller (an Ubicom SX) and its support circuits can be
separated (lower left) if you just want a smaller TTL serial to I2C for y=
our
own device.

The major functions are:

I=B2C Bus Master: The RS-232 / I=B2C-Adapter acts as an I=B2C master, and=
 can
perform the most frequently used read/write operations via the bus withou=
t
the need for the application software to handle the I=B2C protocol. When =
the
application sends one of the "macro command sequences", the adapter takes
care of generating the start condition, transmitting the address plus the
R/W bit, transmitting/receiving data bytes plus setting/reading the
acknowledge bit, and finally generating the stop condition. All of this i=
s
transparent to the application software. Results up to 16 bytes long can =
be
returned along with a status letter to indicate errors or a successful
reply.=20

I=B2C low-level: To ensure compatibility, the adapter also allows the
application software to directly "talk" to the I=B2C bus in order to allo=
w
communications with I=B2C devices that require non-standard sequences. Us=
ing
these "low-level commands" any number of data bytes can be transferred to=
 or
from the I2C device.=20

I=B2C Monitor: In its Monitor mode, the module acts as an I=B2C "spy", i.=
e. it
passively monitors an I=B2C bus, and sends the byte data transferred via =
the
bus together with the information, and if there was an acknowledge, or no=
t
via RS-232. An internal 32-byte FIFO buffer, together with an 115.2 kBaud
RS-232 rate allows for I=B2C bus rates of up to 100 kBit/s to be monitore=
d.=20

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3D7549794053
or
http://techref.massmind.org/techref/ubicom/rsi2o3i2c/version3_2.htm

---
James Newton, massmind.org Knowledge Archiver=20
james@massmind.org 1-619-652-0593 fax:1-208-279-8767=20
All the engineering secrets worth knowing:
http://techref.massmind.org What do YOU know?



--=20
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