View Full Version : Spark Fun Logomatic SD Data Logger

phil kenny
04-21-2007, 04:54 AM
Has anyone successfully interfaced a Basic Stamp to the Logomatic Serial
SD Data Logger from Spark Fun Electronics?


Documentation for this device is found at:


On the surface it seems as if it should be an easy task.

The only input to the Logomatic is a serial data stream.

The Basic Stamp program I tried to get to work is attached, along with
the Logomatic configuration file, LOGCON.txt..

Bad connections have been ruled out by using an Ohmmeter to
verify continuity. I've tried several different variations including
a different Stamp output pin, lower baud rates, etc. but with no
success. The log file, LOG0.txt keeps showing zero bytes.

Any suggestions?.

PJ Allen
04-21-2007, 05:42 AM
Is that your actual programme? You're missing a Stamp Directive at the top as well as a PBASIC Directive.

Take a look at PBASIC Help for SEROUT and SERIN. You have T9600 as a CON, but that's PBASIC for a BS1. As you have the CASE...SELECT for BS2 variants, I assume you want a BS2-type Baudmode (??):

http://forums.parallax.com/attachment.php?attachmentid=74005NOTE: For "open" baudmodes used in networking, add 32768 ($8000) to the values from the table above. If the dedicated serial port (Tpin = 16) is used the data is inverted and driven regardless of the baudmode setting.

mk:@MSITStore:C:\Program%20Files\Parallax%20Inc\St amp%20Editor%20v2.2\PBASIC.chm::/graphics/bsxp_inline.gif


Post Edited (PJ Allen) : 4/21/2007 12:07:13 AM GMT

phil kenny
04-21-2007, 06:28 AM
That wasn't my 'actual' BS2 program. I did a cut and paste to omit a lot of
extra comments. The actual program has these directives:

' {$STAMP BS2}
' {$PBASIC 2.5}

One other casualty of the cut and paste was the omission of the #ENDSELECT
statement. It was in the actual code.

Attached is the actual code with these missing sections in place

One of the variations I tried was using the explicit BS2 9600 baud parameter, 84,
in the SEROUT statement.

PJ Allen
04-21-2007, 07:12 AM
Reviewing the Logomatic PDF. It's a 3.3V device -- and I wonder whether it can be directly interfaced with a Stamp (a 5V, TTL, device.) I think that you need a transition stage (converter) between the two.

I should probably beat it, as you were interested more in somebody who's actually got this running.

Post Edited (PJ Allen) : 4/21/2007 12:16:48 AM GMT

phil kenny
04-21-2007, 07:21 AM
Thanks for pointing this out. No mention in their data sheet about this 'feature'.

Looking more carefully at the schematic, the RX and TX inputs do indeed go
into a 3.3 volt powered device. I bet that's why is doesn't like being connected
directly to a Stamp. :-(

I'll insert a level shifter in the RX line and see if that helps.