20X2 Serial out RS232 or TTL Levels ????

A

andyquirot

Member
Hi all could some body tell me weather the serout is rs232 levels or ttl levels as i cant get it to talk to my sparkfun mp3 trigger board Regards Andy Quirot
 
M

MPep

Senior Member
The output is at whatever the supply voltage is. i.e if you supply at 5V, then the output is 5V swing.
So to answer your question, definitely NOT RS232 levels. You would need a MAX232 or the like to do that for you.
 
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M

MartinM57

Moderator
...but it doesn't look like the sparkfun mp3 trigger board requires RS232 levels, so there's probably another problem.

Schematics, code, pictures etc will no doubt find the problem, otherwise we're all guessing...
 
hippy

hippy

Ex-Staff (retired)
And don't forget polarity, and, if using Txxxx, set the output high some time before sending.
 
D

Dippy

Moderator
Andy, basically they are TTL levels, but as said by Mpep, the actual voltage level is nearasdammit the V+ supply voltage you have applied to PICAXE.

What are the levels required by the MP3 device?
If it requires 3V and your PICAXE is at 5V then, unless the device is protected, you must use a couple of Rs for level shifting for Serout.

If you need help then, as said by Martin, provide details and any relevant links.
Crystal Balls are on standby over Easter and we can't see over your shoulder.
 
L

lanternfish

Senior Member
Hi Andy. Assuming you have the MP3 Trigger manual (pdf), go to pg 3

The MP3 Trigger comes with a full duplex 3.3-5V serial TTL interface ... any serial interface that uses the format: 38.4Kbps, 8-bits, 1-start, 1-stop, no parity, flow control = none. ...
Click to expand...
I'm not sure if the serial 'header' pads are labelled so that Rx is input and Tx is output, or vice-versa.
 
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