Interfacing the Prop with uMP3 Board

DavidM

HI,

I need to interface the ROGUE ROBOTICS uMP3 Player with the Propeller.

The uMP3 player has 5v TTL and the prop is 3.3 volt.

there is an RX & TX line from the uMP3 so I need to use 2 pins on the prop.


What is the best way to interface this, Would some series resistors do?


Thanks

Dave M

Mike Green

That's probably the easiest way to do it. A 1K resistor should work.

DavidM

Hi Mike,

You mean like this?

See attached Schematic

Dave M

Ken Peterson

@DavidM: I have a uMP3 board too. It will work at 3.3V as well as 5V. That's what I did. I imagine it's CMOS tech rather than TTL.

I had issues reading from the SD card using the file access commands. Have you tried doing that yet?

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The more I know, the more I know I don't know.· Is this what they call Wisdom?

Post Edited (Ken Peterson) : 10/29/2007 11:06:08 PM GMT

Mike Green

DavidM,
The diagram looks ok. I always get Rx and Tx mixed up since some manufacturers look at them from their device's standpoint and others look at them from the controller's standpoint. Fortunately, the 1K resistors will protect both devices from a mixup.

I've had problems reliably reading files from the memory card using a Stamp. I don't know if they fixed the firmware.

DavidM

Hi Mike,

I believe they made a firmware update for the issues with the BS2.

http://www.roguerobotics.com/files/ump3/firmware/ump3-110-12.zip


So Far I have only used the uMP3 with a computer ( a MAC via USB SERIAL ) and some AEROCOMM RF 900MHZ modems, I used ( an off the shelf) TTL to RS232 converter cable, I didn't have any issues with communications, but most I mainly sent short commands , ( not file transfers yet)

I am actually working on an UMP3 to PROPELLER ADAPTOR BOARD which has VU LED outputs to run on a membrane panel.

See attached PDF ( note its note finished yet!)

regards


Dave M