Sunday, April 6, 2008

[oopic] Re: oSerialL - Really confused

Richard,

Here is the code:

// Simple test for serial mode

oSerialL MP3 = New oSerialL;

// Init Values

MP3.IOLineS = 31;
MP3.Baud = cv9600;

Void main(Void){

ooPIC.Delay = 100;

MP3.Value = 1;

ooPIC.Delay = 5000;

MP3.Value = 181;

}


According to the MP3 player docs, in the serial mode, it should be
waiting for single byte commands. Byte values of 1 to 180 select
track 1 to 180. If the byte value is 181, it should stop playing. I
am providing power to the MP3 player directly from the ooPIC-R (using
the +5 and G pins next to pin 31.

thanks

--- In oopic@yahoogroups.com, "rtstofer" <rstofer@...> wrote:
>
>
> The Tx pin (Serial Header Pin 2) should idle high. You can see this
> in Figure 16-4 of the datasheet. The Rx pin would be pulled up by
> the Tx output of whatever is driving it. This Rx pin is 5V tolerant
> so the OOPic output should be acceptable.
>
> The OOPic Tx output would connect to the MP3 player Rx input. There
> would also need to be a common ground.
>
> Maybe you should post your code.
>
> In any event, the signals are at logic levels, NOT RS232 levels. If
> you wanted to use a PC to test your board, you would need a level
> shifter. I recommend the http://www.pololu.com/catalog/product/126?
> tab=pictures because it can connect to 3.3V power and interface
> perfectly with 3.3V or 5.0V systems. I would connect it to the 3.3V
> output from the MP3 board and ground, of course. The Tx output
> from the adapter would connect to the Rx input on the MP3 board
> (serial pin 1).
>
> Richard
>
>
>
> --- In oopic@yahoogroups.com, Andrew Porrett <slicerwizard@> wrote:
> >
> > You're seeing a positive voltage while the player is sending stop
> > bits (zeroes)?
> >
> > That's not a TTL signal...
> >
> > At 10:56 PM 4/5/2008, design.wonk wrote:
> >
> > > I am sending TTL level signals - which is what I assumed were
> > >required as there is just a single TX and a single RX pin on the
> > >player. When powered up, the TX pin shows +3V, the RX pin shows
> +0V.
> > > Although the DOCs for the player refer to it as an RS232 style
> port:
> > >
> > >Serial Modes
> > >The following two modes use an rs232 style serial port. The port is
> > >set up for 9600 baud, 8N1
> > >format. You may or may not need inverters and drivers depending on
> > >your system configuration. A Basic Stamp, a PIC an AVR, or almost
> any
> > >other micro can communicate
> > >over this kind of link.
> > >
> > >
> > >--- In oopic@yahoogroups.com, Andrew Porrett <slicerwizard@> wrote:
> > > >
> > > > Does the player expect TTL level signals or true RS232 levels?
> What
> > > > are you sending?
> > > >
> > > > At 04:43 PM 4/5/2008, design.wonk wrote:
> > > >
> > > > >I only have to send. I am trying to control a Daisy MP3
> player (open
> > > > >source kit from Make Magazine) with the ooPIC using the
> Daisy's Simple
> > > > >Serial Mode
> >
>

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