Sparkfun MP3 Board Help

[andyquirot]

Hi all and a happy new year to you

I have just brought a Sparfun MP3 Trigger board with the intention of using in my models for sound fx. But i have just noteced that the serial input is 38.4Kbaud am i right in thinking the picaxe chips wont go that hi. If so dose any body have any iders how to solve this
Regards Andy Quirot

 

[hippy]

Depends on which PICAXE you have - The X2's operates at 8MHz by default with 9600 baud available via SERTXD which will be 38400 when ramped up with a SETFREQ M32. Any which have HSERSETUP will be able to generate 38400 baud. It's also possible with an 18X with a bit of fiddling with SFR's.

 

[BCJKiwi]

Was checking the manuals and they do not seem to cover any speeds higher than 19200 (unless I missed it) - perhaps another item for the next manual?

 

[andyquirot]

No shure how to do that

i looked up (HSERSETUP) in the manual and dont quite under stand. Could you make a recomedation on what chip and res i need . I want to send out

Command: Trigger (binary)
Number of bytes: 2
Command byte: ‘t’
Data byte: n = 1 to 255
Comments: If it exists, the track with the filename “TRACKNNN.MP3” will be started, where NNN is the ASCII
equivalent of the data byte n.

to play the track that i want

i know i am a bit thick i know a bit about electronics more a scale modeler sorry
Regards Andy Quirot

 

[Andrew Cowan]

BCJ: I think only Hserout lets you go higher than 19200 baud.

Andy: HSersetup is used to set the baud rate and polarity - Hserout is used to send the actual data via the hserial out pin on X1 and X2 parts. I'd use a 20X2.

Happy new year for 15 minutes time!

A

 

[BCJKiwi]

Thanks,

perhaps the Manual could note (under the serout/sertxd section) to refer to hserstup for higher speeds?

 

[hippy]

To clarify - All PICAXE's support four baud rates at 4MHz for SEROUT and SERIN ...

For 08, 08M, 18, 18A, 28 and 28A -

300
600
1200
2400

For all the others -

600
1200
2400
4800

When operating at above 4MHz, the baud rate will double for every doubling of operating frequency, so, for those which support 4800 at 4MHz, the maximum baud rates will be -

4MHz : 4800
8MHz : 9600
16MHz : 19200
32MHz : 38400
64MHz : 76800

In addition, SERTXD always uses 4800 baud at 4MHz for all PICAXE variants and will correspondingly double with a doubling of operating frequency.

While the X2's fit this model, their default operating frequency ( without any SETFREQ ) is at 8MHz rather than 4MHz.

As the maximum baud rate doubles with doubling operating frequency, so too does the minimum baud rate.

Complimentary to doubling operating frequency, halving the operating frequency halves the minimum and maximum baud rates.

Finally, the maximum operating frequency varies for each PICAXE variant which is beyond our control.

This information is given within the PICAXE Manual with the exception that baud rates are not currently explicitly listed for 32MHz and 64MHz operation and have to be extrapolated from what is listed.

 

[BCJKiwi]

Thanks for the clarification - how about this lucid explanation inthe manual in place of specificics that go part of the way in one place and alternative explanations in another place that is diffeent from another section.

Just trying to help here.
Features have been added over time and processors have been added over time. Unfortunately the manual has not kept up with information becoming increasingly fragmented.

 

[andyquirot]

Thanks

Thanks for all the comments but i dont know much about serial i was hoping sombody would say some thing like ( use a 29x and use M8 and then send data like this xxxxxxxxxxxx) but thanks any way
Regards Andy Quirot

 

[hippy]

i was hoping sombody would say some thing like ( use a 29x and use M8 and then send data like this xxxxxxxxxxxx)

Use a 20X2 ...

#Picaxe 20X2
SetFreq M32
SerOut C.0, N38400_32, ( "Happy New Year" )

Adjust pin and data to be sent to what you require. Data will be sent at 38400 baud.

 

[andyquirot]

Thank you

Thank you for that i will order some today Regards Andy Quirot