Vmusic2 5 V savvy?

[Erik van Gerven]

I bought a Vmusic2 a long time ago and got it running on the serial cable. I didn't complete managing it using the picaxe and it went into the closet because of time constraints :

Now I want to fire up this project to make a MP3 player with (oled?) display to connect to the main room stereo.

I noticed the 05m had some problems reading data from the Vmusic and I built a 3.3 to 5v converter to deal with it.

Now I want to use a 28M2 wich can run from 3.3 v so I wont have troubles reading/writing the Vmusic and then need a levelshifter to drive the display. Or can I run the OLED display on 3v3?


The treads in this forum never mention the 3v3 issue as far as I found... Can anyone confirm the correct functioning of the Vmusic on 5V and the connected picaxe running on 5V also?

 

[nick12ab]

The OLED datasheet says the OLED Module will operate down to 3.0V so the OLED will work on 3.3V.

 

[srnet]

The AXE133Y OLED does work at 3V.

My Morse decoder was on the bench, I had it running at 5V, the NE567 tone decoder needs this to work properly, but I just turned down the supply.

The OLED initialises and dispalys its welcome message down to 2.2V, although the rest of the circuit does not work.

The 08M2 manages to write to the OLED down to 2.5V.

 

[westaust55]

I noticed the 05m had some problems reading data from the Vmusic and I built a 3.3 to 5v converter to deal with it.

Now I want to use a 28M2 wich can run from 3.3 v so I wont have troubles reading/writing the Vmusic . . . .


Can anyone confirm the correct functioning of the Vmusic on 5V

Are you trying to use 3.3 Volts in the believe that is the voltage requried by the Vmusic2 module?

The Vmusic datasheet on the Rev Ed website in section 1.2 "Features" states:
- Single 5V supply input.

Section 2.1 for the Vmusic pinout indicates
- pin3 as 5V0 = 5 Volts.
- the pin at 3V3 is an output from a regulator within the Vmusic2 module.

 

[Erik van Gerven]

Westtaust,

Correct, I studied the schematic of the vmusic and l learned ALL internal electronics (except for the USB connector) is working on the internal 3V3 regulator. All I/O form this module is working on 3V3, not 5V0. I don't know if they can stand 5V0 or te picaxe recognises 3V3 as high.

I will move over to 3V3 completely since ppl above confirmed the OLED working fine on 3V3 wich solves my problem.

Only need a 3V3 I2C RAM to store the ID tags coming from the mp3 player.

 

[Erik van Gerven]

Running on 3v3 completely means in this case powering the vmusic at 5v0 (it will effectively run on the internal 3v3) and running the picaxe and RAM chip on a separate 3v3 regulator. positive sideeffect here is the 'digital' part is separated from the 'analog' part.

This way no levelshifters are needed. Only some time to get the 3v3 regulator here since they are not in my regular stock

 

[hippy]

I studied the schematic of the vmusic and l learned ALL internal electronics (except for the USB connector) is working on the internal 3V3 regulator. All I/O form this module is working on 3V3, not 5V0. I don't know if they can stand 5V0 or te picaxe recognises 3V3 as high.

It does seem from the schematic that the VMUSIC2 controller (VNC1L) runs at 3V3 but the FTDI datasheet shows it interfaced to a PICmicro running at 5V ( page 8 ) so it would be reasonable to take that to mean the I/O were 5V tolerant and that's also documented as such with other VNC1L information.

There shouldn't therefore be any problems using the VMUSIC2 with a PICAXE at 5V ... providing TTL inputs are used to read TXD and RTS#; ST inputs require 4V to be seen as high when using a 5V supply which 3V3 won't reach.

 

[Erik van Gerven]

The schematics I found for the Vmusic2 show all internal electronics except for the USB connector are powered by the internal 3v3 regulator.

According to the specs the chip inputs are 5v safe but the outputs only give 3v3.
So, to read data from the vmusic I need a levelshifter for the rts and tx outputs because I want to read the mp3 id tags

I tried to upload the schematics but that didn't work.
http://www.ftdichip.com/Support/Documents/Schematics/VNC1/VMUSIC2 Schematic Prints.pdf

 

[hippy]

According to the specs the chip inputs are 5v safe but the outputs only give 3v3.
So, to read data from the vmusic I need a levelshifter for the rts and tx outputs because I want to read the mp3 id tags

No; see post #7. You need to use TTL PICAXE inputs which recognise 3V3 as high levels when the PICAXE is run from 5V.

http://www.picaxeforum.co.uk/showthread.php?8609-PICAXE-Input-Pin-Types

TTL ( Vsupply > 4.5V )

Vih : >= 2.0V
Vil : <= 0.8V

Schmitt Trigger (ST)

Vih : >= 0.8 * Vsupply ( >= 4V @ 5V )
Vil : <= 0.2 * Vsupply ( <= 1V @ 5V )