Re: TI-H: Back to basics
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Re: TI-H: Back to basics
>>And as for this MP3 player thing... Exactly what are you trying to
>>accomplish with it? First of all, as you know, you can't exactly buy
>>the MAS3507D decoder chip at rat shack.
>
>Nope. But you can buy it from Texas at $28 a chip.
Really? What place in texas? I'd be nice to have a source in the USA
:).
>>Hence the reason you were
>>bitching about calling germany, I assume :)?
>
>I gave up wit da loosers.
Ahh.
>Using the same voltage. they can both handle the same voltage. If I run
>into problems, i'll just throw in some pullup/down.
The chip lists the maximum allowable supply voltage to be 5.5 volts,
and *everywhere* else it shows the maximum recommended supply voltage
to be 3.0 < Vdd < 3.6v... Did you ask a micronas engineer whether you
can realiably run it at 5.0v? That's damn near the absolute maximum,
you can blow the I/O drivers if you have a spike or something. And if
you run at the recommended ~3.3V supply, you will then be forced to
use logic-conversion circuitry to interface to an AVR. You *cannot*
simply use a pullup or pulldown, it doesn't work that way. That is,
unless you're bryan rittmeyer, who thinks pullups and pulldowns are
the greatest thing since sliced bread :).
>>But then again, it
>>won't really matter because who DOESN'T like fuzzy static background
>>noises while they're listening to their favorite MP3 :)?
>
>Well, then maybe they should make it better. I'm posting the
>instructions/plans/schematics on the net so they can make it.
But how is the sound output on your own prototype? You never were
clear when we talked before... I've heard accounts that MPMan is 100%
perfect stereo output, but that's with a properly layed-out PCB.
>I can't use that in the released version, thats why the plans are not on
>the net yet. I'm waiting for a DAC I beleive to the specs will work.
Heh... Which DAC are you trying to interface? You're probably running
into the nasty little problem that the MAS only outputs the ~22MHz
signal synchrnized with Fs, as opposed to the ~11MHz most of them
need.
>>In case you haven't figured it out, the DAC that came with
>>the little "kit" you begged for isn't exactly mainstream.
>
>I didn't beg for any kit. I bought a $28 decoder and a $9 pre-production
>sample of the 3550A dac.
I thought you told me that you got some free samples from some guy in
california, like three of them...
>>What about
>>the oscillator source for the MAS?
>
>I can change the PLL something or other to make it work fine.
But how are you doing it now?
>>Not to
>>mention the fact that the oscillator must be at TTL levels and 5v
>>rail-to-rail oscillators will likely damange the chip.
>
>Of course it will. They don't recomend more than 3.3 for the chip... :\
Right, but you said above that you were running with a Vdd at 5.0
volts... The absolute maximum logic '1' input voltage is Vss + 0.3
volts, which means you can handle a 5.3 volt signal, but again this is
reaching towards the absolute maximum.
>>Third, about this IDE portable thing... I've gotten like 10 messages
>>from people wondering about its "features," so I'd like you to clear
>>that up...
>
>People e-mail you about me? :/
Yes, unfortunately :).
>>Or will this simply load all the mp3's sequentially and PLAY them
>>sequentially...
>
>Thats what my beta did. Remember back then? I told you in IRC I had it
>working. I need some error correction becuase by the time the data got
>from the computer to the player it was full of CRC errors... :( Oh well,
>I've re-designed the source since then.
>
>>Boy, wouldn't that be exciting :).
>
>To construct a barebones hard drive IDE player for ~$50? yes, to most it
>would be exciting. Less than the 'EII'.
After everything, it's gonna be a lot more than a paultry $50. That's
a gross underestimate. Case, power supply, batteries/battery charger,
parallel port/parallel port interface cable, LED (lcd?) display, pcb
(not cheap if you go to a fab house), avr ($10+), MAS3507D ($28+
shipping), DAC ($6+), audio output circuitry (bulk capacitors,
dual-gang potentiometer, 3.5" stereo jack, etc.), IDC 44-pin cable
(for the IDE hard drive), IC sockets, AVR programmer if user doesn't
have one yet, keypad/switches, other misc passive parts, and not to
mention at LEAST $50+ for a laptop hard drive larger than a couple
hundred megs, etc.etc.etc. Still think it's ~$50 :)?
>>I've been getting
>>(err, lately I've been deleting :) far too many emails on this,
>>especially since that f00 at mp3.com seems to love to report on your
>>latest activities :).
>
>You mean Michael Robertson...
Umm yeah, him :).
-Mel
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