gnupic: Need EE/Flash ROM recommendation
Subject:
Re: Need EE/Flash ROM recommendation
From:
####@####.####
Date:
4 Nov 2004 12:55:53 +0000
Message-Id:
David McNab wrote:
> > The situation is that my project is calling for playing audio samples.
> > The need is for a fair amount of reasonable quality audio (say, 32k
> > frames/sec @ 8 bits/frame stereo), which calls for a high-capacity ROM -
> > say, 4-16Mbit or more.
> >
> > My idea is to create a bunch of audio samples, including voice, sound
> > fx, bits of music etc, and burn them into a ROM
> >
> > Then, to run pins from the PIC into chained serial/parallel shift
> > registers, through to the ROM's address bus. Then, from the ROM's data
> > bus to a DAC, and out to an audio amp.
> >
> > Question - can anyone recommend a good chip to use with the PIC?
> > Am I taking a hard road here - is there an easier solution (such as
> > 'sample playing' chips with inbuilt DACs and an easy h/w interface?
>
Well obviously you want to keep the costs 'relative' to the pic, if the
sound is just an extra to the 'pic project', and not 'the pic is an extra
to the orchestra' .
When one has been working intensely on a project, it's often difficult
to realise that stuff is not obvious to others - leads to disasterous
hand-books written by the developer.
I'll try to show where/why I lose your description:-
Audio-out <--DAC <-- ROMdata8BitWide.
So you want to adr. the ROM sequentially -- or in the 'pattern/seqence'
in which it was written.
So you need to generate the par. adr-lines.
How will you do this with "chained serial/parallel shift registers" ?
> -----
> tswhite wrote:
> Dont know if this is applicable. Ideas in the past I have seen include using
> a CDROM drive. Inteface the rom drive and have a pre-burnt CD with
> all your sounds on it. Think it was in an Elektor Electronics mag.
>
I think he wants to make a 'pic sized' project.
-----
> Julian wrote:
> How about the ISD2560P chip? Havn't used it myself but sounds like what
> you are looking for.
>
An appropriately pic-sized-project is a mouse.
If you get to LSI then piccable is irelevant ?
-----
> Josef wrote:
> I don't know if any compression is acceptable, if yes, then there are
> dedicated MP3 chips, which include decoder + D/A converter. Compression
> will lower your memory requirement too. VS1001K is probably most popular
> and readily available. The data can be stored on multimedia card (MMC),
> which has serial SPI interface and is quite easy to work with. Check out
> http://www.vitrum.cz/snail/eng/mp3sale.htm for a selection of MP3 chips.
Perhaps these are made in sufficiently big quantities now ?
I still haven't found out the IO format for the flash-mem of my
digital voice recorder.
??? OH I see EE/Flash ROM is not like old fashion random access !!
Is it accessed serially ? And the data - serial too ?
Then what is the serial/parallel shift registers for: to feed the DAC ?
== Chris Glur.
