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A better quality ISD (Winbond) chip..anything new ?

Clifford said:
Have you experienced temperature dependent failures with the ISD chips?

Funny you should mention that - In one particular room I have over a
dozen units and the only one that has ever given any problems (a couple
of failures in 4 years) is right under a spotlight. What I find weird
is that in battery powered locations, they speed up at the end of
battery life (squeech!).
M
 
Succinct answer: I hate ISD too. There is cause enough for this merely
in their (unstated) datasheet errata, let alone the actual chip specs.

I've been asked recently to do some similar projects (vending machine
applications, mostly). I've chosen to use an SD card (in MMC/SPI mode)
to store raw PCM samples. I use an Atmel ATmega8 with an R-2R on one of
the ports to do the DACing. Using a parallel 16-bit DAC seems to be an
intractable problem on an 8-bit micro because of the impossibility of
updating both bytes at the same time.

I've found the Mega8 fast enough that you can bit-bang your 16 bit
samples out fast enough into a PCM56P (must try out some of those new
tiny serial DACs that AD and Maxim are putting out these days). The ISD
data sheets are a masterpiece of misdirection but at least they
basically work, unlike the Invox clones that came out a few years ago
(then vanished). The CS4231/AD1848 codec chips do 16 bit mono, stereo
etc and have a byte wide interface (have used these in combination with
30 pin SIMMS for digital delays etc).
M
M
 
M

Mike Harrison

Jan 1, 1970
0
Look at digital audio DACs - they are very very cheap, and have all the filtering etc. Can often be
driven from an SPI port. You can often take liberties with the audio interface timing - as long as
the LRCLK is synced to MCLK (use the same clock as the micro), and you give them enough sclk pulses
in each phase of LRCLK , they will usually behave.
 
J

Joerg

Jan 1, 1970
0
Hello John,
Not in UK, and we have bigger gallons. Are those figures average, and do
you do a lot of journeys over 20 miles?

Those are average. Every time I gas up I reset the 2nd trip meter and
you can pretty much divide the number of miles on there by 25 to arrive
at how many gallons will fit into the tank.

Most trips are under 20 miles, in a more or less rural setting.

Regards, Joerg
 
C

Clifford Heath

Jan 1, 1970
0
Funny you should mention that...

Ok, interesting. I've never used a Winbond chip, but a buddy of
mine is going through hell with an ISD audio chip at present.
 
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