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Old 22nd May 2005, 12:40 PM   #1
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Default I2S split into left & right?

Hi,

Anyone knows about a Bitstream design in the September and October 1990 issues of Hifi News? In this design the inverted L/R datastream is created by feeding the normal L/R datastream to both inputs of a two input nand gate, a 74HC132. The +L/-L and +R/-R datastreams are then created using a dual 64bit shift register (4517) and a dual 2 to 1 multiplexer (74HC157) and fed to a SAA7321 each. I will tray to build balance nonos TDA154x dac, so a copy of that article could help a lot, I guess. Thx all.
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Old 22nd May 2005, 06:07 PM   #2
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Default Re: I2S split into left & right?

Quote:
Originally posted by aparatusonitus
Hi,

Anyone knows about a Bitstream design in the September and October 1990 issues of Hifi News? In this design the inverted L/R datastream is created by feeding the normal L/R datastream to both inputs of a two input nand gate, a 74HC132. The +L/-L and +R/-R datastreams are then created using a dual 64bit shift register (4517) and a dual 2 to 1 multiplexer (74HC157) and fed to a SAA7321 each. I will tray to build balance nonos TDA154x dac, so a copy of that article could help a lot, I guess. Thx all.

I have photocopy of it somewhere but no scanner at present. I could draw the relevant schematic and let you have that but you should be aware it expects serial clock to be 32Fs.
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Old 22nd May 2005, 09:03 PM   #3
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Default Re: Re: I2S split into left & right?

Hi rfbrw,

Somehow, I am not suprised that you are gonna be the first one to replay ;-) A shematic will be fine...thx.


Quote:
Originally posted by rfbrw you should be aware it expects serial clock to be 32Fs. [/B]
[B]

How to fix that?
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Old 22nd May 2005, 11:29 PM   #4
guido is offline guido  Netherlands
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I've also made something like that. Took me a while to figure out what exactly. Long story Anyway, search in the digital section, schematics are there somewhere.

If you're target dac is 1541, there's even a pcb available.
It works, but there are improvements possible (reclock after dividing, 1541 PS arrangements and some more stuff). Going to do a version 2 someday...

edit: a HEF4517 can only be used for non-os: it's too slow otherwise.
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Old 22nd May 2005, 11:45 PM   #5
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Default Re: Re: Re: I2S split into left & right?

Quote:
Originally posted by aparatusonitus
[B]Hi rfbrw,

Somehow, I am not suprised that you are gonna be the first one to replay ;-) A shematic will be fine...thx.





How to fix that?

The schematic is attached below.

WSAB is FSYNC or LRCLK.
CLAB is SCLK or BCLK.
DAAB is SDATA.

Serial clock is 32Fs. For 64Fs use the 4562.
Attached Images
File Type: gif split.gif (8.9 KB, 5589 views)
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Old 23rd May 2005, 03:53 PM   #6
Zoran is offline Zoran  Serbia
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Yes I remember
It was before about a Year
the subject was the same...
Guido made some good version
but with the microcontroler if i
remember right
.
I think that we done some work on
decomposing the serial bus
without microcontroler supervising,
to parallel and after that again
merge to simultanious format
for TDA 1541A DAC...
.
the idea was to built the DAC not simetrical output...
.
that was based on one philips
document i think that You can find the topic...
.
anyway for that operation we need a 64 bit lenght
or 2x32 bit
because we have 2 words with 16 bit lenght...
.
16 bit L ... 16 bit R ... 16 bit L ... 16 bit R to
16 bit L ... 16 bit L ... 16 bit R ... 16 bit R

note TDA 7030 outputs to TDA 1540 dac
maybe the same format cn be used for
simultaneous data for TDA 1541A ?
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Old 23rd May 2005, 07:37 PM   #7
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Thank you very much rfbrw, you have just given me a new pair of wings.

BTW, any preferences among 74.../ABT/AC/ACT/HC/HCT/VHC/VHCT/...132/157 crowd?
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Old 23rd May 2005, 09:06 PM   #8
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Quote:
Originally posted by aparatusonitus

BTW, any preferences among 74.../ABT/AC/ACT/HC/HCT/VHC/VHCT/...132/157 crowd? [/B]

AHC or VHC (same thing, different name) is just fine.

Josip
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Old 23rd May 2005, 11:37 PM   #9
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Quote:
Originally posted by aparatusonitus
Thank you very much rfbrw, you have just given me a new pair of wings.

BTW, any preferences among 74.../ABT/AC/ACT/HC/HCT/VHC/VHCT/...132/157 crowd?

The article specifies a 74HC132 and a 74HC157.
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Old 24th May 2005, 01:25 AM   #10
guido is offline guido  Netherlands
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Quote:
Originally posted by Zoran
Yes I remember
It was before about a Year
the subject was the same...
Guido made some good version
but with the microcontroler if i
remember right
.
I think that we done some work on
decomposing the serial bus
without microcontroler supervising,
to parallel and after that again
merge to simultanious format
for TDA 1541A DAC...
.
the idea was to built the DAC not simetrical output...
.
that was based on one philips
document i think that You can find the topic...
.
anyway for that operation we need a 64 bit lenght
or 2x32 bit
because we have 2 words with 16 bit lenght...
.
16 bit L ... 16 bit R ... 16 bit L ... 16 bit R to
16 bit L ... 16 bit L ... 16 bit R ... 16 bit R

note TDA 7030 outputs to TDA 1540 dac
maybe the same format cn be used for
simultaneous data for TDA 1541A ?
Hi,

Not a microcontroller, but prog logic. I used a gal but i had some 'extra' (some were useless ) features. Also the gal code was way too complex in the beginning.

Was looking at a cpld for v2, to include DEM reclocking and some more stuff. But i got a pile of GAL's recently But working on the preamp first and an output stage (prometheus D1). Someday...

The schematic here is simpler, quite elegant. Dont go the parallel route anymore, the schematic here is i2s in to i2s out. Much easier. I certainly saved the picture.

Some thoughts

Mind you 32FS means that it wont work for 7210/7310/8412 output for building nos dacs (not shure what you're up to). That is 64FS (64 samples for one stereo 'sample', so 32 per left or right sample, so yes 16 bits used and 16 bits not used) format, so (as stated) 4562 required. I guess you can also use two 4517 daisy chained.

But keep an eye on the clockspeed! A HEF cmos chips is slow. I tried few HEF4517 and only one (philips) worked. At 64FS the clock is 'only' 2.8MHz. For higher clockspeeds (e.g. 8xOS at 32FS ~ 11MHz) you could daisychain some more (lots of...) 74 type shift registers or find a way to use the 4517 at 15V powersupply Typical speeds: 5MHz at 5V, 15MHz at 15V.

And the LSB is one bit o Oops, sorry
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