Hello,
I want to mod a sega saturn to output spdif, i need it for my dac + amp + speaker combo. The saturn provide an i2s signal with a master clock, so it shouldn't be very hard to do...
There is a known mod that can be done to do it, most people use a basic CS8406 board to do it.
As i had to make an order at audiophonics, i bought this i2s to spdif interface :
Digitale Interface I2S vers SPDIF BNC WM8804 - Audiophonics
This thing has a terminal block for a 5v DC plus the i2s input. Strangely there is a DATA 1 and DATA 2 on the i2s input, i don't know why.
My saturn is a model 2 japanese with a TDA1386T dac. I get the 5v DC from the pin 9 - 10, i check with a multimeter and it's fine. For the i2s signal i connect this way :
MCK to pin pin 12 (sysclk)
BCK to pin 4 BCK
LE to pin 5 (word select input)
DATA to pin 6 DATA (i2s Data)
For the GRD, two cable connected to the pin 9 (digital ground) go the the i2s grd connector and DC terminal block ( - in the photo).
The spdif kit power on, tension is good on the dc terminal. I connect it with toslkink and there is light, but no sound. I check the tension in the i2s input, i get between 3.2v and 1.7v depending on the input, so there is no problem with the connection.
I hate these chinese board because audiophonics do not give a s*** to give correct technical information and the technical service don't know much better. I have problem in the past and now it's the same story, i won't even ask audiophonics it's a pure waste of time, and every info i could find on these board are of course in chinese.
This board has a i2s input and output, plus 2x spdif output (toslink and rca / bnc). I start to think there is a way to choose between the i2s output and spdif outputs. I check the tension on the i2s output and there is the same voltage as the i2s input, so the i2s out is active. There is no sign of jumper in the front of the board, but in the backside there is an IC close to the i2s input, and two resistor (R20 R21) that can be put in different position.
https://zupimages.net/up/20/32/5idx.jpg
Any idea ?
I want to mod a sega saturn to output spdif, i need it for my dac + amp + speaker combo. The saturn provide an i2s signal with a master clock, so it shouldn't be very hard to do...
There is a known mod that can be done to do it, most people use a basic CS8406 board to do it.
As i had to make an order at audiophonics, i bought this i2s to spdif interface :
Digitale Interface I2S vers SPDIF BNC WM8804 - Audiophonics
This thing has a terminal block for a 5v DC plus the i2s input. Strangely there is a DATA 1 and DATA 2 on the i2s input, i don't know why.
My saturn is a model 2 japanese with a TDA1386T dac. I get the 5v DC from the pin 9 - 10, i check with a multimeter and it's fine. For the i2s signal i connect this way :
MCK to pin pin 12 (sysclk)
BCK to pin 4 BCK
LE to pin 5 (word select input)
DATA to pin 6 DATA (i2s Data)
For the GRD, two cable connected to the pin 9 (digital ground) go the the i2s grd connector and DC terminal block ( - in the photo).
The spdif kit power on, tension is good on the dc terminal. I connect it with toslkink and there is light, but no sound. I check the tension in the i2s input, i get between 3.2v and 1.7v depending on the input, so there is no problem with the connection.
I hate these chinese board because audiophonics do not give a s*** to give correct technical information and the technical service don't know much better. I have problem in the past and now it's the same story, i won't even ask audiophonics it's a pure waste of time, and every info i could find on these board are of course in chinese.
This board has a i2s input and output, plus 2x spdif output (toslink and rca / bnc). I start to think there is a way to choose between the i2s output and spdif outputs. I check the tension on the i2s output and there is the same voltage as the i2s input, so the i2s out is active. There is no sign of jumper in the front of the board, but in the backside there is an IC close to the i2s input, and two resistor (R20 R21) that can be put in different position.
https://zupimages.net/up/20/32/5idx.jpg
Any idea ?
How its supposed to would all depend on how the CPLD is programmed.
DATA 1 and DATA 2 might be for an old digital audio format in which left and right data are on two different lines. IIUC, LE is the frame clock for non-I2S PCM digital audio (Sony verses Philips formats). It could be that the CPLD is programmed to recognize whatever valid format is connected to its inputs and convert it to I2S, SPDIF, and TOSLINK. That might be why there are I2S output pins on the board too.
Since there is no documentation, do you have a scope so you can take a look at some signals?
DATA 1 and DATA 2 might be for an old digital audio format in which left and right data are on two different lines. IIUC, LE is the frame clock for non-I2S PCM digital audio (Sony verses Philips formats). It could be that the CPLD is programmed to recognize whatever valid format is connected to its inputs and convert it to I2S, SPDIF, and TOSLINK. That might be why there are I2S output pins on the board too.
Since there is no documentation, do you have a scope so you can take a look at some signals?
Thank you for your answer. Unfortunately i have no scope...
Also i have no i2s source to try it with something different of the saturn.
Find the solution seems complicated, i start to think i will ask audiophonics for a refund and order the CS8406 board. I am very tired of audiophonics really.
Also i have no i2s source to try it with something different of the saturn.
Find the solution seems complicated, i start to think i will ask audiophonics for a refund and order the CS8406 board. I am very tired of audiophonics really.
Strictly speaking, I2S is a particular protocol. It is similar to Left Justified PCM. Then there is Right Justified PCM, which is a little trickier as it really needs to know bit-depth.
However, sometimes the whole set of them (including the Native DSD variant) are very loosely referred to as I2S.
Bit depth can be inferred from looking at clock frequencies with a scope. Sorting out the more subtle particulars can require some trial and error with settings. In some cases a cheap logic analyzer can come in handy for capturing I2C instructions used to program dac registers.
Again, for the I2C converter board everything depends on how the CPLD chip is programmed.
However, sometimes the whole set of them (including the Native DSD variant) are very loosely referred to as I2S.
Bit depth can be inferred from looking at clock frequencies with a scope. Sorting out the more subtle particulars can require some trial and error with settings. In some cases a cheap logic analyzer can come in handy for capturing I2C instructions used to program dac registers.
Again, for the I2C converter board everything depends on how the CPLD chip is programmed.
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Which is a problem because the fundamentals remain. Everything that does not conform to the laid down I2S specification is NOT I2S and calling it I2S does not change that. It just sows confusion. What's more, your widget doesn't work. As for including DSD, that borders on insanity.
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It does not matter whether or not you see it. It is what it is. It is for you to read the datasheets and understand it. It will make no moves to meet you. You have to understand this stuff as it is or it simply wll not work. There is nothing obscure about what Sega has done. The Japanese have never been big fans of I2S. The DACs come with options and the manufacturer can choose any of them. Sega have made their choice and you have to meet it. Or not. I doubt Sega care one way or the other.
You know the CS8406 works. It is for you use it or understand why it works and apply that to a different device.
That speaks to a lackadaisical attitude not uncommon to audio. Each format has a name how hard can it be to use it. Digital video seems to cope well enough with all their formats.
I don't know about that. Every field of expertise has its own technical language: Engineering, Law, Medicine, etc. Within that context shorthand is often used by practitioners who understand very well what each other are talking about. The meaning of a term may be context specific, and if the context is understood to be a physical 3-wire bus with no unique name of its own, well, some ad hoc convenient solution may work its way into the common parlance. Over time such terms may find enough usage to make their way into technical dictionaries. Or not. There are always some people who object to new terms being added, since those terms often started out as slang.
Sure. I2C and SPI are both three letters long. No lists involved.
What if I have a dac that accepts different formats on the same three pins according to its register settings. Then what if I have a digital mux selecting between two sources, one of them I2S, and the other RJ. What do I call the three wires between the mux and the dac? I2S/RJ? Now what if include DSD from the first device? Its a mouthful of letters to say or write that is often unnecessary if the context is understood.
What if I have a dac that accepts different formats on the same three pins according to its register settings. Then what if I have a digital mux selecting between two sources, one of them I2S, and the other RJ. What do I call the three wires between the mux and the dac? I2S/RJ? Now what if include DSD from the first device? Its a mouthful of letters to say or write that is often unnecessary if the context is understood.
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A red herring if ever I saw one. One would not name the traces or wires there anymore than you would seek to name the traces or wires to the LEDs or the reset circuitry. You can try and sell me the notion that calling something by its name is some onerous task but I am not buying.
More to the point, none of this gets the OP any further forward. We can debate how much of a burden it is to call something by its name, assuming one would to seek to name the thing in the first place and the OP can bemoan the doings of Sega but none of it gets us any further forward. So in that spirit....
The CS8406 in the article linked to by the OP is set to accept Right-Justified, 16-bit data with MCLK at 256Fs.
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