Giro
Junior Member level 1
Hi,
Forgive me if I posted in the wrong sub-forum.
I have some SAR with I2s output, encapsulated in a device that I would like to hot rod so to use the converters at a higher rate.
The SARs are in dual mono config in a classic 1fs system (no oversampling) which makes things easier, the data / serial signals are multiplexed I believe in a subsequent IC, after which in the original design would be conveyed to various parts of the device as well as to/from the device externally.
It would simple enough to leave the device in its current state and 'tap' Bit Clock, Word Clock and Serial lines and relay these to/from a USB module via I2s. However this does nothing to increase the 'default' sample rate from 48k. I think the only way to do this would be to re-route/de-tatch existing clock/data lines and make the USB module the new master clock. Bit clock of I2s seems to be the easiest part to understand so far my assumption is it can be determined by whatever USB module can put out.
The SAR in question, which there are two of (dual mono) has a serial output (easy enough) the two aforementioned Bit Clock, Word Clock inputs and a third 'CC' input which I hope someone familiar with in these arts, can elaborate on. CC can be set either High or Low and is immediately connected to 'comparator latch gate' inside the SAR.
I'm not that all too good at the math here which the datasheet describes. Judging by the SAR datasheet, CC has something to do with integration and Sample Order Hold, the latter being external to the converter.
The Word line I imagine alternates between the the two SARS so as to maintain appropriate L/R multiplex between them (correct me if I'm wrong)
Like I say the only USB interface I've managed to track down that allows for I2S input and upto 192khz is raspberry PI which are quite cheap from I've read. I've not yet been able to find anything else and I'm open to suggestions. This project is actually for a prototype, used to demo/educate theory (I understand the operational principles well).
So anyone here intimately familiar with interfacing these signals? (I realize I2s has been superseded by I2c since forever).
I can provide the datasheet for the SAR and a schematic snapshot of the relevant area of the device, if interested...
Forgive me if I posted in the wrong sub-forum.
I have some SAR with I2s output, encapsulated in a device that I would like to hot rod so to use the converters at a higher rate.
The SARs are in dual mono config in a classic 1fs system (no oversampling) which makes things easier, the data / serial signals are multiplexed I believe in a subsequent IC, after which in the original design would be conveyed to various parts of the device as well as to/from the device externally.
It would simple enough to leave the device in its current state and 'tap' Bit Clock, Word Clock and Serial lines and relay these to/from a USB module via I2s. However this does nothing to increase the 'default' sample rate from 48k. I think the only way to do this would be to re-route/de-tatch existing clock/data lines and make the USB module the new master clock. Bit clock of I2s seems to be the easiest part to understand so far my assumption is it can be determined by whatever USB module can put out.
The SAR in question, which there are two of (dual mono) has a serial output (easy enough) the two aforementioned Bit Clock, Word Clock inputs and a third 'CC' input which I hope someone familiar with in these arts, can elaborate on. CC can be set either High or Low and is immediately connected to 'comparator latch gate' inside the SAR.
I'm not that all too good at the math here which the datasheet describes. Judging by the SAR datasheet, CC has something to do with integration and Sample Order Hold, the latter being external to the converter.
The Word line I imagine alternates between the the two SARS so as to maintain appropriate L/R multiplex between them (correct me if I'm wrong)
Like I say the only USB interface I've managed to track down that allows for I2S input and upto 192khz is raspberry PI which are quite cheap from I've read. I've not yet been able to find anything else and I'm open to suggestions. This project is actually for a prototype, used to demo/educate theory (I understand the operational principles well).
So anyone here intimately familiar with interfacing these signals? (I realize I2s has been superseded by I2c since forever).
I can provide the datasheet for the SAR and a schematic snapshot of the relevant area of the device, if interested...
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