Multichannel Tone Boards

I plan to use 3 tone board 2’s to create a multichannel system. I wish to integrate this with a vim3 to do DSP for this system. I believe the output of the VIM3 can handle i2s 8 channels, I wonder how as GPIO only indicated 1 pin for data(?). If it is not possible to do directly off the board would something like the MCHStreamer Kit from miniDSP be required?

As for jitter and DAC syncing if they are all using the VIM3 i2s master clock and seperate data line I believe the delay between the 3 dacs should be limited due to the TB2 having very accurate clocks, would this be true?

Thanks for any help :slight_smile:

Hello @djt540

@Eric68 will help you then.

A quick followup to this after some reading. As far as I can tell the VIM3/L uses a single pin for i2s data out - with 8 channels via frame based TDM. For my project to work seamlessly each dac would need to know which channel it is to take from the correct point in the TDM signal, then they would all start processing that data at the same time (when the TDM signal MCLK signals it).

Tone2 can output 8 channels PCM and 6 channels DSD by itself,and the 1st and 2nd analog channels can output from its’ right RCA and left RCA,the other channels should be output from the expanded PCB.
And the expanded PCB which has 3 DACs can be connected to Tone2 by 30pins FPC, topology is shown below.

I can show you the definition about the 30 Pins FPC.

PIN Number PIN Name Note
1 VSYS Source for expanded PCB(5V)
2 VSYS Source for expanded PCB(5V)
3 VSYS Source for expanded PCB(5V)
4 VSYS Source for expanded PCB(5V)
5 GND Ground
6 GND Ground
7 GND Ground
8 GND Ground
9 VCC_3V3 Source for expanded PCB(3.3V)
12 GND Ground
13 MCU_I2C_SCL I2C clock
14 MCU_I2C_SDA I2C data
15 XM_BCLK I2S bit clock/DSD bit clock
16 XM_LRCK I2S L/R clock/DSD data1
17 XM_SDO2 I2S data2/DSD data3
18 GND Ground
19 XM_SDO3 I2S data3/DSD data4
20 XM_SDO4 I2S data4/DSD data5
21 XM_DSD6 DSD data6
22 GND Ground
23 PCM_DSD Indicate PCM/DSD
24 MCLK_SEL Clock select
25 POP_MUTE Pop mute
26 EXT_IO1 expand IO1
27 EXT_IO2 expand IO2
28 EXT_ENCODER_B Encoder pin
29 EXT_ENCODER_A Encoder pin
30 EXT_FUNC_KEY Key pin
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@Eric68 this is interesting, however is the expansion board available to buy - I dont see it on the shop anywhere (though it would be amazing). Or would it be the case of getting 2 more toneboard 2s and connecting them to the 1st tone board, along with syncing their i2s data and bitclocks.

Yes,we just have designed a Multi-channel PCBA for testing,and do not sell on the shop.

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Hi @Eric68 any idea when this will be releasing as I will delay my project for it.

I am not sure,I will follow up this project all the time.

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I have discussed it with PM. How about this scheme?We open the all resource about the multi-tone PCB,include hardware and MCU firmware.

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This sounds truly amazing Eric! Thank you so much :slight_smile:

Sorry to have kept you waiting, we have open source for multichannel audio modual.
You can download the related documents from here.

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Wow this is amazing, thank you so much