I2S to SPDIF on XU208 Topic is solved

[Ross]

I've used the same Linux SoC for output I2S rates up to 384K; is there any reason why the XU208 couldn't handle that? The XE216 can do 384K (USB->SPDIF) with a few tweaks; I'm hoping the XU208 and my idea can do the same :)

Yes should be no issue, only stereo I assume, should be not be taxing for a 208. One core for spdif, one for i2s, one for i2c. Maybe you could add an additional core between spdif to decouple a bit.

[Zed1970]

Cheers mate!

[Zed1970]

Yeah, I'll probably start with the slimmed down USB->SPDIF I already have (which has decoupling), ditch the USB audio side and bolt up the spdif input. Thanks for your thoughts, appreciated!

[Ross]

Right, yeah that’s definitely an approach! Try setting XUA_USB_EN to 0 for a head start!

[Zed1970]

Regarding the document 'AN01027_-Porting-the-XMOS-USB-2.0-Audio-Reference-Software-onto-XU208-custom-hardware_1.0.0rc1'

There's a bunch of pins not connected warnings as pasted below.

xmap: Warning: More than 6 cores used on a tile. Ensure this is not the case on tile running XUD.
xmap: Warning: port "XS1_PORT_1F" on tile[0] is not connected to any pins in this package.
xmap: Warning: port "XS1_PORT_1G" on tile[0] is not connected to any pins in this package.
xmap: Warning: port "XS1_PORT_1E" on tile[0] is not connected to any pins in this package.
xmap: Warning: port "XS1_PORT_1H" on tile[0] is not connected to any pins in this package.
xmap: Warning: port "XS1_PORT_1J" on tile[0] is not connected to any pins in this package.
xmap: Warning: port "XS1_PORT_1K" on tile[0] is not connected to any pins in this package.
xmap: Warning: port "XS1_PORT_1I" on tile[0] is not connected to any pins in this package.
xmap: Warning: port "XS1_PORT_4A" on tile[0] is not connected to any pins in this package.

There are defined in the project's xn as
USB ports
Port Location="XS1_PORT_1H" Name="PORT_USB_TX_READYIN
Port Location="XS1_PORT_1J" Name="PORT_USB_CLK"
Port Location="XS1_PORT_1K" Name="PORT_USB_TX_READYOUT"
Port Location="XS1_PORT_1I" Name="PORT_USB_RX_READY"
Port Location="XS1_PORT_1E" Name="PORT_USB_FLAG0"
Port Location="XS1_PORT_1F" Name="PORT_USB_FLAG1"
Port Location="XS1_PORT_1G" Name="PORT_USB_FLAG2"
Port Location="XS1_PORT_8A" Name="PORT_USB_TXD"
Port Location="XS1_PORT_8B" Name="PORT_USB_RXD"

If I comment out any of these the build fails, I guessing these have to be defined to keep the code happy and are just placeholders? Any way of getting rid of them?

Cheers.

[Ross]

Don't worry about these, the ports are connected internally inside of the package/die.