XCore Exchange

Hi infiniteimprobability,
Thank you very much for help!
You was absolutely right, I forgot to remove the I2C task for DAC. So the problem solved and my USB to I2S works perfect!

infiniteimprobability,
I could not see an option under your profile to contact you directly. I would like to discuss something with you. Will you email of PM me?

Thank you,
Dan

Brilliant idea and very helpful thread! Thanks. I think it might be a good idea to use XUF208 instead if 1MB embedded flash is enough. Cheers.

Hi, can I reassign the I2S output and MCLK input pins from X0D36~XOD39 (XUF208) to 4 pins out of XOD27~XOD33? It would make PCB routing much easier.

The datasheet says that XOD27~XOD33 are all multi-bit pins. Can they be configured as 1-bit pins as well? I suppose I2S needs 1bit output pins.

Thanks.

I can't seem to find it in the documentation (if it even exists)...is this solution capable of DSD512 streams?

I suppose this post answers my question:

http://www.xcore.com/viewtopic.php?f=26&t=6736

So it won't work on the pins that I proposed. No big deal I just need to take a detour to route the USB differential pair. Cheers.

Hi, for the USB_VBUS pin on XU208, can I simply pull it to ground through a 47K resistor and maybe a bypass cap, without connecting the VBUS from USB connector? (I will opt to go with external power supply.)

the USB power pin is known for signal pollution and I even chose to buy three-thread (D+, D-, GND) USB cable.

With this connection, will the device automatically disconnect its pull-up resistors from D+/D- pin, as required in the datasheet?

Another question, what is the typical voltage on RST_N to pull the device out of RESET? Judging from the ADM1085 used, 0.4~08V seems to be fine. If I choose to use 1V, do I need to put a resistor in between? Thanks.


BTW, this is my plan. A clean external 3.3V power supply will be applied on board and powers the i.o pins. It will also act as the input voltage for a LDO regulator to derive 1V for cores and also RST_N if that is within the appropriate range. The regulator will work only the input voltage is adequate (configured to be around 3~3.3V). And it takes about 0.1s before the output voltage ramps up to 1V, and thus allow enough time for VDD's and RESET. If it works fine, one clean external 3.3V supply and one 3.3 to 1.0 LDO regulator will makes sure the boot procedure correct. I think it is a neater solution than original. Cheers.

@sleepfox, be cautious about the use of LDO regulators for the 1v0 rail as the current draw may be in the scope of 500mA. For this reason, most designs opt for a high efficiency switching regulators and some with an internal power good status to properly time the voltage rail sequencing.

Here is a low cost switcher that is good for upto 1A (when applied with the respective support components such as the external inductor = Taiyo Yuden NR series are quite good and low cost through Digikey):

Diodes Inc # AUR9705

https://www.diodes.com/products/power-m ... rt/AUR9705

When you know for sure that your current draw will be < 200 mA then a low cost LDO such as the TCR2EF / TCR2EE series is a valid option. As these are quite tiny in size, consider to layout a PCB to support both footprints so that you can continue to build if either version is not in stock with the distributors.

Thanks. It is for 2 channel USB to I2S interface and up to 192K and therefore I am sure it will be within 200mA. I have owned a few of various interface including one with XUF216 and the currents drawn are all close to 200mA. Cheers.

Hi, I've been using the XHRA successfully in an application for a while now but now have finally implemented the XU208 into my design along with a JTAG connector.
I thought I had followed XU208 data sheet correctly when connecting a JTAG header to the device (Section G.2), but when I come to flash the device using xTIME and the XTAG3 programmer I get "Cannot load image, XCore 0 is not enabled".

I have looked at similar issues on this forum involving the JTAG programming but none of the discussions confirm what minimal connections are required for JTAG.
I am not interested in a full xSYS connectivity as I just want to flash the device.