Search found 16 matches

by sleepfox
Sun Sep 08, 2019 5:01 am
Forum: USB Audio
Topic: Migrating from XHRA to XU208
Replies: 189
Views: 1093725

Re: Migrating from XHRA to XU208

You shouldn't have any problem using 12MHz for system clock. You will need to edit the .xn file and that should be it. Refer to Sec 7 of https://www.xmos.com/download/XU208-256-TQ64-Datasheet(1.16).pdf -- the XU208 in TQ64 will boot with any clock from 9 - 25MHz. And note that the only clocks that ...
by sleepfox
Tue Aug 27, 2019 4:35 pm
Forum: USB Audio
Topic: Migrating from XHRA to XU208
Replies: 189
Views: 1093725

Re: Migrating from XHRA to XU208

Hi, instead of 24mHZ, can I use 12mHZ as system clock? Will the internal PLL be able to scale it up? If yes, what part of code should I modify accordingly? Thanks.
by sleepfox
Wed Aug 14, 2019 2:08 am
Forum: XMOS Devices
Topic: XUF208-256-TQ64 Spec
Replies: 2
Views: 3635

Re: XUF208-256-TQ64 Spec

Hi, Mon2,

Thanks. Good to know. Cheers.
by sleepfox
Mon Aug 12, 2019 6:01 pm
Forum: XMOS Devices
Topic: XUF208-256-TQ64 Spec
Replies: 2
Views: 3635

XUF208-256-TQ64 Spec

Hi, I have a quick question about the XUF208-256 spec sheet. On page 3, it says that "the device has a build in flash of 2mb". However, on page 14, it says that "the device boots from a QSPI flash (IS25LQ016B) that is embedded in the device". Now IS25LQ016B is actually 16mb. So w...
by sleepfox
Fri Aug 31, 2018 3:53 am
Forum: USB Audio
Topic: Migrating from XHRA to XU208
Replies: 189
Views: 1093725

Re: Migrating from XHRA to XU208

And like I said in post 2) of post 101. I once thought about using LT3045 only (without a power monitor IC) to monitor the power and boot sequence. Attached is the schemtics that I once drew for this idea.
by sleepfox
Fri Aug 31, 2018 3:50 am
Forum: USB Audio
Topic: Migrating from XHRA to XU208
Replies: 189
Views: 1093725

Re: Migrating from XHRA to XU208

Hi, Mon2, About the voltage divider in the schematics that you attached. The values were configured in a way that the PGFB pin senses 10% of the output voltage. This is a fast startup configuration. Instead of normal 100uA current, the chip send 2mA current to Rset (and charges its large bypass capa...
by sleepfox
Fri Aug 31, 2018 1:53 am
Forum: USB Audio
Topic: Migrating from XHRA to XU208
Replies: 189
Views: 1093725

Re: Migrating from XHRA to XU208

Hi, Mon2, Thanks for checking the schematics for me. 1) R3 is 10K ohm. The output voltage is formed by dropping 100uA constant current on this resistor. 10Kohm*100uA should gives an output voltage of 1V. R4 is 4.7ohm, as in the original XHRA schematics. It forms a RC network with a 0.1uf cap and 1V ...
by sleepfox
Tue Aug 21, 2018 9:15 pm
Forum: USB Audio
Topic: Migrating from XHRA to XU208
Replies: 189
Views: 1093725

Re: Migrating from XHRA to XU208

Hi, attached is the schematics. I am not good at creating good looking altium components and thus some parts are really messy. Has cleaned it up a bit, add a few notes and hopefully it is good now. Anyhow, it is a simplified version of XHRA usb to i2s interface. It is self-powered and its audio cloc...
by sleepfox
Tue Aug 21, 2018 12:26 pm
Forum: USB Audio
Topic: Migrating from XHRA to XU208
Replies: 189
Views: 1093725

Re: Migrating from XHRA to XU208

Hi, Mon2 and infiniteeimprobability, thank you both for the replies. Just back from a road trip. I will post the schemtic tonight. Quite messy so need to clean it up a little first. It is a very simplied version of the original XHRA usb interface though.
by sleepfox
Wed Aug 08, 2018 5:35 pm
Forum: USB Audio
Topic: Migrating from XHRA to XU208
Replies: 189
Views: 1093725

Re: Migrating from XHRA to XU208

Hi, I have almost finished the PCB and have a few hardware questions before print. 1) What is the output impedance of XMOS and what is the correct resistance to source terminate the I2S signal ouput (target characteristic impedance of 50ohm)? 33ohm? 2) I plan to use XUF208 and thus do not need to us...