Made this little WM8731 codec board

Started by cloudscapes, July 23, 2015, 12:35:38 PM

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cloudscapes

Never was satisfied with mikroelektronika's popular board, since it was mic-in headphone-out only (line in/out aren't broken out), and the master clock wasn't broken out either. Extremely limited in flexibility. The OML board looks really good but is hard to find. So I made my own.

I've ignored the microphone/headphone stuff since it's not really useful for effects. Broken out the lines, have split analog and digital ground fills, and small enough to breadboard.

Seems to be working!

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{DIY blog}
{www.dronecloud.org}

g_u_e_s_t

looks good, nice and small.  are the resistors on the SPI for level shifting?  the OML codecshield isnt discontinued, but the codecshield kits probably will be.  they are out of stock right now, and will have maybe 8 more going back up soon.

cloudscapes

Oops! Didn't know about it not being discontinued, edited my original post.

The additional resistors are force of habit 220ohm just to take the edge off. I probably don't need them anymore since there are some right on the board. The two other resistors are the pullups on the control I2C which I had forgotten.

I fried it last night by accidentally having my function gen squirt 5v through it instead of 2-3v :( I have other bare PCBs of this (oshpark boards come in threes), but I've just needed to order more codecs. Bah.
~~~~~~~~~~~~~~~~~~~~~~
{DIY blog}
{www.dronecloud.org}

g_u_e_s_t

no worries.  sparkfun stopped carrying them, so they are only through synthcube at the moment.  i found i needed a bit of resistance on the SPI lines, or there was too much crosstalk, and the right channel would get all noisey.  100ohms to 220ohms was about right, more than that and the signals would start to slow down too much.  i used 910ohm input resistors, which made it a bit more tolerant of over voltage at the input.  but diodes would probably be better.