<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; color: rgb(0, 0, 0); font-size: 14px; font-family: Calibri, sans-serif;"><div><div><div>Yep, I’m familiar with Olivier’s stuff after doing the Through Holes Clouds. I’m still having an internal battle of whether that was the right thing to do, but it’s what got me the on the path of STM32 vs WM8731.</div><div><br></div><div>I wasn’t aware of Erics board, that looks really good. I’ll have a dig through for some pointers if that’s okay with Eric? </div><div><div id="MAC_OUTLOOK_SIGNATURE"><div><div><br></div></div><div><div>Rob Spencer</div><div>gmsn.co.uk</div><div>07590 267835</div></div></div></div></div></div><div><br></div><span id="OLK_SRC_BODY_SECTION"><div style="font-family:Calibri; font-size:12pt; text-align:left; color:black; BORDER-BOTTOM: medium none; BORDER-LEFT: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 0in; PADDING-RIGHT: 0in; BORDER-TOP: #b5c4df 1pt solid; BORDER-RIGHT: medium none; PADDING-TOP: 3pt"><span style="font-weight:bold">From: </span> Synth-diy on behalf of Julian Schmidt<br><span style="font-weight:bold">Date: </span> Wednesday, 17 February 2016 09:21<br><span style="font-weight:bold">To: </span> <<a href="mailto:synth-diy@dropmix.xs4all.nl">synth-diy@dropmix.xs4all.nl</a>><br><span style="font-weight:bold">Subject: </span> Re: [sdiy] STM32 vs WM8731<br></div><div><br></div><div>
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you could also have a look at oliviers elements repository.<br>
There you'll find schematics and code for a module that uses the
stm32f4 and the WM codec.<br>
<a class="moz-txt-link-freetext" href="https://github.com/pichenettes/eurorack/tree/master/elements">https://github.com/pichenettes/eurorack/tree/master/elements</a><br>
<br>
or at erics codec board<br>
<a class="moz-txt-link-freetext" href="http://ebrombaugh.studionebula.com/synth/stm32f4_codec_v2/index.html">http://ebrombaugh.studionebula.com/synth/stm32f4_codec_v2/index.html</a><br>
<br>
<br>
<br>
<div class="moz-cite-prefix">On 17.02.2016 09:42, Rob Spencer wrote:<br>
</div>
<blockquote cite="mid:05647E7C-7E3A-4514-9B75-A89066F9210E@gmsn.co.uk" type="cite">
<div>
<div>Thanks for the advice everyone. I tried to initiate a write
to 0x00 and still no luck.</div>
<div><br>
</div>
<div>Here’s the setup I’m using at the moment:</div>
<div><br>
</div>
<div><a moz-do-not-send="true" href="https://www.dropbox.com/s/27qcwate85vuofd/2016-02-17%2008.35.57.jpg?dl=0">https://www.dropbox.com/s/27qcwate85vuofd/2016-02-17%2008.35.57.jpg?dl=0</a></div>
<div><br>
</div>
<div>It’s a homebrew Morpho shield that fits onto the top of the
Nucleo:</div>
<div><br>
</div>
<div><a moz-do-not-send="true" href="https://www.dropbox.com/s/fq1bthc74bthbct/2016-02-17%2008.36.09.jpg?dl=0">https://www.dropbox.com/s/fq1bthc74bthbct/2016-02-17%2008.36.09.jpg?dl=0</a></div>
<div><br>
</div>
<div>I’m going to do some checks around the board based on the
suggestions below.</div>
<div><br>
</div>
<div>One quick question I’ve got is around the clock speed for
the I2S MCK. In the I2S standard it mentions 2.5MHk, however
STM32CubeMX wants at least 48MHz to run at 48KHz, even more if
its running at 96KHz. Does that sound about right? It feels a
bit high and if it is I’m really into new territory here in
terms of PCB layout, but that’s the fun part, right? </div>
<div><br>
</div>
<div>Many thanks again</div>
<div>
<div id="">
<div><br>
</div>
<div>Rob Spencer</div>
<div>gmsn.co.uk</div>
<div>07590 267835</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
</div>
</div>
</div>
<div><br>
</div>
<div>On 16/02/2016 15:17, "Synth-diy on behalf of Eric Brombaugh"
<<a moz-do-not-send="true" href="mailto:synth-diy-bounces@dropmix.xs4all.nl">synth-diy-bounces@dropmix.xs4all.nl</a>
on behalf of <a moz-do-not-send="true" href="mailto:ebrombaugh1@cox.net">ebrombaugh1@cox.net</a>>
wrote:</div>
<div><br>
</div>
<blockquote id="MAC_OUTLOOK_ATTRIBUTION_BLOCKQUOTE" style="BORDER-LEFT: #b5c4df 5 solid; PADDING:0 0 0 5; MARGIN:0 0
0 5;">
<div>I've brought up a *lot* of systems with the WM8731 over the
years. </div>
<div>Getting the I2C control interface working can be a pain.</div>
<div><br>
</div>
<div>Your HAL I2C command looks right at first glance and the
schematic seems </div>
<div>OK too, so it's probably something else. One thing that you
haven't </div>
<div>described is what the physical construction approach is. On
the WM8731, </div>
<div>you'll notice that the MCLK input pin is right next to the
I2C SCL pin - </div>
<div>I've found that the I2C SCL input is *extremely* sensitive
to crosstalk </div>
<div>from the MCLK signal and if you built this on a solderless
breadboard, </div>
<div>or with flying wires from the MCU to codec then you can
easily swamp it </div>
<div>out to the point where you get no ACKs.</div>
<div><br>
</div>
<div>If you have a scope with high impedance probes, look at the
SCL input </div>
<div>pin - if you see MCLK there at a low level, it's a good bet
your WM8731 </div>
<div>can't hear the I2C bus due to the crosstalk. Reroute the
signals or put </div>
<div>a simple RC lowpass filter on the MCLK to mitigate that.</div>
<div><br>
</div>
<div>Eric</div>
<div><br>
</div>
<div><br>
</div>
<div>On 02/16/2016 01:37 AM, Rob wrote:</div>
<blockquote id="MAC_OUTLOOK_ATTRIBUTION_BLOCKQUOTE" style="BORDER-LEFT: #b5c4df 5 solid; PADDING:0 0 0 5; MARGIN:0
0 0 5;">
<div> Just continuing on the STM32 discussions…</div>
<div><br>
</div>
<div> I’ve been trying to get a Nucleo-F411RE talking to a
WM8731, but not</div>
<div> having much luck getting it to communicate over I2C</div>
<div><br>
</div>
<div> I send the following from the STM32:</div>
<div><br>
</div>
<div> WM8731Status[0] =
HAL_I2C_Master_Transmit(&hi2c1, 0x34,</div>
<div> WM8731PowerOn1, 1, 10000);</div>
<div><br>
</div>
<div> But I don’t get an Ack from the WM8731:</div>
<div><br>
</div>
<div> <a moz-do-not-send="true" href="https://www.dropbox.com/s/yhen98n17pyrqgr/Screenshot%202016-02-16%2008.22.15.png?dl=0">https://www.dropbox.com/s/yhen98n17pyrqgr/Screenshot%202016-02-16%2008.22.15.png?dl=0</a></div>
<div><br>
</div>
<div> Here’s the schematic for the WM8731 setup:</div>
<div><br>
</div>
<div> <a moz-do-not-send="true" href="https://www.dropbox.com/s/e6fkerkmf95ldzf/Screenshot%202016-02-16%2008.20.29.png?dl=0">https://www.dropbox.com/s/e6fkerkmf95ldzf/Screenshot%202016-02-16%2008.20.29.png?dl=0</a></div>
<div><br>
</div>
<div> I’m pretty sure everything on the STM32 side is setup
correctly, and I’m</div>
<div> working on the assumption that there’s not a lot to do
with the WM8731.</div>
<div> Once all the power is connected and the I2C mode and
address pins are</div>
<div> set low it should just receive I2C messages. I think the
issue might be</div>
<div> around the address, but I’ve tried all combinations I
can think of.</div>
<div><br>
</div>
<div> Any help would be much appreciated as my wife is getting
tired of me</div>
<div> shouting at the darn thing!</div>
<div><br>
</div>
<div> Many thanks in advance</div>
<div><br>
</div>
<div> Rob</div>
<div><br>
</div>
<div> gmsn.co.uk</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
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</blockquote>
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