https://osmocom.org/https://osmocom.org/favicon.ico?16647414092019-03-24T10:37:57ZOpen Source Mobile Communicationsosmo-clock-gen - Bug #3857: Use SAMD XOSC / PLL / GCLK to allow lower reference frequencieshttps://osmocom.org/issues/3857?journal_id=136202019-03-24T10:37:57Zlaforge
<ul><li><strong>Target version</strong> set to <i>hw-v2</i></li></ul> osmo-clock-gen - Bug #3857: Use SAMD XOSC / PLL / GCLK to allow lower reference frequencieshttps://osmocom.org/issues/3857?journal_id=136222019-03-24T15:51:28Zhoriz0n
<ul></ul><p>Additional information on what the clock chip can actually achieve is available at</p>
<p><a class="external" href="http://www.simonsdialogs.com/2018/11/si5351a-any-frequency-cmos-clock-generator-and-vco-specifications-myths-and-truth/">http://www.simonsdialogs.com/2018/11/si5351a-any-frequency-cmos-clock-generator-and-vco-specifications-myths-and-truth/</a><br /><a class="external" href="http://www.simonsdialogs.com/2018/11/si5351a-u-blox-m7-clock-generator-tests/">http://www.simonsdialogs.com/2018/11/si5351a-u-blox-m7-clock-generator-tests/</a></p> osmo-clock-gen - Bug #3857: Use SAMD XOSC / PLL / GCLK to allow lower reference frequencieshttps://osmocom.org/issues/3857?journal_id=138232019-04-06T16:37:01Zlaforge
<ul><li><strong>Status</strong> changed from <i>New</i> to <i>In Progress</i></li><li><strong>% Done</strong> changed from <i>0</i> to <i>10</i></li></ul><p>Most likely candidate is a ATSAMD21E18A-MUT which is in QFN-32 package (current: QFN-24) and has 256k flash and 32kBytes of RAM. It's readily available from e.g.Digikey in large volume.</p> osmo-clock-gen - Bug #3857: Use SAMD XOSC / PLL / GCLK to allow lower reference frequencieshttps://osmocom.org/issues/3857?journal_id=143972019-05-10T09:37:14Zlaforge
<ul><li><strong>Assignee</strong> changed from <i>laforge</i> to <i>mschramm</i></li></ul> osmo-clock-gen - Bug #3857: Use SAMD XOSC / PLL / GCLK to allow lower reference frequencieshttps://osmocom.org/issues/3857?journal_id=144632019-05-15T18:51:20Zmschramm
<ul><li><strong>Precedes</strong> <i><a class="issue tracker-2 status-3 priority-2 priority-default closed behind-schedule" href="/issues/3858">Feature #3858</a>: Make more GPIOs avaliable for future use</i> added</li></ul> osmo-clock-gen - Bug #3857: Use SAMD XOSC / PLL / GCLK to allow lower reference frequencieshttps://osmocom.org/issues/3857?journal_id=146582019-05-29T19:43:37Zmschramm
<ul><li><strong>Status</strong> changed from <i>In Progress</i> to <i>Resolved</i></li><li><strong>% Done</strong> changed from <i>10</i> to <i>100</i></li></ul><p>XA input of Si5351C is now connected to Cortex' PA10, which also can be GCLK_IO4. They are connected via a series resistor and a voltage divider of 47k/30k , as the XA input has V_max = 1,3V. Those two resistors are already in the BOM, and they give 1,286V at 3V3 input. The series resistor ahead of 47k might get little bigger than 0R.</p> osmo-clock-gen - Bug #3857: Use SAMD XOSC / PLL / GCLK to allow lower reference frequencieshttps://osmocom.org/issues/3857?journal_id=148142019-06-13T14:26:25Zlaforge
<ul><li><strong>Status</strong> changed from <i>Resolved</i> to <i>In Progress</i></li><li><strong>% Done</strong> changed from <i>100</i> to <i>70</i></li></ul><p>It looks like only the XA output is connected to the Si5351C, but the XOSC input part on the SAMD has not been implemented.</p> osmo-clock-gen - Bug #3857: Use SAMD XOSC / PLL / GCLK to allow lower reference frequencieshttps://osmocom.org/issues/3857?journal_id=148202019-06-13T15:54:57Zmschramm
<ul></ul><p>PA14 is XIN, and is already routed to the GPIO expansion header (see <a class="issue tracker-2 status-3 priority-2 priority-default closed behind-schedule" title="Feature: Make more GPIOs avaliable for future use (Resolved)" href="https://osmocom.org/issues/3858">#3858</a>). As discussed with laforge, we simply don't have more PCB space for adding a RF-grade connector. maximum frequency on that pad is 32 MHz, so I think this is acceptable.</p>
<p>All external connections on this header and on UEXT will get additional TVS diodes added.</p> osmo-clock-gen - Bug #3857: Use SAMD XOSC / PLL / GCLK to allow lower reference frequencieshttps://osmocom.org/issues/3857?journal_id=148442019-06-18T15:31:28Zmschramm
<ul><li><strong>Status</strong> changed from <i>In Progress</i> to <i>Resolved</i></li><li><strong>% Done</strong> changed from <i>70</i> to <i>100</i></li></ul><p>(all TVS diodes placed)</p>