https://osmocom.org/https://osmocom.org/favicon.ico?16647414092020-04-18T20:29:15ZOpen Source Mobile CommunicationsOsmoGSMTester - Feature #4502: osmo-gsm-tester: support gpio controlled step attenuators of the LTHW main unithttps://osmocom.org/issues/4502?journal_id=180252020-04-18T20:29:15Zpespin
<ul><li><strong>Status</strong> changed from <i>New</i> to <i>Feedback</i></li><li><strong>Assignee</strong> changed from <i>pespin</i> to <i>dexter</i></li></ul><p>Assigning to <a class="user active" href="https://osmocom.org/users/15">dexter</a> to provide here with the information he has available for the device.</p> OsmoGSMTester - Feature #4502: osmo-gsm-tester: support gpio controlled step attenuators of the LTHW main unithttps://osmocom.org/issues/4502?journal_id=180392020-04-20T09:50:45Zdexter
<ul><li><strong>File</strong> <a href="/attachments/4086">pinouts.jpg</a> <a class="icon-only icon-download" title="Download" href="/attachments/download/4086/pinouts.jpg">pinouts.jpg</a> added</li><li><strong>Status</strong> changed from <i>Feedback</i> to <i>New</i></li><li><strong>Assignee</strong> changed from <i>dexter</i> to <i>pespin</i></li></ul><p>The step attenuator is controlled via the GPIO interface of the APU directly. As far as I know there are 4 attenuators. The synchronous serial interface is wired in parallel while the latch enable lines are wired individually. The attenuation value is shifted into the internal shift-register of all attenuator at once. The latch enable line latches the value to the outputs of the shift register to the register that controls the attenuation.</p>
<p>There is a git repository with a driver and a utility<br />git.sysmocom.de/sysmo-att-ctrl</p>
<p>The attenuator is an ZX76-31R5-SP+ from Mini-Circuits.</p>
<p>As far as I remember the GPIO chip in the APU is an NCT5104, some Info about the driver can be found here: <a class="external" href="https://github.com/tasanakorn/linux-gpio-nct5104d/pull/3/files">https://github.com/tasanakorn/linux-gpio-nct5104d/pull/3/files</a></p> OsmoGSMTester - Feature #4502: osmo-gsm-tester: support gpio controlled step attenuators of the LTHW main unithttps://osmocom.org/issues/4502?journal_id=266012023-03-31T15:28:02Zpespin
<ul><li><strong>Priority</strong> changed from <i>Normal</i> to <i>Low</i></li></ul>