https://wiki.batc.org.uk/index.php?action=history&feed=atom&title=DATV_Repeater_i2c_Interface 2026-05-12T20:59:26Z Revision history for this page on the wiki MediaWiki 1.35.6 https://wiki.batc.org.uk/index.php?title=DATV_Repeater_i2c_Interface&diff=9408&oldid=prev 2022-02-21T12:15:03Z

<p></p> <table class="diff diff-contentalign-left diff-editfont-monospace" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en-GB"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 12:15, 21 February 2022</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l3" >Line 3:</td> <td colspan="2" class="diff-lineno">Line 3:</td></tr> <tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>  dtparam=i2c_arm=on</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>  dtparam=i2c_arm=on</div></td></tr> <tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>  dtoverlay=i2c-gpio,i2c_gpio_sda=14,i2c_gpio_scl=15</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>  dtoverlay=i2c-gpio,i2c_gpio_sda=14,i2c_gpio_scl=15</div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">==Raspberry Pi interface==</ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>The i2c interface on the Raspberry Pi uses 3.3v and requires 1.8k resistors to the 3.3v supply (GPIO pin 1) on both the sda and scl lines.</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>The i2c interface on the Raspberry Pi uses 3.3v and requires 1.8k resistors to the 3.3v supply (GPIO pin 1) on both the sda and scl lines.</div></td></tr> </table>

G8GTZ https://wiki.batc.org.uk/index.php?title=DATV_Repeater_i2c_Interface&diff=9363&oldid=prev 2022-02-18T12:11:14Z

<p></p> <table class="diff diff-contentalign-left diff-editfont-monospace" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en-GB"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 12:11, 18 February 2022</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l1" >Line 1:</td> <td colspan="2" class="diff-lineno">Line 1:</td></tr> <tr><td class='diff-marker'>−</td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>The i2c interface for the repeater controller is configured to use GPIO pin 8 for sda and GPIO pin 10 for scl.  Note that these are not the default Raspberry Pi i2c pins (normally pins 3 and 5 which are reserved for the clock module) and must be addressed using the interface /dev/i2c-22).  The <del class="diffchange diffchange-inline">configtxt </del>file is modified to activate these pins for 100 kHz i2c with the lines</div></td><td class='diff-marker'>+</td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline"> Back to [[Repeater Controller|repeater controller]] main page</ins></div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>The i2c interface for the repeater controller is configured to use GPIO pin 8 for sda and GPIO pin 10 for scl.  Note that these are not the default Raspberry Pi i2c pins (normally pins 3 and 5<ins class="diffchange diffchange-inline">, </ins>which are reserved for the <ins class="diffchange diffchange-inline">future </ins>clock module <ins class="diffchange diffchange-inline">in the repeater</ins>) and must be addressed using the interface /dev/i2c-22).  The <ins class="diffchange diffchange-inline">config.txt </ins>file is modified to activate these pins for 100 kHz i2c with the lines</div></td></tr> <tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>  dtparam=i2c_arm=on</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>  dtparam=i2c_arm=on</div></td></tr> <tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>  dtoverlay=i2c-gpio,i2c_gpio_sda=14,i2c_gpio_scl=15</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>  dtoverlay=i2c-gpio,i2c_gpio_sda=14,i2c_gpio_scl=15</div></td></tr> <tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l5" >Line 5:</td> <td colspan="2" class="diff-lineno">Line 6:</td></tr> <tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>The i2c interface on the Raspberry Pi uses 3.3v and requires 1.8k resistors to the 3.3v supply (GPIO pin 1) on both the sda and scl lines.</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>The i2c interface on the Raspberry Pi uses 3.3v and requires 1.8k resistors to the 3.3v supply (GPIO pin 1) on both the sda and scl lines.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr> <tr><td class='diff-marker'>−</td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>The audio switch board i2c interface should ideally be <del class="diffchange diffchange-inline">drivenm </del>with 5v i2c, but does work with 3.3v i2c with reduced noise immunity.  The noise immunity can be improved by using an i2c level shifter</div></td><td class='diff-marker'>+</td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>The audio switch board i2c interface should ideally be <ins class="diffchange diffchange-inline">driven </ins>with 5v i2c, but does work with 3.3v i2c with reduced noise immunity.  The noise immunity can be improved by using an i2c level shifter <ins class="diffchange diffchange-inline">such as the PCA9306 available on PCBs such as this: https://www.sparkfun.com/products/15439.  Other users have reported that the Raspberry Pi interfaces reliably with the MCP23008 audio switch powered from 5v; a full discussion can be found here: https://forums.raspberrypi.com/viewtopic.php?t=329873.</ins></div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> </div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">The i2c address for the MCP23008 audio switch is in the range 0x20 to 0x27.  The final digit can be selected by jumpers on the PCB.  The address used by the controller is set in the range 0-7 by this paramter in the config file:</ins></div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline"> audioi2caddress=7</ins></div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">The base address of 0x20 is hard-coded.</ins></div></td></tr> </table>

G8GKQ https://wiki.batc.org.uk/index.php?title=DATV_Repeater_i2c_Interface&diff=9362&oldid=prev 2022-02-18T11:55:47Z

<p>Created page with &quot;The i2c interface for the repeater controller is configured to use GPIO pin 8 for sda and GPIO pin 10 for scl. Note that these are not the default Raspberry Pi i2c pins (norm...&quot;</p> <p><b>New page</b></p><div>The i2c interface for the repeater controller is configured to use GPIO pin 8 for sda and GPIO pin 10 for scl. Note that these are not the default Raspberry Pi i2c pins (normally pins 3 and 5 which are reserved for the clock module) and must be addressed using the interface /dev/i2c-22). The configtxt file is modified to activate these pins for 100 kHz i2c with the lines<br /> dtparam=i2c_arm=on<br /> dtoverlay=i2c-gpio,i2c_gpio_sda=14,i2c_gpio_scl=15<br /> <br /> The i2c interface on the Raspberry Pi uses 3.3v and requires 1.8k resistors to the 3.3v supply (GPIO pin 1) on both the sda and scl lines.<br /> <br /> The audio switch board i2c interface should ideally be drivenm with 5v i2c, but does work with 3.3v i2c with reduced noise immunity. The noise immunity can be improved by using an i2c level shifter</div>

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