{"id":791,"date":"2019-03-14T12:49:25","date_gmt":"2019-03-14T12:49:25","guid":{"rendered":"http:\/\/lora.vsb.cz\/?page_id=791"},"modified":"2019-11-21T07:16:03","modified_gmt":"2019-11-21T07:16:03","slug":"low-power-mode","status":"publish","type":"page","link":"https:\/\/lora.vsb.cz\/index.php\/low-power-mode\/","title":{"rendered":"Low Power Mode"},"content":{"rendered":"<p>To save power, the ATmega MCU supports some sleep modes, and unused peripherals can be turned off. The sleep modes differ in what parts remain active, by the sleep duration and the time needed to wake-up. We control sleep mode and active peripherals with the excellent <strong>Low-Power library<\/strong> by <a href=\"https:\/\/github.com\/rocketscream\/Low-Power\" target=\"_blank\" rel=\"noopener noreferrer\">Rocketscream<\/a>. The Low-Power library is simple to use but very powerful. The statement<\/p>\n<pre>LowPower.powerDown(SLEEP_8S, ADC_OFF, BOD_OFF);<\/pre>\n<p>puts the <code>MCU<\/code> in <code>SLEEP_MODE_PWR_DOWN<\/code> for 8 s. It disables the <code>ADC<\/code> and the <code>BOD<\/code>. Power-down sleep means that all chip functions are disabled until the next interrupt.<\/p>\n<p>The <code>for<\/code> loop ensure multiple run of sleep time as:<\/p>\n<pre><span style=\"color: #339966;\">for<\/span> (<span style=\"color: #008000;\">int<\/span> i=0;i&lt;10;i++) <span style=\"color: #999999;\">\/\/ 10 times 8 seconds sleep<\/span>\r\n{\r\n<span style=\"color: #ff6600;\">LowPower.powerDown<\/span>(<span style=\"color: #008000;\">SLEEP_8S, ADC_OFF, BOD_OFF<\/span>); <span style=\"color: #999999;\">\/\/sleep 8 seconds<\/span>\r\n}\r\n<\/pre>\n<p>We provide professional power analysis via <a href=\"https:\/\/www.keysight.com\/en\/pd-2747858-pn-N6705C\/\">N6705C DC Power Analyzer by Keysight<\/a> with voltmeter accuracy: Up to 0.025% + 50 \u00b5V, up to 18 bits, Ammeter accuracy: Up to 0.025% + 8 nA, up to 18 bits.<\/p>\n<p>The power consumption in LowPower mode is less than 100 uA.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-861\" src=\"http:\/\/lora.vsb.cz\/wp-content\/uploads\/2019\/05\/adafruit_dht22_power2.png\" alt=\"\" width=\"1875\" height=\"527\" srcset=\"https:\/\/lora.vsb.cz\/wp-content\/uploads\/2019\/05\/adafruit_dht22_power2.png 1875w, https:\/\/lora.vsb.cz\/wp-content\/uploads\/2019\/05\/adafruit_dht22_power2-300x84.png 300w, https:\/\/lora.vsb.cz\/wp-content\/uploads\/2019\/05\/adafruit_dht22_power2-768x216.png 768w, https:\/\/lora.vsb.cz\/wp-content\/uploads\/2019\/05\/adafruit_dht22_power2-1024x288.png 1024w\" sizes=\"auto, (max-width: 1875px) 100vw, 1875px\" \/><\/p>\n<p style=\"text-align: center;\">Sample of power consumption measurement for Adafruit32u4 with RFM95 and LowPower mode enabled.<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>To save power, the ATmega MCU supports some sleep modes, and unused peripherals can be turned off. The sleep modes differ in what parts remain active, by the sleep duration and the time needed to wake-up. We control sleep mode and active peripherals with the excellent Low-Power library by Rocketscream. The Low-Power library is simple [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-791","page","type-page","status-publish","hentry","post"],"_links":{"self":[{"href":"https:\/\/lora.vsb.cz\/index.php\/wp-json\/wp\/v2\/pages\/791","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lora.vsb.cz\/index.php\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/lora.vsb.cz\/index.php\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/lora.vsb.cz\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/lora.vsb.cz\/index.php\/wp-json\/wp\/v2\/comments?post=791"}],"version-history":[{"count":15,"href":"https:\/\/lora.vsb.cz\/index.php\/wp-json\/wp\/v2\/pages\/791\/revisions"}],"predecessor-version":[{"id":906,"href":"https:\/\/lora.vsb.cz\/index.php\/wp-json\/wp\/v2\/pages\/791\/revisions\/906"}],"wp:attachment":[{"href":"https:\/\/lora.vsb.cz\/index.php\/wp-json\/wp\/v2\/media?parent=791"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}