{"issue":{"state":"open","pull_request":{"diff_url":null,"html_url":null,"patch_url":null},"user":{"avatar_url":"https://secure.gravatar.com/avatar/40ad17caf2fe890d38322389226be841?d=https://a248.e.akamai.net/assets.github.com%2Fimages%2Fgravatars%2Fgravatar-140.png","gravatar_id":"40ad17caf2fe890d38322389226be841","url":"https://api.github.com/users/jbaker0428","login":"jbaker0428","id":1117730},"milestone":null,"assignee":null,"labels":[],"updated_at":"2011-11-03T04:12:26Z","comments":1,"closed_at":null,"url":"https://api.github.com/repos/jbaker0428/Unified-Robotics-Development-Board/issues/8","body":"Need more decoupling capacitors for the microcontrollers. The XMOS specifies one per pin -- for layout reasons with the QFN package we can keep that to one per pair.\r\n\r\nFrom the STM32 manual:\r\n* The VDD pins must be connected to VDD with external decoupling capacitors; one single Tantalum or Ceramic capacitor  minimum 4.7 µF typical 10 µF) for the package + one 100 nF Ceramic capacitor for each VDD pin).\r\n* The VDDA pin must be connected to two external decoupling capacitors (100 nF Ceramic capacitor + 1 µF Tantalum or Ceramic capacitor).\r\n* The VREF+ pin can be connected to the VDDA external power supply. If a separate, external reference voltage is applied on VREF+, a 100 nF and a 1 µF capacitor must be connected on this pin. To compensate peak consumption on Vref, the 1 µF capacitor may be increased up to 10µF when the sampling speed is low. When ADC or DAC is used, VREF+ must remain between 1.8 V and VDDA. VREF+ can be grounded when ADC and DAC are not active; this enables the user to power down an external voltage reference.","html_url":"https://github.com/jbaker0428/Unified-Robotics-Development-Board/issues/8","number":8,"title":"MCU decoupling","id":2128907,"created_at":"2011-11-03T02:52:50Z"},"action":"created","comment":{"user":{"avatar_url":"https://secure.gravatar.com/avatar/40ad17caf2fe890d38322389226be841?d=https://a248.e.akamai.net/assets.github.com%2Fimages%2Fgravatars%2Fgravatar-140.png","gravatar_id":"40ad17caf2fe890d38322389226be841","url":"https://api.github.com/users/jbaker0428","login":"jbaker0428","id":1117730},"updated_at":"2011-11-03T04:12:26Z","url":"https://api.github.com/repos/jbaker0428/Unified-Robotics-Development-Board/issues/comments/2613099","body":"This is 5 ceramics and a 10 uF \"chemical\" cap -- probably electrolytic?","id":2613099,"created_at":"2011-11-03T04:12:26Z"}}