Changes between Version 1 and Version 2 of WikiStart


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Timestamp:
Mar 8, 2017, 6:27:21 PM (7 years ago)
Author:
bouyer
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  • WikiStart

    v1 v2  
    1 = Welcome to Trac 1.0.10 =
     1= A low-cost SoC power measurement platform =
    22
    3 Trac is a '''minimalistic''' approach to '''web-based''' management of
    4 '''software projects'''. Its goal is to simplify effective tracking and handling of software issues, enhancements and overall progress.
     3Evaluating software impact on power consumtion is not easy. Using a simple multimeter on the power line is not accurate enough because there are big variation in input current. A higher sampling frequency is needed. Also you have to correlate the power data with the various phases of a software (separate initialisation from the computation part for example).
    54
    6 All aspects of Trac have been designed with the single goal to
    7 '''help developers write great software''' while '''staying out of the way'''
    8 and imposing as little as possible on a team's established process and
    9 culture.
     5Our idea is to build a low-cost power measurement tool around a cheap microcontroller, in this case from the pic18 family. We use its ADC to get current and voltage sample of the power line at a high enough rate. We also use its GPIOs as input, connected to GPIOs of the SoC being evaluated, to track and report various software state on the SoC.
    106
    11 As all Wiki pages, this page is editable, this means that you can
    12 modify the contents of this page simply by using your
    13 web-browser. Simply click on the "Edit this page" link at the bottom
    14 of the page. WikiFormatting will give you a detailed description of
    15 available Wiki formatting commands.
     7We choose to use a pic18fj53. Its has a 12 bits ADC which can do up to 80ksp/s, runs at 48Mhz and has a USB interface. Unfortunably during developement we found that the USB interface, when enabled, would dramatically decrease the ADC's accuracy. So we choose to use the serial port on the PIC side and added an external USB/serial bridge.
    168
    17 "[wiki:TracAdmin trac-admin] ''yourenvdir'' initenv" created
    18 a new Trac environment, containing a default set of wiki pages and some sample
    19 data. This newly created environment also contains
    20 [wiki:TracGuide documentation] to help you get started with your project.
     9The requirement are:
     10- inputs between 0 and 2A, 0 and 20V
     11- 4 GPIOs to connect with the SoC being evaluated
    2112
    22 You can use [wiki:TracAdmin trac-admin] to configure
    23 [http://trac.edgewall.org/ Trac] to better fit your project, especially in
    24 regard to ''components'', ''versions'' and ''milestones''.
     13A 1.350V precision diode is used as a voltage reference for the ADC. The input voltage is feed to ADC input 0 (AN0) via a voltage diviser. To cover the input range with enough accuracy 3 different values can be selected with a jumper.
     14
     153 Shut resistors are used for current measurements, selectable with a jumper. An amplifier will multiply the shut's voltage before feeding it to AN1.
     16
     17RB0-RB3 are used to get 4 GPIO status from the SoC.
    2518
    2619
    27 TracGuide is a good place to start.
    2820
    29 Enjoy! [[BR]]
    30 ''The Trac Team''
    3121
    32 == Starting Points ==
    33 
    34  * TracGuide --  Built-in Documentation
    35  * [http://trac.edgewall.org/ The Trac project] -- Trac Open Source Project
    36  * [http://trac.edgewall.org/wiki/TracFaq Trac FAQ] -- Frequently Asked Questions
    37  * TracSupport --  Trac Support
    38 
    39 For a complete list of local wiki pages, see TitleIndex.