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171 lines
6.2 KiB
171 lines
6.2 KiB
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\documentclass[11pt]{article}
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%Gummi|065|=)
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\usepackage{graphicx}
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\usepackage{caption}
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\usepackage{xcolor}
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\usepackage[vcentering,dvips]{geometry}
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\geometry{papersize={6in,9in},total={4.5in,6.8in}}
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%\title{\textbf{Door Alarm}}
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\author{Steak Electronics}
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\date{}
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\begin{document}
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%\maketitle
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%\tableofcontents
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\textcolor{green!60!blue!70}{
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\section{Attiny Solar Energy Harvest Tests}}
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I have the following:
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\begin{itemize}
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\item Solar panels
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\item Attiny 10
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\end{itemize}
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To this list, I will add a supercap, and an energy harvesting IC. The goal being to load the super cap during the day, and to run 24/7. I will need an exceptionally low power micro. The super cap will need to be about 3.3V or 5V.
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\textcolor{green!60!blue!70}{
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\subsection{Micro Considerations}}
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The Arduino Atmega328P is not an option. I'm looking to have a current draw of only 1mA max, (ideally 500uA) when active. Moteino is also not an option for this. Those are made for batteries. I want to be battery free. A super cap, however can be used to store energy. I'll get to that shortly.
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For micros, I have some Attiny10 on hand, and these have a reasonably low power pull in active mode. Let's build those up first. What will the micro do? No idea. I haven't a clue.
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\textcolor{green!60!blue!70}{
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\subsubsection{Micro Notes}}
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Must run at 1.8V / 1MHz per front page of data sheet, for 200uA draw in active mode.
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\\
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\\
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\textcolor{green!60!blue!70}{
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\subsection{Energy Storage}}
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I don't want a battery. Let's go with a super cap. The solar panels will only be active some of the time, so I will want to harvest energy with some kind of IC into the cap when the sun is out.\footnote{Reference: www.analog.com/media/en/technical-documentation/technical-articles/solarenergyharvesting.pdf is a start. I'll need to do more research.}
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\textcolor{green!60!blue!70}{ \subsection{Make parts, not scrap}} I will
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want to make sure that all parts I build are perf board parts, not
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breadboard scrap (to be torn down and rebuilt again). This is an Attiny,
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so no need to test much, yet.
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\textcolor{green!60!blue!70}{ \subsubsection{Testing Arduino Loader}}
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Tested this with the blink_LED.c in code folder. The code is as simple as possible.
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It is the following:
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\begin{verbatim}
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//#include <xc.h>
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#include <avr/io.h>
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#include <util/delay.h>
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int main(void)
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{
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// PB2 output
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DDRB = 1<<2;
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while(1)
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{
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// Toggle PB2
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PINB = 1<<2;
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_delay_ms(500);
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}
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}
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\end{verbatim}
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When programmed in Mplab, with XC8 compiler, and Attiny10 support, I get the following
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hex output:
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\begin{verbatim}
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:100000000AC020C01FC01EC01DC01CC01BC01AC01B
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:1000100019C018C017C011271FBFCFE5D0E0DEBF41
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:0A002000CDBF03D000C0F894FFCF5D
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:10002A0044E041B940B95FE966E871E05150604087
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:0A003A007040E1F700C00000F5CFB0
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:02004400DDCF0E
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:00000001FF
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\end{verbatim}
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The content of this hex isn't the focus of this passage. Instead, I want you to review the
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results of a D for Dump Memory, by the Arduino Loader.
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\begin{verbatim}
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Current memory state:
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registers, SRAM
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+0 +1 +2 +3 +4 +5 +6 +7 +8 +9 +A +B +C +D +E +F
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0000: 05 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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0010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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0020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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0030: 00 00 00 00 00 00 03 00 00 79 00 03 00 00 00 00
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0040: B7 AD AE FA 58 70 63 6B FB 5A B4 1B FF FF 35 3F
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0050: 67 D7 33 43 DF 5F FB 72 C9 7D FE E9 9D C5 00 12
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NVM lock
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+0 +1 +2 +3 +4 +5 +6 +7 +8 +9 +A +B +C +D +E +F
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3F00: FF FF
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configuration
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+0 +1 +2 +3 +4 +5 +6 +7 +8 +9 +A +B +C +D +E +F
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3F40: FF FF
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calibration
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+0 +1 +2 +3 +4 +5 +6 +7 +8 +9 +A +B +C +D +E +F
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3F80: 79 FF
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device ID
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+0 +1 +2 +3 +4 +5 +6 +7 +8 +9 +A +B +C +D +E +F
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3FC0: 1E 90 03 FF
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program
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+0 +1 +2 +3 +4 +5 +6 +7 +8 +9 +A +B +C +D +E +F
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4000: 0A C0 20 C0 1F C0 1E C0 1D C0 1C C0 1B C0 1A C0
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4010: 19 C0 18 C0 17 C0 11 27 1F BF CF E5 D0 E0 DE BF
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4020: CD BF 03 D0 00 C0 F8 94 FF CF 44 E0 41 B9 40 B9
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4030: 5F E9 66 E8 71 E0 51 50 60 40 70 40 E1 F7 00 C0
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4040: 00 00 F5 CF DD CF FF FF FF FF FF FF FF FF FF FF
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4050: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
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4060: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
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(...some memory omitted here for brevity...)
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43E0: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
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43F0: FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
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\end{verbatim}
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Notice that the "AC020C01F" is set. That is from the hex. But the 01000...
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before it seems to be missing. Some deciphering of how the Arduino programs
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the Attiny is in order here. It also doesn't end the same.
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Regardless, when programming, the Arduino reports 70 bytes written, and
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likewise in the Mplab project memorymap.xml file, it also notes 70 bytes
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for the sketch. This lines up.\footnote{Although for an unknown reason, every command registers twice on the Arduino serial monitor, but this appears to be harmless.}
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The blinking LED works. Let's move on.
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\textcolor{green!60!blue!70}{ \subsubsection{IO Port Switching Speed}}
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Using the above code without any delay_ms, I get the following results from a default clock
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speed, and a 128KHz clock speed. This test was done to confirm that I could change the clock with
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\begin{verbatim}
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//Write CCP
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CCP = 0xD8;
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//change CLK to 128KHz
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CLKMSR = 0b01;
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\end{verbatim}
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There was no issue.
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\begin{verbatim}
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Default CLK (8MHz? or 1MHz?): 160KHz IO Switch
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128KHz CLK: 2.5KHz IO Switch
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\end{verbatim}
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I am going to pursue 128KHz for starters, for lower current dissipation. Note that with the Arduino loader, it is cumbersome to test and change code as you move along. It is
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therefore going to be necessary to use a programmer, with a dedicated header on board.
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\textcolor{green!60!blue!70}{ \subsubsection{VCC 1.8V}}
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The lowest power supported: 1.8V can be applied, without any configuration
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needed. It does not affect IO switching speed (although obviously amplitude is affected).
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\begin{verbatim}
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128KHz CLK (5.0V): 2.5256 KHz IO switch
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128KHz CLK (3.3V): 2.5477 KHz IO switch
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128KHz CLK (1.8V): 2.5849 KHz IO switch
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\end{verbatim}
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As voltage drops, IO increases.
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\\
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\textbf{VCC Dropout voltage:}
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From 1.5, it drops out at 1.248V or so. Comes back at about 1.34V
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\\
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Test size of 1.
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\\
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Can't run this with one (AA) battery, but you could with 2.
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\\
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Current Draw: 128KHz - IO test, 1.8V, 0.08mA (~78uA) (tested w/3478A)
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\\
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\end{document}
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