From 882541392f8df09842d15518acca1124d0552c5e Mon Sep 17 00:00:00 2001 From: Stuart Longland Date: Sat, 3 Sep 2016 17:31:15 +1000 Subject: [PATCH] Initial check-in --- .gitignore | 5 + COPYING | 340 +++++++++++++++++++++++++++++++++++ Makefile | 50 ++++++ README.md | 111 ++++++++++++ board.h | 37 ++++ powerctl.c | 506 +++++++++++++++++++++++++++++++++++++++++++++++++++++ uart.c | 116 ++++++++++++ uart.h | 60 +++++++ uartcfg.h | 37 ++++ 9 files changed, 1262 insertions(+) create mode 100644 .gitignore create mode 100644 COPYING create mode 100644 Makefile create mode 100644 README.md create mode 100644 board.h create mode 100644 powerctl.c create mode 100644 uart.c create mode 100644 uart.h create mode 100644 uartcfg.h diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..2641cde --- /dev/null +++ b/.gitignore @@ -0,0 +1,5 @@ +.*.swp +*.swp +*.o +*.elf +*.hex diff --git a/COPYING b/COPYING new file mode 100644 index 0000000..3912109 --- /dev/null +++ b/COPYING @@ -0,0 +1,340 @@ + GNU GENERAL PUBLIC LICENSE + Version 2, June 1991 + + Copyright (C) 1989, 1991 Free Software Foundation, Inc. + 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The licenses for most software are designed to take away your +freedom to share and change it. By contrast, the GNU General Public +License is intended to guarantee your freedom to share and change free +software--to make sure the software is free for all its users. This +General Public License applies to most of the Free Software +Foundation's software and to any other program whose authors commit to +using it. (Some other Free Software Foundation software is covered by +the GNU Library General Public License instead.) You can apply it to +your programs, too. + + When we speak of free software, we are referring to freedom, not +price. Our General Public Licenses are designed to make sure that you +have the freedom to distribute copies of free software (and charge for +this service if you wish), that you receive source code or can get it +if you want it, that you can change the software or use pieces of it +in new free programs; and that you know you can do these things. + + To protect your rights, we need to make restrictions that forbid +anyone to deny you these rights or to ask you to surrender the rights. +These restrictions translate to certain responsibilities for you if you +distribute copies of the software, or if you modify it. + + For example, if you distribute copies of such a program, whether +gratis or for a fee, you must give the recipients all the rights that +you have. You must make sure that they, too, receive or can get the +source code. And you must show them these terms so they know their +rights. + + We protect your rights with two steps: (1) copyright the software, and +(2) offer you this license which gives you legal permission to copy, +distribute and/or modify the software. + + Also, for each author's protection and ours, we want to make certain +that everyone understands that there is no warranty for this free +software. If the software is modified by someone else and passed on, we +want its recipients to know that what they have is not the original, so +that any problems introduced by others will not reflect on the original +authors' reputations. + + Finally, any free program is threatened constantly by software +patents. We wish to avoid the danger that redistributors of a free +program will individually obtain patent licenses, in effect making the +program proprietary. To prevent this, we have made it clear that any +patent must be licensed for everyone's free use or not licensed at all. + + The precise terms and conditions for copying, distribution and +modification follow. + + GNU GENERAL PUBLIC LICENSE + TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION + + 0. This License applies to any program or other work which contains +a notice placed by the copyright holder saying it may be distributed +under the terms of this General Public License. The "Program", below, +refers to any such program or work, and a "work based on the Program" +means either the Program or any derivative work under copyright law: +that is to say, a work containing the Program or a portion of it, +either verbatim or with modifications and/or translated into another +language. (Hereinafter, translation is included without limitation in +the term "modification".) Each licensee is addressed as "you". + +Activities other than copying, distribution and modification are not +covered by this License; they are outside its scope. The act of +running the Program is not restricted, and the output from the Program +is covered only if its contents constitute a work based on the +Program (independent of having been made by running the Program). +Whether that is true depends on what the Program does. + + 1. You may copy and distribute verbatim copies of the Program's +source code as you receive it, in any medium, provided that you +conspicuously and appropriately publish on each copy an appropriate +copyright notice and disclaimer of warranty; keep intact all the +notices that refer to this License and to the absence of any warranty; +and give any other recipients of the Program a copy of this License +along with the Program. + +You may charge a fee for the physical act of transferring a copy, and +you may at your option offer warranty protection in exchange for a fee. + + 2. You may modify your copy or copies of the Program or any portion +of it, thus forming a work based on the Program, and copy and +distribute such modifications or work under the terms of Section 1 +above, provided that you also meet all of these conditions: + + a) You must cause the modified files to carry prominent notices + stating that you changed the files and the date of any change. + + b) You must cause any work that you distribute or publish, that in + whole or in part contains or is derived from the Program or any + part thereof, to be licensed as a whole at no charge to all third + parties under the terms of this License. + + c) If the modified program normally reads commands interactively + when run, you must cause it, when started running for such + interactive use in the most ordinary way, to print or display an + announcement including an appropriate copyright notice and a + notice that there is no warranty (or else, saying that you provide + a warranty) and that users may redistribute the program under + these conditions, and telling the user how to view a copy of this + License. (Exception: if the Program itself is interactive but + does not normally print such an announcement, your work based on + the Program is not required to print an announcement.) + +These requirements apply to the modified work as a whole. If +identifiable sections of that work are not derived from the Program, +and can be reasonably considered independent and separate works in +themselves, then this License, and its terms, do not apply to those +sections when you distribute them as separate works. But when you +distribute the same sections as part of a whole which is a work based +on the Program, the distribution of the whole must be on the terms of +this License, whose permissions for other licensees extend to the +entire whole, and thus to each and every part regardless of who wrote it. + +Thus, it is not the intent of this section to claim rights or contest +your rights to work written entirely by you; rather, the intent is to +exercise the right to control the distribution of derivative or +collective works based on the Program. + +In addition, mere aggregation of another work not based on the Program +with the Program (or with a work based on the Program) on a volume of +a storage or distribution medium does not bring the other work under +the scope of this License. + + 3. You may copy and distribute the Program (or a work based on it, +under Section 2) in object code or executable form under the terms of +Sections 1 and 2 above provided that you also do one of the following: + + a) Accompany it with the complete corresponding machine-readable + source code, which must be distributed under the terms of Sections + 1 and 2 above on a medium customarily used for software interchange; or, + + b) Accompany it with a written offer, valid for at least three + years, to give any third party, for a charge no more than your + cost of physically performing source distribution, a complete + machine-readable copy of the corresponding source code, to be + distributed under the terms of Sections 1 and 2 above on a medium + customarily used for software interchange; or, + + c) Accompany it with the information you received as to the offer + to distribute corresponding source code. (This alternative is + allowed only for noncommercial distribution and only if you + received the program in object code or executable form with such + an offer, in accord with Subsection b above.) + +The source code for a work means the preferred form of the work for +making modifications to it. For an executable work, complete source +code means all the source code for all modules it contains, plus any +associated interface definition files, plus the scripts used to +control compilation and installation of the executable. However, as a +special exception, the source code distributed need not include +anything that is normally distributed (in either source or binary +form) with the major components (compiler, kernel, and so on) of the +operating system on which the executable runs, unless that component +itself accompanies the executable. + +If distribution of executable or object code is made by offering +access to copy from a designated place, then offering equivalent +access to copy the source code from the same place counts as +distribution of the source code, even though third parties are not +compelled to copy the source along with the object code. + + 4. You may not copy, modify, sublicense, or distribute the Program +except as expressly provided under this License. Any attempt +otherwise to copy, modify, sublicense or distribute the Program is +void, and will automatically terminate your rights under this License. +However, parties who have received copies, or rights, from you under +this License will not have their licenses terminated so long as such +parties remain in full compliance. + + 5. You are not required to accept this License, since you have not +signed it. However, nothing else grants you permission to modify or +distribute the Program or its derivative works. These actions are +prohibited by law if you do not accept this License. Therefore, by +modifying or distributing the Program (or any work based on the +Program), you indicate your acceptance of this License to do so, and +all its terms and conditions for copying, distributing or modifying +the Program or works based on it. + + 6. Each time you redistribute the Program (or any work based on the +Program), the recipient automatically receives a license from the +original licensor to copy, distribute or modify the Program subject to +these terms and conditions. You may not impose any further +restrictions on the recipients' exercise of the rights granted herein. +You are not responsible for enforcing compliance by third parties to +this License. + + 7. If, as a consequence of a court judgment or allegation of patent +infringement or for any other reason (not limited to patent issues), +conditions are imposed on you (whether by court order, agreement or +otherwise) that contradict the conditions of this License, they do not +excuse you from the conditions of this License. If you cannot +distribute so as to satisfy simultaneously your obligations under this +License and any other pertinent obligations, then as a consequence you +may not distribute the Program at all. For example, if a patent +license would not permit royalty-free redistribution of the Program by +all those who receive copies directly or indirectly through you, then +the only way you could satisfy both it and this License would be to +refrain entirely from distribution of the Program. + +If any portion of this section is held invalid or unenforceable under +any particular circumstance, the balance of the section is intended to +apply and the section as a whole is intended to apply in other +circumstances. + +It is not the purpose of this section to induce you to infringe any +patents or other property right claims or to contest validity of any +such claims; this section has the sole purpose of protecting the +integrity of the free software distribution system, which is +implemented by public license practices. Many people have made +generous contributions to the wide range of software distributed +through that system in reliance on consistent application of that +system; it is up to the author/donor to decide if he or she is willing +to distribute software through any other system and a licensee cannot +impose that choice. + +This section is intended to make thoroughly clear what is believed to +be a consequence of the rest of this License. + + 8. If the distribution and/or use of the Program is restricted in +certain countries either by patents or by copyrighted interfaces, the +original copyright holder who places the Program under this License +may add an explicit geographical distribution limitation excluding +those countries, so that distribution is permitted only in or among +countries not thus excluded. In such case, this License incorporates +the limitation as if written in the body of this License. + + 9. The Free Software Foundation may publish revised and/or new versions +of the General Public License from time to time. Such new versions will +be similar in spirit to the present version, but may differ in detail to +address new problems or concerns. + +Each version is given a distinguishing version number. If the Program +specifies a version number of this License which applies to it and "any +later version", you have the option of following the terms and conditions +either of that version or of any later version published by the Free +Software Foundation. If the Program does not specify a version number of +this License, you may choose any version ever published by the Free Software +Foundation. + + 10. If you wish to incorporate parts of the Program into other free +programs whose distribution conditions are different, write to the author +to ask for permission. For software which is copyrighted by the Free +Software Foundation, write to the Free Software Foundation; we sometimes +make exceptions for this. Our decision will be guided by the two goals +of preserving the free status of all derivatives of our free software and +of promoting the sharing and reuse of software generally. + + NO WARRANTY + + 11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY +FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN +OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES +PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED +OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF +MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS +TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE +PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, +REPAIR OR CORRECTION. + + 12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING +WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR +REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, +INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING +OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED +TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY +YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER +PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE +POSSIBILITY OF SUCH DAMAGES. + + END OF TERMS AND CONDITIONS + + How to Apply These Terms to Your New Programs + + If you develop a new program, and you want it to be of the greatest +possible use to the public, the best way to achieve this is to make it +free software which everyone can redistribute and change under these terms. + + To do so, attach the following notices to the program. It is safest +to attach them to the start of each source file to most effectively +convey the exclusion of warranty; and each file should have at least +the "copyright" line and a pointer to where the full notice is found. + + + Copyright (C) + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + + +Also add information on how to contact you by electronic and paper mail. + +If the program is interactive, make it output a short notice like this +when it starts in an interactive mode: + + Gnomovision version 69, Copyright (C) year name of author + Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'. + This is free software, and you are welcome to redistribute it + under certain conditions; type `show c' for details. + +The hypothetical commands `show w' and `show c' should show the appropriate +parts of the General Public License. Of course, the commands you use may +be called something other than `show w' and `show c'; they could even be +mouse-clicks or menu items--whatever suits your program. + +You should also get your employer (if you work as a programmer) or your +school, if any, to sign a "copyright disclaimer" for the program, if +necessary. Here is a sample; alter the names: + + Yoyodyne, Inc., hereby disclaims all copyright interest in the program + `Gnomovision' (which makes passes at compilers) written by James Hacker. + + , 1 April 1989 + Ty Coon, President of Vice + +This General Public License does not permit incorporating your program into +proprietary programs. If your program is a subroutine library, you may +consider it more useful to permit linking proprietary applications with the +library. If this is what you want to do, use the GNU Library General +Public License instead of this License. diff --git a/Makefile b/Makefile new file mode 100644 index 0000000..9afaffa --- /dev/null +++ b/Makefile @@ -0,0 +1,50 @@ +# Solar Powered Personal Cloud Power Controller +# (C) 2016 Stuart Longland +# +# This program is free software; you can redistribute it and/or modify it +# under the terms of the GNU General Public License as published by the +# Free Software Foundation; either version 2 of the License, or (at your +# option) any later version. +# +# This program is distributed in the hope that it will be useful, but +# WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +# General Public License for more details. +# +# You should have received a copy of the GNU General Public License along +# with this program; if not, write to the Free Software Foundation, Inc., +# 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + +-include local.mk + +CFLAGS = -Os -g -mmcu=attiny24a -Wall -Werror +LDFLAGS = -mmcu=attiny24a -Wall -Werror +CPPFLAGS = -DF_CPU=1000000UL +CROSS_COMPILE ?= avr- +CC = $(CROSS_COMPILE)gcc +OBJCOPY = $(CROSS_COMPILE)objcopy +OBJDUMP = $(CROSS_COMPILE)objdump +SIZE = $(CROSS_COMPILE)size +PROG_ARGS ?=-c stk500v2 -P /dev/ttyACM0 +PROG_DEV ?= t24 + +.PHONY: clean all + +all: powerctl.ihex + +clean: + -rm *.ihex *.elf *.o + +%.ihex: %.elf + $(OBJCOPY) -j .text -j .data -O ihex $^ $@ + +%.elf: + $(CC) $(LDFLAGS) -o $@ $^ + $(SIZE) -d $@ + +powerctl.elf: powerctl.o uart.o +powerctl.o: board.h +uart.o: uartcfg.h uart.h + +%.pgm: %.ihex + avrdude $(PROG_ARGS) -p $(PROG_DEV) -U flash:w:$^:i diff --git a/README.md b/README.md new file mode 100644 index 0000000..042d984 --- /dev/null +++ b/README.md @@ -0,0 +1,111 @@ +Power controller for solar powered personal cloud +================================================= + +This firmware is intended to control the charging of a battery bank that +powers a small computer cluster running a private cloud system. The +idea is to try to keep the battery within a small range of voltages, +charging from solar or mains based chargers as necessary to top the +battery back up. + +Circuit description +------------------- + +An ATTiny24A microcontroller runs from a 5V rail derived from the +battery. It uses its internal RC oscillator running at 1MHz. + +Connected to PB0 and PB1 are the two MOSFETs that turn on the input +sources, one for solar (PB1), the other for a mains charger (PB0). + +The source pins of these connect to the battery positive input, so when +the FET is on, power may flow from that source to the battery. + +A third MOSFET connects to PB2, this is PWM-controlled to manage some +cooling fans. The internal temperature sensor is used to decide whether +the fans should be on or off, and at what speed. + +Connecting to each input, and to the battery, are separate voltage +dividers, comprising of a 1.5kOhm and 100Ohm resistors. These divide +the input voltage by 16, and the divided voltage is fed into the ADC +pins PA0 (mains), PA1 (solar) and PA2 (battery). + +LEDs connect to PA7, PA6, PA5, PA4 and PA3 to 0v. ICSP is shared with the +LEDs. + +GPIOs +----- + + PB0: Mains MOSFET (active HIGH) + PB1: Solar MOSFET (active HIGH) + PB2: Fan MOSFET (active HIGH) + PB3: nRESET + PA7: Temperature Low LED (active HIGH) + PA6: Temperature High LED (active HIGH) + ICSP MOSI + PA5: Battery Voltage High LED (active HIGH) + ICSP MISO + PA4: Warning LED (active high) + ICSP SCK + Debug Tx + PA3: Battery Voltage Good LED (active HIGH) + PA2: Analogue Input: Battery voltage + PA1: Analogue Input: Solar voltage + PA0: Analogue Input: Mains voltage + +Firmware description +-------------------- + +The firmware may be compiled in DEBUG mode by adding -DDEBUG to the +CPPFLAGS. In this mode, PA4 is used instead for a UART Tx pin at 1200 +baud, 8 bits, no parity, one stop bit. This is done in software, using +Timer 1 as a baud rate generator. + +Timer 1 also does double-duty managing timings for events. + +Timer 0 is used in PWM mode to control the fans. + +The firmware does some quick initialisation before entering the main +loop. If DEBUG is enabled, "INIT xx" will be displayed, where xx is the +value of the MCUSR register. + +Two counters are decremented by the Timer 1 overflow interrupt. +`led_timeout` causes the main loop to update the state of the LEDs when +it hits zero, and `adc_timeout` triggers a new ADC capture run when it +reaches zero. + +The three analogue inputs and temperature sensor are scanned when +`adc_timeout` reaches zero, then the state analysed. The battery +voltage is compared to the previous reading to dissern if the battery is +charging, discharging or holding steady. + +If this state has not changed, a battery state counter increments, +otherwise it is reset. + +The current state of the FETs is checked. Three states are valid: +- Idle state: all FETs off +- Mains charge: MAINS FET turned on +- Solar charge: SOLAR FET turned on + +IF statements at this point compare the battery voltage to the +thresholds, and decide whether to switch voltage or not. + +LED indications +--------------- + +The LEDs have the following meanings: + +Warning LED (PA4; DEBUG undefined): +- Off: No warning condition +- Flashing: Battery below critical threshold or temperature above + maximum threshold +- On: Not used + +When in DEBUG mode, this LED may flicker with serial activity, and will +remain ON when idle. + +Temperature LEDs (PA6, PA7): +- PA7 On, PA6 Off: Temperature below minimum threshold +- PA7 Flashing, PA6 Off: Temperature above minimum threshold +- PA7 Off, PA6 Flashing: Temperature above maximum threshold +- Other states: not used + +Battery LEDs (PA5, PA3): +- PA3 Flashing, PA5 Off: Battery below low threshold +- PA3 Off, PA5 Flashing: Battery above high threshold +- PA3 On, PA5 Off: Battery is in "good" range (between low and high) +- Other states: not used diff --git a/board.h b/board.h new file mode 100644 index 0000000..597815d --- /dev/null +++ b/board.h @@ -0,0 +1,37 @@ +#ifndef _BOARD_H +#define _BOARD_H + +/* LEDs */ +#define LED_TEMP_LOW (1 << 7) +#define LED_TEMP_HIGH (1 << 6) +#define LED_BATT_HIGH (1 << 5) +#define LED_WARNING (1 << 4) +#define LED_BATT_GOOD (1 << 3) +#define LED_PORT PORTA +#define LED_PORT_DDR_REG DDRA +#define LED_PORT_DDR_VAL ( LED_TEMP_LOW \ + | LED_TEMP_HIGH \ + | LED_BATT_HIGH \ + | LED_WARNING \ + | LED_BATT_GOOD ) + +/* MOSFETs */ +#define FET_MAINS (1 << 0) +#define FET_SOLAR (1 << 1) +#define FET_FAN (1 << 2) +#define FET_SRC_MASK (FET_MAINS|FET_SOLAR) +#define FET_PORT PORTB +#define FET_PORT_DDR_REG DDRB +#define FET_PORT_DDR_VAL ( FET_MAINS \ + | FET_SOLAR \ + | FET_FAN ) + +/* ADC channels */ +#define ADC_CH_MAINS (1 << 0) +#define ADC_CH_SOLAR (1 << 1) +#define ADC_CH_BATT (1 << 2) +#define ADC_CH_EN ( ADC_CH_MAINS \ + | ADC_CH_SOLAR \ + | ADC_CH_BATT ) + +#endif diff --git a/powerctl.c b/powerctl.c new file mode 100644 index 0000000..f94d888 --- /dev/null +++ b/powerctl.c @@ -0,0 +1,506 @@ +#include +#include +#include +#include + +#ifdef DEBUG +/*! If enabled, the warning LED doubles as UART Tx pin */ +#include "uart.h" +#endif + +#include "board.h" + +/*! ADMUX setting for selecting 1.1V reference */ +#define ADC_REF_1V1 (2 << REFS0) +/*! ADMUX setting for mains input voltage reading */ +#define ADC_MUX_MAINS (ADC_REF_1V1 | 0x00) +/*! ADMUX setting for solar input voltage reading */ +#define ADC_MUX_SOLAR (ADC_REF_1V1 | 0x01) +/*! ADMUX setting for battery input voltage reading */ +#define ADC_MUX_BATT (ADC_REF_1V1 | 0x02) +/*! ADMUX setting for temperature reading */ +#define ADC_MUX_TEMP (ADC_REF_1V1 | 0x22) + +/*! + * For state machine, the last state of the ADC MUX so we know whether + * to ignore the sample or not. Datasheet recommends discarding samples + * to let things stabalise when switching sources/references. + */ +static volatile uint8_t last_admux = 0; + +/*! + * For state machine, determines what the battery was one sample ago so + * we know if it's charging, discharging, or remaining static. ADC units. + */ +static volatile uint16_t last_adc_batt = 0; + +/*! + * Current reading of the battery voltage in ADC units. + */ +static volatile uint16_t adc_batt = 0; + +/*! + * Current reading of the solar charger voltage in ADC units. + */ +static volatile uint16_t adc_solar = 0; + +/*! + * Current reading of the mains charger voltage in ADC units. + */ +static volatile uint16_t adc_mains = 0; + +/*! + * Current reading of the internal temperature sensor in ADC units. + */ +static volatile uint16_t adc_temp = 0; + +/*! + * How long before we next take a reading? + */ +static volatile uint16_t adc_timeout = 0; +/*! + * How many Timer1 ticks between ADC readings? + */ +#define ADC_TIMEOUT (1200) + +/*! + * State of the battery. + * -1: discharging + * 0: remaining steady + * 1: charging + */ +static volatile int8_t batt_state = 0; +/*! + * The state of the battery at last check. + */ +static volatile int8_t last_batt_state = 0; +/*! + * The number of readings that the battery has maintained this state. + */ +static volatile uint8_t batt_state_counter = 0; +/*! + * How long before we can consider switching sources. + */ +static volatile uint8_t src_timeout = 0; +#define SRC_TIMEOUT (15) /*!< How long to wait before switching */ + +/*! + * How long before we change LED states? + */ +static volatile uint8_t led_timeout = 0; +#define LED_TIMEOUT (150) + +/* + * Temperature ranges and fan PWM settings + */ +#define TEMP_MIN (275 << 6) /*!< ~20°C, approx ADC reading */ +#define TEMP_MAX (295 << 6) /*!< ~30°C, approx ADC reading */ +#define FAN_PWM_MIN (128) /*!< Minimum PWM value */ +#define FAN_PWM_MAX (255) /*!< Maximum PWM value */ + +/* + * ADC Voltage divider settings + */ +#define VDIV_R1 (1500ULL) /*!< R1 = 1.5kOhm */ +#define VDIV_R2 (100ULL) /*!< R2 = 100 Ohm */ +/* + * ADC settings + */ +#define ADC_REF (1100ULL) /*!< AREF = 1.1mV */ +#define ADC_MAX (65535ULL) /*!< ADLAR = 1 */ + +/*! + * Macro for computing ADC measurements. This assumes the input to the + * ADC pin is via a voltage divider made up of resistors R1 and R2, with + * the input voltage applied across both resistors and the ADC measuring + * across R2. + * + * @param mv Voltage in millivolts + * @returns Approximate ADC reading + */ +# define ADC_READ(mv) ( \ + (ADC_MAX * ((uint64_t)(mv)) * VDIV_R2) \ + / \ + (ADC_REF * (VDIV_R1 + VDIV_R2)) \ +) + +/*! + * "Critical" battery voltage. This is considered a serious condition. + */ +#define VBATT_CRIT ADC_READ(11800) +/*! + * "Low" battery voltage. Indication that we should turn a charger on. + */ +#define VBATT_LOW ADC_READ(12000) +/*! + * "High" battery voltage. Indication we should turn the charger off. + */ +#define VBATT_HIGH ADC_READ(13500) + +/* Debug messages */ +#ifdef DEBUG +const char STR_INIT[] PROGMEM = {"INIT "}; +const char STR_ADC[] PROGMEM = {"ADC "}; +const char STR_START[] PROGMEM = {"START "}; +const char STR_READ[] PROGMEM = {"READ "}; +const char STR_NL[] PROGMEM = {"\r\n"}; +#endif + +#define SRC_NONE (0) /*!< Turn off all chargers */ +#define SRC_SOLAR (1) /*!< Turn on solar charger */ +#define SRC_MAINS (2) /*!< Turn on mains charger */ +/*! + * Switch between chargers. This is does a "break-before-make" switchover + * of charging sources to switch from mains to solar, solar to mains, or to + * switch from charging to discharging mode. It expressly forbids turning + * both chargers on simultaneously. + */ +void select_src(uint8_t src) { + switch(src) { + case SRC_SOLAR: + FET_PORT &= ~FET_MAINS; + FET_PORT |= FET_SOLAR; + break; + case SRC_MAINS: + FET_PORT &= ~FET_SOLAR; + FET_PORT |= FET_MAINS; + break; + case SRC_NONE: + default: + FET_PORT &= ~FET_SRC_MASK; + break; + } + src_timeout = SRC_TIMEOUT; +} + +/*! + * Main entrypoint */ +int main(void) { + /* Configure LEDs */ + LED_PORT_DDR_REG = LED_PORT_DDR_VAL; + LED_PORT = 0; + + /* Configure MOSFETs */ + FET_PORT_DDR_REG = FET_PORT_DDR_VAL; + FET_PORT = 0; + + /* Turn on ADC and timers */ + PRR &= ~((1 << PRTIM0) | (1 << PRTIM1) | (1 << PRADC)); + + /* Configure Timer0: Fan PWM */ + TCCR0A = (1 << COM0A1) | (1 << WGM01) | (1 << WGM00); + TCCR0B = (1 << CS00); + /* Half-speed fan until we know what to do */ + OCR0A = 128; + + /* + * Configure Timer1: 1.2kHz System tick timer + * / baud rate generator for debug output + */ + TCCR1A = 0; + TCCR1B = (1 << WGM12) | (1 << CS10); + TCCR1C = 0; + OCR1A = F_CPU/1200; + TIMSK1 = (1 << OCIE1A); + + /* ADC configuration */ + DIDR0 = ADC_CH_EN; + ADMUX = ADC_MUX_TEMP; + ADCSRB = (1 << ADLAR); + ADCSRA = (1 << ADIE) + | (1 << ADPS2) + | (1 << ADPS1) + | (1 << ADPS0); + + /* Configure UART */ + sei(); +#ifdef DEBUG + uart_init(); + uart_tx_str(STR_INIT); + uart_tx_hex_byte(MCUSR); + uart_tx_str(STR_NL); +#endif + MCUSR = 0; + while(1) { + if (!led_timeout) { +#ifndef DEBUG + if ((adc_batt < VBATT_CRIT) + || (adc_temp > TEMP_MAX)) { + /* Warning conditions */ + LED_PORT ^= LED_WARNING; + } else { + LED_PORT &= ~LED_WARNING; + } +#endif + + if (adc_batt < VBATT_LOW) { + /* Battery is low */ + LED_PORT &= ~LED_BATT_HIGH; + LED_PORT ^= LED_BATT_GOOD; + } else if (adc_batt >= VBATT_HIGH) { + /* Battery is above "high" threshold */ + LED_PORT ^= LED_BATT_HIGH; + LED_PORT &= ~LED_BATT_GOOD; + } else { + /* Battery is above "low" threshold */ + LED_PORT |= LED_BATT_GOOD; + LED_PORT &= ~LED_BATT_HIGH; + } + + if (adc_temp < TEMP_MIN) { + LED_PORT |= LED_TEMP_LOW; + LED_PORT &= ~LED_TEMP_HIGH; + } else if (adc_temp < TEMP_MAX) { + LED_PORT ^= LED_TEMP_LOW; + LED_PORT &= ~LED_TEMP_HIGH; + } else { + LED_PORT &= ~LED_TEMP_LOW; + LED_PORT ^= LED_TEMP_HIGH; + } + led_timeout = LED_TIMEOUT; + } + if (!adc_timeout) { + adc_timeout = ADC_TIMEOUT; + ADCSRA |= (1 << ADEN) | (1 << ADSC); +#ifdef DEBUG + uart_tx_str(STR_ADC); + uart_tx_str(STR_READ); +#endif + while(ADCSRA & (1 << ADEN)); +#ifdef DEBUG + uart_tx_str(STR_NL); + uart_tx_str(STR_ADC); + uart_tx('T'); uart_tx_hex_word(adc_temp); + uart_tx(' '); + uart_tx('B'); uart_tx_hex_word(adc_batt); + uart_tx(' '); + uart_tx('L'); uart_tx_hex_word(last_adc_batt); + uart_tx(' '); + uart_tx('d'); + if (last_adc_batt > adc_batt) { + uart_tx('-'); + uart_tx_hex_word(last_adc_batt - adc_batt); + } else { + uart_tx('+'); + uart_tx_hex_word(adc_batt - last_adc_batt); + } + uart_tx(' '); + uart_tx('S'); uart_tx_hex_word(adc_solar); + uart_tx(' '); + uart_tx('M'); uart_tx_hex_word(adc_mains); + uart_tx(' '); + uart_tx('F'); uart_tx_hex_byte(FET_PORT); +#endif + + /* Battery direction */ +#ifdef DEBUG + uart_tx(' '); + uart_tx('b'); +#endif + if ((!last_adc_batt) || (adc_batt == last_adc_batt)) { + batt_state = 0; /* Steady? */ +#ifdef DEBUG + uart_tx('='); +#endif + } else if (adc_batt > last_adc_batt) { + batt_state = 1; +#ifdef DEBUG + uart_tx('+'); +#endif + } else if (adc_batt < last_adc_batt) { + batt_state = -1; +#ifdef DEBUG + uart_tx('-'); +#endif + } + + if (last_batt_state == batt_state) { + batt_state_counter++; + } else { + batt_state_counter = 0; + last_batt_state = batt_state; + } + + /* Battery control */ + uint8_t state = FET_PORT & FET_SRC_MASK; + switch (state) { + case 0: + /* Idle state */ +#ifdef DEBUG + uart_tx('I'); +#endif + if ((adc_batt < VBATT_CRIT) + && (adc_mains > adc_batt)) { + /* Charger urgently needed. */ +#ifdef DEBUG + uart_tx('C'); + uart_tx('M'); +#endif + select_src(SRC_MAINS); + } else if (adc_batt < VBATT_LOW) { + /* Charger needed. */ +#ifdef DEBUG + uart_tx('L'); +#endif + if ((adc_solar >= adc_mains) + && (adc_solar > adc_batt)) { +#ifdef DEBUG + uart_tx('S'); +#endif + select_src(SRC_SOLAR); + } else { +#ifdef DEBUG + uart_tx('M'); +#endif + select_src(SRC_MAINS); + } + } + break; + case FET_SOLAR: +#ifdef DEBUG + uart_tx('S'); +#endif + /* Are we over voltage? */ + if (adc_batt >= VBATT_HIGH) { +#ifdef DEBUG + uart_tx('H'); +#endif + select_src(SRC_NONE); + } else if ((adc_batt < VBATT_CRIT) + && (adc_mains > adc_solar) + && (adc_mains > adc_batt)) { +#ifdef DEBUG + uart_tx('C'); +#endif + select_src(SRC_MAINS); + /* Are we still discharging? */ + } else if ((!src_timeout) + && (adc_mains > adc_batt) + && (batt_state <= 0) + && (batt_state_counter > 10)) { +#ifdef DEBUG + uart_tx('M'); +#endif + select_src(SRC_MAINS); + } else if (src_timeout) { +#ifdef DEBUG + uart_tx('s'); + uart_tx_hex_byte(batt_state_counter); + uart_tx('t'); + uart_tx_hex_byte(src_timeout); +#endif + src_timeout--; + } + break; + case FET_MAINS: +#ifdef DEBUG + uart_tx('M'); +#endif + /* Are we over voltage? */ + if (adc_batt >= VBATT_HIGH) { +#ifdef DEBUG + uart_tx('H'); +#endif + select_src(SRC_NONE); + /* Are we still critical? */ + } else if (adc_batt < VBATT_CRIT) { +#ifdef DEBUG + uart_tx('C'); +#endif + if (adc_mains < adc_solar) { + /* Mains no good, try solar */ +#ifdef DEBUG + uart_tx('S'); +#endif + select_src(SRC_SOLAR); + } + /* Is solar better now? */ + } else if ((!src_timeout) + && (adc_solar > adc_mains)) { +#ifdef DEBUG + uart_tx('S'); +#endif + select_src(SRC_SOLAR); + } else if (src_timeout) { +#ifdef DEBUG + uart_tx('t'); + uart_tx_hex_byte(src_timeout); +#endif + src_timeout--; + } + break; + default: + /* Should not get here */ +#ifdef DEBUG + uart_tx('!'); +#endif + select_src(SRC_NONE); + } + + /* Fan control */ + if (adc_temp > TEMP_MAX) { + /* We're at the maximum temperature, FULL SPEED! */ + OCR0A = FAN_PWM_MAX; + } else if (adc_temp > TEMP_MIN) { + /* Scale fan speed linearly with temperature */ + OCR0A = (((adc_temp - TEMP_MIN) + * (FAN_PWM_MIN - FAN_PWM_MAX)) + / (TEMP_MAX - TEMP_MIN)) + + FAN_PWM_MIN; + } else { + /* Turn fans off completely. */ + OCR0A = 0; + } +#ifdef DEBUG + uart_tx(' '); + uart_tx('f'); + uart_tx_hex_byte(OCR0A); + + uart_tx_str(STR_NL); +#endif + } + } + return 0; +} + +ISR(TIM1_COMPA_vect) { +#ifdef DEBUG + uart_tick(); +#endif + if (adc_timeout) + adc_timeout--; + if (led_timeout) + led_timeout--; +} + +ISR(ADC_vect) { + uint16_t adc = ADCW; + if (last_admux == ADMUX) { + switch(last_admux) { + case ADC_MUX_TEMP: + adc_temp = adc; + ADMUX = ADC_MUX_BATT; + ADCSRA |= (1 << ADSC); + break; + case ADC_MUX_BATT: + last_adc_batt = adc_batt; + adc_batt = adc; + ADMUX = ADC_MUX_SOLAR; + ADCSRA |= (1 << ADSC); + break; + case ADC_MUX_SOLAR: + adc_solar = adc; + ADMUX = ADC_MUX_MAINS; + ADCSRA |= (1 << ADSC); + break; + case ADC_MUX_MAINS: + adc_mains = adc; + default: + ADMUX = ADC_MUX_TEMP; + ADCSRA &= ~(1 << ADEN); + } + } else { + ADCSRA |= (1 << ADSC); + last_admux = ADMUX; + } +} diff --git a/uart.c b/uart.c new file mode 100644 index 0000000..ecb6d4e --- /dev/null +++ b/uart.c @@ -0,0 +1,116 @@ +/*! + * Very simple software UART for AVR microcontrollers + * (C) 2016 Stuart Longland + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include "uart.h" +#include "uartcfg.h" + +#include +#include +#include +#include + +#define TX_BIT (1 << UART_TX_BIT) + +#define BIT_US (1000000/UART_BAUD) /*!< Bit period in microseconds */ + +static volatile uint8_t uart_ticks = 0; + +/*! + * Configure the UART pins. + */ +void uart_init() { + UART_TX_DDR |= TX_BIT; + UART_TX_PORT |= TX_BIT; +} + +static void uart_wait(uint8_t ticks) { + uart_ticks = ticks; + while(uart_ticks); +} + +void uart_tick() { + if (uart_ticks) + uart_ticks--; +} + +/*! + * Send a raw byte to the UART. + */ +void uart_tx(uint8_t byte) { + uint8_t mask = 1; + /* Start bit */ + UART_TX_PORT &= ~TX_BIT; uart_wait(1); + while(mask) { + if (mask & byte) + UART_TX_PORT |= TX_BIT; + else + UART_TX_PORT &= ~TX_BIT; + uart_wait(1); + mask <<= 1; + } + /* Stop bit */ + UART_TX_PORT |= TX_BIT; uart_wait(1); +} + +/*! + * Send a text string (in pgmspace) to the UART. + * String shall be null-terminated! + */ +void uart_tx_str(const char* str) { + char c = pgm_read_byte(str); + while (c) { + str++; + uart_tx(c); + c = pgm_read_byte(str); + } +} + +/*! + * Send a 4-bit nybble to the UART. + */ +void uart_tx_hex(uint8_t nybble) { + if (nybble >= 10) + uart_tx(nybble - 10 + 'a'); + else + uart_tx(nybble + '0'); +} + +/*! + * Send a 8-bit byte to the UART. + */ +void uart_tx_hex_byte(uint8_t byte) { + uart_tx_hex(byte >> 4); + uart_tx_hex(byte & 0x0f); +} + +/*! + * Send a 16-bit word to the UART. + */ +void uart_tx_hex_word(uint16_t word) { + uart_tx_hex_byte(word >> 8); + uart_tx_hex_byte(word & 0xff); +} + +/*! + * Send a 32-bit long word to the UART. + */ +void uart_tx_hex_lword(uint32_t lword) { + uart_tx_hex_word(lword >> 16); + uart_tx_hex_word(lword & 0xffff); +} diff --git a/uart.h b/uart.h new file mode 100644 index 0000000..d4c833a --- /dev/null +++ b/uart.h @@ -0,0 +1,60 @@ +#ifndef _UART_H +#define _UART_H + +/*! + * Very simple software UART for AVR microcontrollers + * (C) 2016 Stuart Longland + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include + +/*! + * Configure the UART pins. + */ +void uart_init(); + +/*! + * UART tick timer + */ +void uart_tick(); + +/*! + * Send a raw byte to the UART. + */ +void uart_tx(uint8_t byte); + +/*! + * Send a text string (in pgmspace) to the UART. + * String shall be null-terminated! + */ +void uart_tx_str(const char* str); + +/*! + * Send a 8-bit byte to the UART. + */ +void uart_tx_hex_byte(uint8_t byte); + +/*! + * Send a 16-bit word to the UART. + */ +void uart_tx_hex_word(uint16_t word); + +/*! + * Send a 32-bit long word to the UART. + */ +void uart_tx_hex_lword(uint32_t lword); +#endif diff --git a/uartcfg.h b/uartcfg.h new file mode 100644 index 0000000..b566cba --- /dev/null +++ b/uartcfg.h @@ -0,0 +1,37 @@ +#ifndef _UARTCFG_H +#define _UARTCFG_H +/*! + * Very simple software UART for AVR microcontrollers + * (C) 2016 Stuart Longland + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +/* The following defines the configuration for the UART driver. */ + +/*! + * UART BAUD rate. This is the speed that we transmit at. For the 1MHz + * RC clock, 4800 is the maximum speed (out of the "standard" ones) that + * will work. If you're running at 8MHz or with an external crystal, you + * may go higher. + */ +#define UART_BAUD (300) + +/* Port settings */ +#define UART_TX_PORT PORTA /*!< GPIO port register for Tx */ +#define UART_TX_DDR DDRA /*!< GPIO direction register for Tx */ +#define UART_TX_BIT 4 /*!< GPIO pin for Tx */ + +#endif