Simple PWM controller
https://bues.ch/cgit/simplepwm.git/
Simplepwm is a small PWM brightness controller for LED lamps.
Microcontroller
Simplepwm supports the following microcontrollers. Not all features are supported on all microcontrollers. See the table for details.
| ATMega-328P | ATMega-88(P) | ATTiny-85 | ATTiny-45 | ATTiny-25 | ATTiny-13 | |
|---|---|---|---|---|---|---|
| Number of analog pot. inputs | 3 | 3 | 1 | 1 | 1 | 1 |
| Number of PWM outputs | 3 | 3 | 1 | 1 | 1 | 1 |
| Power saving | x | x | x | |||
| Battery voltage monitoring | x | x | x | |||
| HSL color model | x | x | ||||
| Remote control via UART | x | x | ||||
| Settings in EEPROM | x | x | ||||
| Debugging via UART | x | x | ||||
| Firmware update via UART | x | x |
Hardware schematics
Schematics for ATMega based setups: schematics-atmega/simplepwm-atmega.pdf
Schematics for ATTiny based setups: schematics-attiny/simplepwm-attiny.pdf
Prebuilt firmware images
The release archives of simplepwm contain prebuilt .hex files for all supported microcontrollers in the hex directory. These hex files can be flashed directly to the microcontroller with a any tool of your choice (e.g. Atmel Studio or avrdude).
The corresponding fuse settings can be found in the file fuses.txt in the same directory.
Building the firmware
The firmware build needs the following tool chain:
- Unix-like operating system
- GNU make
- AVR GCC
- AVR Binutils
- avrdude
Run the following commands to build the firmware:
cd firmware make DEV=t85
Please specify the target microcontroller using the DEV variable as shown above.
Valid values are:
| Microcontroller | make option |
|---|---|
| ATTiny 13 | DEV=t13 |
| ATTiny 25 | DEV=t25 |
| ATTiny 45 | DEV=t45 |
| ATTiny 85 | DEV=t85 |
| ATMega 88 | DEV=m88 |
| ATMega 88P | DEV=m88p |
| ATMega 328P | DEV=m328p |
Additional build options that can be passed to make:
| make option | values | default | description |
|---|---|---|---|
| CONF_PWMLIM | 1-100 | 100 | Limit the maximum PWM duty cycle to this percentage. |
| CONF_PWMINVERT | 0-1 | 0 | Invert the PWM output signal(s). |
| CONF_LOWSPFACT | float | 1.0 | Correction factor for lower range PWM setpoint. |
| CONF_ADCINVERT | 0-1 | 0 | Invert the ADC input signal(s). |
| CONF_ADCHSL | 0-1 | depends on DEV | Interpret the ADC input signals as HSL setpoints instead of RGB. |
| FEAT_HIGHRES | 0-1 | depends on DEV | Higher resolution in very low PWM setpoint range. |
| FEAT_BATTERY | 0-1 | depends on DEV | Battery voltage monitoring |
| FEAT_POWERSAVE | 0-1 | depends on DEV | Power saving / deep sleep |
| FEAT_REMOTE | 0-1 | depends on DEV | Remote control via UART |
| FEAT_EEPROM | 0-1 | depends on DEV | Store settings to EEPROM |
| FEAT_BOOT | 0-1 | depends on DEV | Enable bootloader and firmware updating via UART. |
Flashing the firmware via serial bootloader after build
Run the following commands to flash the firmware via serial bootloader to the target microcontroller.
This only works, if there's already a previous version of SimplePWM running on the chip. If the chip is blank, refer to ISP flashing below.
cd firmware ./flash-usb.sh /dev/ttyUSB0
Flashing the firmware via ISP adapter after build
Run the following commands to flash the firmware via ISP (In System Programmer hardware adapter) to the target microcontroller:
cd firmware make DEV=t85 print_fuses make DEV=t85 write_fuses make DEV=t85 write_mem
Or alternatively use any other of the available AVR flashing tools to program the .hex file and fuses.
License
Copyright (c) 2018-2021 Michael Buesch <m@bues.ch>
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 Street, Fifth Floor, Boston, MA 02110-1301 USA.