From ae0fef4b066aa393abbfc5ad1a434bf3de7d6867 Mon Sep 17 00:00:00 2001 From: Mark van Renswoude Date: Wed, 25 Oct 2017 21:33:49 +0200 Subject: [PATCH] Initial commit --- .gitignore | 2 + Bonfire.sublime-project | 9 ++++ build.ps1 | 1 + platformio.ini | 19 +++++++ src/ledpwmcurve.c | 66 +++++++++++++++++++++++++ src/ledpwmcurve.h | 6 +++ src/main.c | 106 ++++++++++++++++++++++++++++++++++++++++ upload.ps1 | 1 + 8 files changed, 210 insertions(+) create mode 100644 .gitignore create mode 100644 Bonfire.sublime-project create mode 100644 build.ps1 create mode 100644 platformio.ini create mode 100644 src/ledpwmcurve.c create mode 100644 src/ledpwmcurve.h create mode 100644 src/main.c create mode 100644 upload.ps1 diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..85b157b --- /dev/null +++ b/.gitignore @@ -0,0 +1,2 @@ +.pioenvs +*.sublime-workspace \ No newline at end of file diff --git a/Bonfire.sublime-project b/Bonfire.sublime-project new file mode 100644 index 0000000..b01586b --- /dev/null +++ b/Bonfire.sublime-project @@ -0,0 +1,9 @@ +{ + "folders": + [ + { + "path": ".", + "file_exclude_patterns": ["*.sublime-project"] + } + ] +} \ No newline at end of file diff --git a/build.ps1 b/build.ps1 new file mode 100644 index 0000000..c2fb43d --- /dev/null +++ b/build.ps1 @@ -0,0 +1 @@ +& platformio run \ No newline at end of file diff --git a/platformio.ini b/platformio.ini new file mode 100644 index 0000000..89f91b1 --- /dev/null +++ b/platformio.ini @@ -0,0 +1,19 @@ +; PlatformIO Project Configuration File +; +; Build options: build flags, source filter +; Upload options: custom upload port, speed and extra flags +; Library options: dependencies, extra library storages +; Advanced options: extra scripting +; +; Please visit documentation for the other options and examples +; http://docs.platformio.org/page/projectconf.html + +[env:attiny85] +platform = atmelavr +board = attiny85 +upload_protocol = stk500v1 +upload_flags = -P$UPLOAD_PORT -b$UPLOAD_SPEED +board_f_cpu = 1000000L + +upload_port = COM7 +upload_speed = 19200 \ No newline at end of file diff --git a/src/ledpwmcurve.c b/src/ledpwmcurve.c new file mode 100644 index 0000000..b355501 --- /dev/null +++ b/src/ledpwmcurve.c @@ -0,0 +1,66 @@ +#include +#include + +#include "ledpwmcurve.h" + +// Source: https://electronics.stackexchange.com/a/118120 + +// Anti-Log (reverse) lookup table +// y = 0-255 (pwm output), y_range=256 +// x = 0-1023 (10-bit ADC input); +// assuming lower/higher end of ADC out values cannot be used +// discarding first 32 and last 32 values. +// min_x = 32, max_x = 1023-min_x, x_range=1024-2*min_x +// ANTI_LOG[y] = round( x_range*log(y, base=y_range) + min_x ) +// given a value of x, perform a binary lookup on below table +// takes about 28uS for Attiny85 @8MHz clock +const uint16_t ANTI_LOG[] PROGMEM = +{ + 0x0000, 0x0020, 0x0098, 0x00de, 0x0110, 0x0137, 0x0156, 0x0171, 0x0188, 0x019c, 0x01af, 0x01bf, 0x01ce, 0x01dc, 0x01e9, 0x01f5, + 0x0200, 0x020a, 0x0214, 0x021e, 0x0227, 0x022f, 0x0237, 0x023f, 0x0246, 0x024d, 0x0254, 0x025b, 0x0261, 0x0267, 0x026d, 0x0273, + 0x0278, 0x027d, 0x0282, 0x0288, 0x028c, 0x0291, 0x0296, 0x029a, 0x029f, 0x02a3, 0x02a7, 0x02ab, 0x02af, 0x02b3, 0x02b7, 0x02bb, + 0x02be, 0x02c2, 0x02c5, 0x02c9, 0x02cc, 0x02cf, 0x02d3, 0x02d6, 0x02d9, 0x02dc, 0x02df, 0x02e2, 0x02e5, 0x02e8, 0x02eb, 0x02ed, + 0x02f0, 0x02f3, 0x02f5, 0x02f8, 0x02fa, 0x02fd, 0x0300, 0x0302, 0x0304, 0x0307, 0x0309, 0x030b, 0x030e, 0x0310, 0x0312, 0x0314, + 0x0317, 0x0319, 0x031b, 0x031d, 0x031f, 0x0321, 0x0323, 0x0325, 0x0327, 0x0329, 0x032b, 0x032d, 0x032f, 0x0331, 0x0333, 0x0334, + 0x0336, 0x0338, 0x033a, 0x033c, 0x033d, 0x033f, 0x0341, 0x0342, 0x0344, 0x0346, 0x0347, 0x0349, 0x034b, 0x034c, 0x034e, 0x034f, + 0x0351, 0x0352, 0x0354, 0x0355, 0x0357, 0x0358, 0x035a, 0x035b, 0x035d, 0x035e, 0x0360, 0x0361, 0x0363, 0x0364, 0x0365, 0x0367, + 0x0368, 0x0369, 0x036b, 0x036c, 0x036d, 0x036f, 0x0370, 0x0371, 0x0372, 0x0374, 0x0375, 0x0376, 0x0378, 0x0379, 0x037a, 0x037b, + 0x037c, 0x037e, 0x037f, 0x0380, 0x0381, 0x0382, 0x0383, 0x0385, 0x0386, 0x0387, 0x0388, 0x0389, 0x038a, 0x038b, 0x038c, 0x038e, + 0x038f, 0x0390, 0x0391, 0x0392, 0x0393, 0x0394, 0x0395, 0x0396, 0x0397, 0x0398, 0x0399, 0x039a, 0x039b, 0x039c, 0x039d, 0x039e, + 0x039f, 0x03a0, 0x03a1, 0x03a2, 0x03a3, 0x03a4, 0x03a5, 0x03a6, 0x03a7, 0x03a8, 0x03a9, 0x03aa, 0x03ab, 0x03ab, 0x03ac, 0x03ad, + 0x03ae, 0x03af, 0x03b0, 0x03b1, 0x03b2, 0x03b3, 0x03b4, 0x03b4, 0x03b5, 0x03b6, 0x03b7, 0x03b8, 0x03b9, 0x03ba, 0x03ba, 0x03bb, + 0x03bc, 0x03bd, 0x03be, 0x03bf, 0x03bf, 0x03c0, 0x03c1, 0x03c2, 0x03c3, 0x03c3, 0x03c4, 0x03c5, 0x03c6, 0x03c7, 0x03c7, 0x03c8, + 0x03c9, 0x03ca, 0x03ca, 0x03cb, 0x03cc, 0x03cd, 0x03cd, 0x03ce, 0x03cf, 0x03d0, 0x03d0, 0x03d1, 0x03d2, 0x03d3, 0x03d3, 0x03d4, + 0x03d5, 0x03d6, 0x03d6, 0x03d7, 0x03d8, 0x03d8, 0x03d9, 0x03da, 0x03db, 0x03db, 0x03dc, 0x03dd, 0x03dd, 0x03de, 0x03df, 0x03df +}; + +// Binary lookup using above table +uint8_t antilog(uint16_t value) +{ + uint8_t result = 0x80; + uint16_t lookupValue; + + for(uint16_t jumpOffset = 0x40; jumpOffset > 0; jumpOffset >>= 1) + { + lookupValue = pgm_read_word_near(ANTI_LOG + result); + if (lookupValue > value) + { + result -= jumpOffset; + } + else if (lookupValue < value) + { + result |= jumpOffset; + } + else + { + return result; + } + } + + if (pgm_read_word_near(ANTI_LOG + result) > value) + { + result -= 1; + } + + return result; +} diff --git a/src/ledpwmcurve.h b/src/ledpwmcurve.h new file mode 100644 index 0000000..c75a33e --- /dev/null +++ b/src/ledpwmcurve.h @@ -0,0 +1,6 @@ +#ifndef __LEDPWMCurve +#define __LEDPWMCurve + +extern uint8_t antilog(uint16_t value); + +#endif \ No newline at end of file diff --git a/src/main.c b/src/main.c new file mode 100644 index 0000000..2ed2053 --- /dev/null +++ b/src/main.c @@ -0,0 +1,106 @@ +#include +#include +#include +#include +#include "ledpwmcurve.h" + + +#define PWMMin 128 +#define PWMMax 1024 +#define PWMRange (PWMMax - PWMMin) + +#define PWMRandomValue() ((random() % PWMRange) + PWMMin) + +#define DelayMin 5 +#define DelayMax 50 +#define DelayChange 1 +#define DelayChangeSteps ((DelayMax - DelayMin) / DelayChange) + + +void var_delay_ms(int n); + + + +int main() +{ + uint16_t currentValue = PWMRandomValue(); + uint16_t targetValue = currentValue; + uint16_t startValue = currentValue; + + uint16_t speedUpUntil = currentValue; + uint16_t slowDownFrom = currentValue; + + uint8_t delay = DelayMax; + + #define goingUp (targetValue > currentValue) + + + // -- Set up PWM + // Set all ports as output (leave none as floating input) + DDRB = 0b11111111; + + // Set Timer 0 to internal clock, no prescaling. + // See chapter 11.9 of the ATTiny85 datasheet + TCCR0B |= (1 << CS00); + + // Set to 'Fast PWM' mode + TCCR0A |= (1 << WGM01) | (1 << WGM00); + + // Clear OC0B output on compare match, upwards counting + TCCR0A |= (1 << COM0B1); + + + while (1) + { + if (targetValue == currentValue) + { + do + { + targetValue = PWMRandomValue(); + } while (targetValue == currentValue); + + startValue = currentValue; + speedUpUntil = goingUp ? startValue + DelayChangeSteps : startValue - DelayChangeSteps; + slowDownFrom = goingUp ? targetValue - DelayChangeSteps : targetValue + DelayChangeSteps; + } + + + if (goingUp) + { + currentValue++; + + if (currentValue < speedUpUntil) + delay -= DelayChange; + else if (currentValue > slowDownFrom) + delay += DelayChange; + else + delay = DelayMin; + } + else + { + currentValue--; + + if (currentValue > speedUpUntil) + delay -= DelayChange; + else if (currentValue < slowDownFrom) + delay += DelayChange; + else + delay = DelayMin; + } + + + // Update PWM value + OCR0B = antilog(currentValue); + var_delay_ms(delay); + } + + return 0; +} + + +// Source: http://www.avrfreaks.net/forum/how-use-delay-variable +void var_delay_ms(int n) +{ + while(n--) + _delay_ms(1); +} \ No newline at end of file diff --git a/upload.ps1 b/upload.ps1 new file mode 100644 index 0000000..9b3c625 --- /dev/null +++ b/upload.ps1 @@ -0,0 +1 @@ +& platformio run --target upload \ No newline at end of file