From aa6c480f40241471d12c317c72acd94c2148a991 Mon Sep 17 00:00:00 2001 From: Robin Haberkorn Date: Thu, 11 Feb 2021 08:10:12 +0100 Subject: added the K7637 firmware --- pwm.c | 347 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 347 insertions(+) create mode 100644 pwm.c (limited to 'pwm.c') diff --git a/pwm.c b/pwm.c new file mode 100644 index 0000000..97c3dac --- /dev/null +++ b/pwm.c @@ -0,0 +1,347 @@ +/* +Copyright 2021 Robin Haberkorn + +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, see . +*/ + +#include +#include + +#include +#include +#include + +#include "debug.h" +#include "pwm.h" + +/** + * Translation table from brightness to PWM setting to allow smooth + * fadings (8-bit timers). + * + * This is calculated by the formula: + * ``` + * uint16_t resolution = 0xFF; + * pwm_table8[x] = x ? round(pow((double)x / 255.0, 2.5) * resolution) : 0; + * ``` + */ +static const uint8_t pwm_table8[256] PROGMEM = { + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x01, + 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x02, 0x02, 0x02, + 0x02, 0x02, 0x02, 0x02, 0x02, 0x03, 0x03, 0x03, 0x03, 0x03, 0x04, 0x04, + 0x04, 0x04, 0x04, 0x05, 0x05, 0x05, 0x05, 0x06, 0x06, 0x06, 0x06, 0x07, + 0x07, 0x07, 0x07, 0x08, 0x08, 0x08, 0x09, 0x09, 0x09, 0x0A, 0x0A, 0x0A, + 0x0B, 0x0B, 0x0C, 0x0C, 0x0C, 0x0D, 0x0D, 0x0E, 0x0E, 0x0F, 0x0F, 0x0F, + 0x10, 0x10, 0x11, 0x11, 0x12, 0x12, 0x13, 0x13, 0x14, 0x14, 0x15, 0x16, + 0x16, 0x17, 0x17, 0x18, 0x19, 0x19, 0x1A, 0x1A, 0x1B, 0x1C, 0x1C, 0x1D, + 0x1E, 0x1E, 0x1F, 0x20, 0x21, 0x21, 0x22, 0x23, 0x24, 0x24, 0x25, 0x26, + 0x27, 0x28, 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2E, 0x2F, 0x30, + 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, + 0x3D, 0x3E, 0x3F, 0x40, 0x41, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, + 0x4B, 0x4C, 0x4D, 0x4E, 0x50, 0x51, 0x52, 0x53, 0x55, 0x56, 0x57, 0x59, + 0x5A, 0x5B, 0x5D, 0x5E, 0x5F, 0x61, 0x62, 0x63, 0x65, 0x66, 0x68, 0x69, + 0x6B, 0x6C, 0x6E, 0x6F, 0x71, 0x72, 0x74, 0x75, 0x77, 0x79, 0x7A, 0x7C, + 0x7D, 0x7F, 0x81, 0x82, 0x84, 0x86, 0x87, 0x89, 0x8B, 0x8D, 0x8E, 0x90, + 0x92, 0x94, 0x96, 0x97, 0x99, 0x9B, 0x9D, 0x9F, 0xA1, 0xA3, 0xA5, 0xA6, + 0xA8, 0xAA, 0xAC, 0xAE, 0xB0, 0xB2, 0xB4, 0xB6, 0xB8, 0xBA, 0xBD, 0xBF, + 0xC1, 0xC3, 0xC5, 0xC7, 0xC9, 0xCC, 0xCE, 0xD0, 0xD2, 0xD4, 0xD7, 0xD9, + 0xDB, 0xDD, 0xE0, 0xE2, 0xE4, 0xE7, 0xE9, 0xEB, 0xEE, 0xF0, 0xF3, 0xF5, + 0xF8, 0xFA, 0xFD, 0xFF +}; + +/** + * Translation table from brightness to PWM setting to allow smooth + * fadings (16-bit timers). + */ +static const uint16_t pwm_table16[256] PROGMEM = { + 0x0000, 0x0000, 0x0000, 0x0001, 0x0002, 0x0004, 0x0006, 0x0008, 0x000B, + 0x000F, 0x0014, 0x0019, 0x001F, 0x0026, 0x002E, 0x0037, 0x0041, 0x004B, + 0x0057, 0x0063, 0x0071, 0x0080, 0x008F, 0x00A0, 0x00B2, 0x00C5, 0x00DA, + 0x00EF, 0x0106, 0x011E, 0x0137, 0x0152, 0x016E, 0x018B, 0x01A9, 0x01C9, + 0x01EB, 0x020E, 0x0232, 0x0257, 0x027F, 0x02A7, 0x02D2, 0x02FD, 0x032B, + 0x0359, 0x038A, 0x03BC, 0x03EF, 0x0425, 0x045C, 0x0494, 0x04CF, 0x050B, + 0x0548, 0x0588, 0x05C9, 0x060C, 0x0651, 0x0698, 0x06E0, 0x072A, 0x0776, + 0x07C4, 0x0814, 0x0866, 0x08B9, 0x090F, 0x0967, 0x09C0, 0x0A1B, 0x0A79, + 0x0AD8, 0x0B3A, 0x0B9D, 0x0C03, 0x0C6A, 0x0CD4, 0x0D3F, 0x0DAD, 0x0E1D, + 0x0E8F, 0x0F03, 0x0F79, 0x0FF2, 0x106C, 0x10E9, 0x1168, 0x11E9, 0x126C, + 0x12F2, 0x137A, 0x1404, 0x1490, 0x151F, 0x15B0, 0x1643, 0x16D9, 0x1771, + 0x180B, 0x18A7, 0x1946, 0x19E8, 0x1A8B, 0x1B32, 0x1BDA, 0x1C85, 0x1D33, + 0x1DE2, 0x1E95, 0x1F49, 0x2001, 0x20BB, 0x2177, 0x2236, 0x22F7, 0x23BB, + 0x2481, 0x254A, 0x2616, 0x26E4, 0x27B5, 0x2888, 0x295E, 0x2A36, 0x2B11, + 0x2BEF, 0x2CD0, 0x2DB3, 0x2E99, 0x2F81, 0x306D, 0x315A, 0x324B, 0x333F, + 0x3435, 0x352E, 0x3629, 0x3728, 0x3829, 0x392D, 0x3A33, 0x3B3D, 0x3C49, + 0x3D59, 0x3E6B, 0x3F80, 0x4097, 0x41B2, 0x42D0, 0x43F0, 0x4513, 0x463A, + 0x4763, 0x488F, 0x49BE, 0x4AF0, 0x4C25, 0x4D5D, 0x4E97, 0x4FD5, 0x5116, + 0x525A, 0x53A1, 0x54EB, 0x5638, 0x5787, 0x58DA, 0x5A31, 0x5B8A, 0x5CE6, + 0x5E45, 0x5FA7, 0x610D, 0x6276, 0x63E1, 0x6550, 0x66C2, 0x6837, 0x69AF, + 0x6B2B, 0x6CAA, 0x6E2B, 0x6FB0, 0x7139, 0x72C4, 0x7453, 0x75E5, 0x777A, + 0x7912, 0x7AAE, 0x7C4C, 0x7DEF, 0x7F94, 0x813D, 0x82E9, 0x8498, 0x864B, + 0x8801, 0x89BA, 0x8B76, 0x8D36, 0x8EFA, 0x90C0, 0x928A, 0x9458, 0x9629, + 0x97FD, 0x99D4, 0x9BB0, 0x9D8E, 0x9F70, 0xA155, 0xA33E, 0xA52A, 0xA71A, + 0xA90D, 0xAB04, 0xACFE, 0xAEFB, 0xB0FC, 0xB301, 0xB509, 0xB715, 0xB924, + 0xBB37, 0xBD4D, 0xBF67, 0xC184, 0xC3A5, 0xC5CA, 0xC7F2, 0xCA1E, 0xCC4D, + 0xCE80, 0xD0B7, 0xD2F1, 0xD52F, 0xD771, 0xD9B6, 0xDBFE, 0xDE4B, 0xE09B, + 0xE2EF, 0xE547, 0xE7A2, 0xEA01, 0xEC63, 0xEECA, 0xF134, 0xF3A2, 0xF613, + 0xF888, 0xFB02, 0xFD7E, 0xFFFF +}; + +/** + * Configure a PWM pin of Timer 0 (8-bit resolution). + * + * @note Timer 0 is used by tmk's timer module as well. + * You can therefore only temporarilly PWM-modulate using timer 0 + * (ie. NOT during matrix scanning), cannot use any timer module functions + * and should call timer_init() afterwards. + * This can be easily resolved by using pwm_pb5_set_led() for one of the LEDs + * and redistribute all the LED. + * The buzzer can then use the no longer used PD0 since it's manually + * IRQ-triggered anyway. + * + * @param channel Channel to initialize. + * 0 (OC0A/PB7), 1 (OC0B/PD0) + */ +static void pwm_timer0_init(uint8_t channel) +{ + /* Fast PWM on OC0x, inverted duty cycle, TOP = 0xFF */ + TCCR0A |= (0b11 << (3-channel)*2) | 0b11; + /* no prescaling */ + TCCR0B = 0b00000001; +} + +void pwm_pd0_set_led(uint8_t brightness) +{ + switch (brightness) { + case 0: + TCCR0A &= ~0b00110000; + PORTD |= (1 << PD0); + break; + case 255: + TCCR0A &= ~0b00110000; + PORTD &= ~(1 << PD0); + break; + default: + pwm_timer0_init(1); + OCR0B = pgm_read_byte(&pwm_table8[brightness]); + break; + } +} + +/** + * Configure a PWM pin of Timer 1 (16-bit resolution). + * + * @param channel Channel to initialize. + * 0 (OC1A/PB5), 1 (OC1B/PB6), 2 (OC1C/PB7) + */ +static void pwm_timer1_init(uint8_t channel) +{ + /* Fast PWM on OC1x, inverted duty cycle, TOP = ICR1 */ + TCCR1A |= (0b11 << (3-channel)*2) | 0b10; + /* stop timer */ + TCCR1B = 0; + /* TOP for PWM - full 16 Bit */ + ICR1 = 0xFFFF; + /* no prescaling */ + TCCR1B = 0b00011001; +} + +void pwm_pb5_set_led(uint8_t brightness) +{ + switch (brightness) { + case 0: + TCCR1A &= ~0b11000000; + PORTB |= (1 << PB5); + break; + case 255: + TCCR1A &= ~0b11000000; + PORTB &= ~(1 << PB5); + break; + default: + pwm_timer1_init(0); + OCR1A = pgm_read_word(&pwm_table16[brightness]); + break; + } +} + +void pwm_pb6_set_led(uint8_t brightness) +{ + switch (brightness) { + case 0: + TCCR1A &= ~0b00110000; + PORTB |= (1 << PB6); + break; + case 255: + TCCR1A &= ~0b00110000; + PORTB &= ~(1 << PB6); + break; + default: + pwm_timer1_init(1); + OCR1B = pgm_read_word(&pwm_table16[brightness]); + break; + } +} + +void pwm_pb7_set_led(uint8_t brightness) +{ + switch (brightness) { + case 0: + TCCR1A &= ~0b00001100; + PORTB |= (1 << PB7); + break; + case 255: + TCCR1A &= ~0b00001100; + PORTB &= ~(1 << PB7); + break; + default: + pwm_timer1_init(2); + OCR1C = pgm_read_word(&pwm_table16[brightness]); + break; + } +} + +/** + * Configure a PWM pin of Timer 2 (8-bit resolution). + * + * @param channel Channel to initialize. + * 0 (OC2A/PB4), 1 (OC2B/PD1) + */ +static void pwm_timer2_init(uint8_t channel) +{ + /* Fast PWM on OC2x, inverted duty cycle, TOP = 0xFF */ + TCCR2A |= (0b11 << (3-channel)*2) | 0b11; + /* no prescaling */ + TCCR2B = 0b00000001; +} + +void pwm_pb4_set_led(uint8_t brightness) +{ + switch (brightness) { + case 0: + TCCR2A &= ~0b11000000; + PORTB |= (1 << PB4); + break; + case 255: + TCCR2A &= ~0b11000000; + PORTB &= ~(1 << PB4); + break; + default: + pwm_timer2_init(0); + OCR2A = pgm_read_byte(&pwm_table8[brightness]); + break; + } +} + +void pwm_pd1_set_led(uint8_t brightness) +{ + switch (brightness) { + case 0: + TCCR2A &= ~0b00110000; + PORTD |= (1 << PD1); + break; + case 255: + TCCR2A &= ~0b00110000; + PORTD &= ~(1 << PD1); + break; + default: + pwm_timer2_init(1); + OCR2B = pgm_read_byte(&pwm_table8[brightness]); + break; + } +} + +/** + * Set a LED by position in the first row. + * + * @bug The pins used should be rescrambled after we freed PD0. + * + * @param led LED to set (0-4). + * @param brightness Brightness level to set. + */ +void pwm_set_led(uint8_t led, uint8_t brightness) +{ + switch (led) { + case 0: pwm_pd0_set_led(brightness); break; + case 1: pwm_pb7_set_led(brightness); break; + case 2: pwm_pd1_set_led(brightness); break; + case 3: pwm_pb6_set_led(brightness); break; + case 4: pwm_pb4_set_led(brightness); break; + } +} + +/** + * Play a tone on PB5 (the buzzer). + * + * @note This uses timer 3 with an IRQ, even though we cannot + * use one of the Timer 3 PWM pins -- they are required for matrix + * strobing. + * It was problematic to use one of the accessible Timer 0-2 pins as + * a frequency generator for the buzzer, though: + * - Timer 0 (PD0) does not support toggle mode and regular PWM mode would + * leave only a 7-bit frequency resolution. + * - Timer 1 is shared with two other LED pins. + * It is therefore not possible to use toggle mode, but the remaining 15 + * bit are sufficient anyway. Unfortunately, changing the frequency changes + * the timer's TOP value, which requires recalculating the duty cycles of the + * remaining two pins. This calculation is slow and cannot be cached. + * Also, changing the frequency would always introduce some flickering. + * - The same is true for timer 2, just with even less resolution. + * Using timer 3 exclusively for sound has the advantage that we can also + * some day use an IRQ for playing back (bit banging) audio samples eg. + * for a keyclick sounds. + * + * @todo It would be nice, if we could specify the tone's volume. + * This will reduce the effective resolution to 15 bit, but that should be + * sufficient anyway. + * + * @param freq Frequency to play. If 0, disables the buzzer. + */ +void pwm_pb5_set_tone(uint16_t freq) +{ + if (!freq) { + /* + * There should be a way to turn off the buzzer as we would otherwise + * always have some kind of tone. + */ + TIMSK3 = 0; + return; + } + + /* + * CTC mode: Effectively allows us to toggle the pin after OCR3A counts. + * This allows us to use the full 16-bit resolution. + * On the other hand, if we'd like to control volume, we'd have to + * control the cycle length independently, reducing resolution to 15 bit. + */ + TCCR3A = 0b00; + /* + * Prescaling: 8 (0b010). + * This allows for frequencies between 15 Hz and 1 MHz. + * + * FIXME: It may be even better to use 1 if we have frequencies below 122 Hz. + */ + TCCR3B = 0b00001010; + + /* + * The frequency of the resulting signal is calculated as follows: + * F_CPU / PRESCALER / (CYCLE_LENGTH+1) / 2 + */ + OCR3A = (F_CPU/2/8) / freq - 1; + + /* enable TIMER3_COMPA_vect() interrupt */ + TIMSK3 = (1 << OCIE3A); +} + +ISR(TIMER3_COMPA_vect, ISR_NOBLOCK) +{ + PORTB ^= (1 << PB5); +} -- cgit v1.2.3