/*

* Midipult software, atmega8535

*/

/* 15 + 18 = 33 knoepfe */

/* 56 potis */

#include <inttypes.h>

#include <avr/io.h>

#include <avr/interrupt.h>

#include <avr/signal.h>

#define F_CPU 12000000UL /* 12 Mhz */

#include <avr/delay.h>

/*** UART zeugs ***/

#define RB_SIZE 16

#define MIDI_BAUD 31250UL /* 31.25 kbps */

volatile char tx_buf[RB_SIZE];

volatile char tx_wr = 0, tx_rd = 0;

#define TX_INCR(a, b) (((a) + (b)) & (RB_SIZE - 1))

#define UART_TX_OK (UCSRA & _BV(UDRE))

#define TX_FREE (!(TX_INCR(tx_wr, 1) == tx_rd))

SIGNAL(SIG_UART_TRANS) {

PORTD ^= _BV(6);

if (tx_rd != tx_wr) {

UDR = tx_buf[tx_rd];

tx_rd = TX_INCR(tx_rd, 1);

}

}

void uart_putc(char c) {

if (UART_TX_OK && (tx_wr == tx_rd)) {

UDR = c;

} else {

while (TX_INCR(tx_wr, 1) == tx_rd) ;

tx_buf[tx_wr] = c;

tx_wr = TX_INCR(tx_wr, 1);

}

}

void uart_init(void) {

tx_wr = tx_rd = 0;

/* set baudrate */

UBRRL = (((F_CPU) / (16 * MIDI_BAUD)) - 1);

/* enable TX, interrupts */

UCSRB = _BV(TXEN) | _BV(TXCIE);

sei();

}

/*** UART zeugs ***/

void io_init(void) {

/* disable watchdog */

WDTCR = 0;

/* DD = 1, output */

/* PORT = 1 wenn DD = 0, dann pull-up */

/* portd = output */

DDRD = 0XFF;

/* enable ADC */

DDRA = 0;

PORTA = 0xFF;

ADMUX = _BV(ADLAR);

ADCSRA = _BV(ADEN)|_BV(ADPS2)|_BV(ADPS1)|_BV(ADPS0);

// ADCSRA = _BV(ADEN);

uart_init();

}

/*** MIDI zeugs ***/

#define MIDI_NOTE_ON 0x9

#define MIDI_NOTE_OFF 0x8

#define MIDI_AFTERTOUCH 0xA

#define MIDI_CC 0xB

#define MIDI_PROG_CHANGE 0xC

#define MIDI_CHAN_PRESS 0xD

#define MIDI_PITCH_WHEEL 0xE

#define MIDI_STATUS_TYPE(c) (((c) & 0xF0) >> 4)

#define MIDI_STATUS_CHAN(c) ((c) & 0xF)

static inline midi_is_status(char c) {

return (c & 0x80);

}

void midi_send_note_on(unsigned char channel, unsigned char note, unsigned char velocity) {

uart_putc((MIDI_NOTE_ON << 4) | channel);

uart_putc(note);

uart_putc(velocity);

}

void midi_send_note_off(unsigned char channel, unsigned char note, unsigned char velocity) {

uart_putc((MIDI_NOTE_OFF << 4) | channel);

uart_putc(note);

uart_putc(velocity);

}

void midi_send_cc(unsigned char channel, unsigned char controller, unsigned char value) {

uart_putc((MIDI_CC << 4) | channel);

uart_putc(controller);

uart_putc(value);

}

/*** knoepfe und LEDs ***/

#define LED_BUTTON_SEL_PORT C

#define PORTLED_BUTTON_SEL_PORT PORTC

#define DDRLED_BUTTON_SEL_PORT DDRC

#define LED_BUTTON_PORT D

#define PORTLED_BUTTON_PORT PORTD

#define DDRLED_BUTTON_PORT DDRD

#define PINLED_BUTTON_PORT PIND

#define SET_PIN_OUTPUT(port, pin) { DDR ## port |= _BV(pin); }

#define SET_PIN_INPUT(port, pin) { DDR ## port &= ~(_BV(pin)); }

#define SET_PIN_INPUT_PULLUP(port, pin) { SET_PIN_INPUT(port, pin); PORT ## port |= _BV(pin); }

#define SET_PIN_LOW(port, pin) { PORT ## port &= ~(_BV(pin)); }

#define SET_PIN_HIGH(port, pin) { PORT ## port |= _BV(pin); }

#define PIN_VALUE(port, pin) ((PIN ## port & _BV(pin)) ? 1 : 0)

#define NUM_BUTTONS 30

#define BUTTON_STATUS(i) (button_status[(i)] & 0xF)

#define SET_BUTTON_STATUS(i, val) { button_status[(i)] = button_status[(i)] & 0xF0 | (val); }

#define LED_STATUS(i) ((button_status[(i)] >> 4) & 0xF)

#define SET_LED_STATUS(i, val) { button_status[(i)] = button_status[(i)] & 0xF | ((val) << 4); }

#define BUTTON_NOTHING 0

#define BUTTON_PRESSED 1

#define BUTTON_NORMAL 2

#define BUTTON_RELEASED 3

/* debounce:

2 bits pro knopf

0 -> 1 (bounce?) -> 2

wenn knopf auf 1 dann nachricht senden (note on), wieder auf 0 (note off)

*/

#define BUTTON_ROWS 5

unsigned char button_status[BUTTON_ROWS * 8];

void init_buttons(void) {

int i, j;

for (i = 0; i < BUTTON_ROWS; i++)

for (j = 0; j < 8; j++)

button_status[i + j * BUTTON_ROWS] = BUTTON_NOTHING;

}

void ask_button(unsigned char button_pin, unsigned char sel_pin) {

SET_PIN_LOW(LED_BUTTON_SEL_PORT, sel_pin);

SET_PIN_INPUT_PULLUP(LED_BUTTON_PORT, button_pin + 2);

unsigned char val = PIN_VALUE(LED_BUTTON_PORT, button_pin + 2);

SET_PIN_HIGH(LED_BUTTON_SEL_PORT, sel_pin);

unsigned char button = sel_pin * BUTTON_ROWS + button_pin;

switch (button_status[button]) {

case BUTTON_NOTHING:

if (!val)

button_status[button] = BUTTON_PRESSED;

break;

case BUTTON_PRESSED:

case BUTTON_NORMAL:

if (val)

button_status[button] = BUTTON_RELEASED;

break;

case BUTTON_RELEASED:

if (val)

button_status[button] = BUTTON_NOTHING;

else

button_status[button] = BUTTON_PRESSED;

break;

}

}

void ask_buttons(void) {

int i, j;

/* all high */

DDRLED_BUTTON_SEL_PORT = 0xFF;

PORTLED_BUTTON_SEL_PORT = 0xFF;

for (i = 0; i < BUTTON_ROWS; i++)

for (j = 0; j < 8; j++)

ask_button(i, j);

}

void midi_buttons(void) {

int i, j;

for (i = 0; i < BUTTON_ROWS; i++)

for (j = 0; j < 8; j++) {

unsigned char button = i + j * BUTTON_ROWS;

switch (button_status[button]) {

case BUTTON_NOTHING:

case BUTTON_NORMAL:

break;

case BUTTON_PRESSED:

midi_send_note_on(1, 30 + button, 128);

button_status[button] = BUTTON_NORMAL;

// _delay_ms(10);

break;

case BUTTON_RELEASED:

midi_send_note_off(1, 30 + button, 128);

button_status[button] = BUTTON_NOTHING;

// _delay_ms(10);

break;

}

}

}

#if 0

void set_led(unsigned char sel_pin, unsigned char led_pin) {

SET_PIN_OUTPUT(LED_BUTTON_PORT, led_pin);

SET_PIN_LOW(LED_BUTTON_PORT, led_pin);

SET_PIN_OUTPUT(LED_BUTTON_SEL_PORT, sel_pin);

if (LED_STATUS(sel_pin * led_pin)) {

SET_PIN_HIGH(LED_BUTTON_SEL_PORT, sel_pin);

} else {

SET_PIN_LOW(LED_BUTTON_SEL_PORT, sel_pin);

}

}

void set_leds(void) {

int i, j;

for (i = 0; i < 6; i++)

for (j = 0; j < 8; j++)

set_led(i, j);

}

#endif

/*** ADCs ***/

#define POTI_SEL_PORT B

#define PORTPOTI_SEL_PORT PORTB

#define DDRPOTI_SEL_PORT DDRB

#define NUM_POTIS 64

unsigned char poti_status[NUM_POTIS];

void init_potis(void) {

int i, j;

for (i = 0; i < 8; i++)

for (j = 0; j < 8; j++)

poti_status[i * 8 + j] = 0x00;

}

volatile unsigned short last_adc;

#define MIN_THRESHOLD 0x2100

#define MAX_THRESHOLD 0xF000

unsigned char convert_to_cc(unsigned short adc) {

if (adc < MIN_THRESHOLD) return 0;

if (adc > MAX_THRESHOLD) return 0x7F;

uint32_t bla = (uint32_t)((uint32_t)adc - (uint32_t)MIN_THRESHOLD);

bla *= 0x7F;

bla /= 0xDFF0;

return bla;

}

void ask_poti(unsigned char sel_pin, unsigned char adc) {

SET_PIN_LOW(POTI_SEL_PORT, sel_pin);

_delay_us(50);

ADMUX = _BV(ADLAR) | adc;

ADCSRA |= _BV(ADSC);

loop_until_bit_is_set(ADCSRA, ADIF);

loop_until_bit_is_clear(ADCSRA, ADSC);

last_adc = ADC;

SET_PIN_HIGH(POTI_SEL_PORT, sel_pin);

unsigned char val = convert_to_cc(last_adc);

unsigned char poti = sel_pin + 8 * adc;

unsigned char old = poti_status[poti] & 0x7f;

if ((val != old) && ((val == 00) || (val == 0x7F) || (abs(val - old) > 1)))

poti_status[poti] = 0x80 | val;

}

void ask_potis(void) {

int i, j;

DDRPOTI_SEL_PORT = 0xFF;

PORTPOTI_SEL_PORT = 0xFF;

for (i = 0; i < 8; i++)

for (j = 0; j < 8; j++)

ask_poti(i, j);

}

void midi_potis(void) {

int i, j;

for (i = 0; i < 8; i++)

for (j = 0; j < 8; j++) {

unsigned char poti = i * 8 + j;

if (poti_status[poti] & 0x80) {

midi_send_cc(1, poti, poti_status[poti] & 0x7F);

poti_status[poti] &= 0x7F;

}

}

}

/*** Main ***/

int main(void) {

io_init();

init_buttons();

init_potis();

DDRPOTI_SEL_PORT = 0xFF;

PORTPOTI_SEL_PORT = 0xFF;

DDRA = 0x00;

PORTA = 0xFF;

ADMUX = 0;

int i;

for (i =0 ; i < 100; i++) {

ask_buttons();

ask_potis();

}

for (;;) {

ask_buttons();

midi_buttons();

ask_potis();

midi_potis();

}

}