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sorry 2bt... need to play the 8bit way

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This commit is contained in:
john stone 2012-08-14 22:53:25 +02:00
parent 96d7a0ed9d
commit 6e24129648
3 changed files with 25 additions and 31 deletions
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2
firmware/freq_table.h
View File

@ -1,5 +1,7 @@
#include <avr/pgmspace.h> #include <avr/pgmspace.h>
const uint16_t freq_table[] PROGMEM = { const uint16_t freq_table[] PROGMEM = {
/*0x00*/ 39, /*0x00*/ 39,
/*0x01*/ 41, /*0x01*/ 41,

12
firmware/main.c
View File

@ -70,8 +70,6 @@ static void init_leds(void)
/*enable interrupt*/ /*enable interrupt*/
TIMSK2 |= (1<<OCIE2A); TIMSK2 |= (1<<OCIE2A);
return; return;
} }
@ -88,12 +86,13 @@ static void init_motor(void)
/* vibration motor on B1, initially off: */ /* vibration motor on B1, initially off: */
DDRB |= (1 << PORTB1); DDRB |= (1 << PORTB1);
PORTB &= ~( 1<<PORTB1); PORTB &= ~( 1<<PORTB1);
return;
} }
int main(void) void __attribute__((noreturn))
main(void)
{ {
/* hardware initialisation: */ /* hardware initialisation: */
//init_leds(); //init_leds();
@ -120,12 +119,11 @@ int main(void)
USART0_crlf(); USART0_crlf();
//last_darkval=darkval; //last_darkval=darkval;
}; };
synth_poll();
//USART0_put_uint16(0xA09F); //USART0_put_uint16(0xA09F);
//USART0_crlf(); //USART0_crlf();
}; }
/* never */ return 0; /* never return 0; */
} }

40
firmware/synth.c
View File

@ -8,7 +8,8 @@
enum { enum {
channel_count = 3, channel_count = 3,
tick_length = 400, //tick_length = 400,
// tick_length = 256,
row_length = 4, row_length = 4,
pattern_length = 16 pattern_length = 16
}; };
@ -172,7 +173,7 @@ enum {
static synth_channel_t channels[channel_count]; static synth_channel_t channels[channel_count];
static int16_t sample; static int8_t sample;
static int8_t tick; static int8_t tick;
static int8_t row; static int8_t row;
static int8_t seq; static int8_t seq;
@ -181,10 +182,12 @@ static int8_t seq;
/* PROTOTYPES */ /* PROTOTYPES */
uint8_t synth_mix(void); uint8_t synth_mix(void);
static uint16_t timeslots[SYNTH_BUFSIZE]; static uint8_t timeslots[SYNTH_BUFSIZE];
static uint8_t timeslots_write; // current write head static uint8_t timeslots_write; // current write head
static uint8_t timeslots_read; // current read head static uint8_t timeslots_read; // current read head
uint8_t timeslots_fill;
/*register for atomic ++ and -- */
register uint8_t timeslots_fill asm("r2");
static void enqueue_timeslot(uint8_t synthval); static void enqueue_timeslot(uint8_t synthval);
@ -197,15 +200,12 @@ void synth_init(void)
row = 0; row = 0;
seq = 0; seq = 0;
timeslots_fill = 0; timeslots_fill = 0;
//prefill timeslot buffer
enqueue_timeslot(synth_mix());
enqueue_timeslot(synth_mix());
} }
uint8_t synth_mix(void) inline uint8_t synth_mix(void)
{ {
if(sample == 0) { // new tick if(sample == 0) { // new tick
for(int i = 0; i < channel_count; i++) { for(int i = 1; i < channel_count; i++) {
synth_channel_t* chan = &channels[i]; synth_channel_t* chan = &channels[i];
const synth_instrument_t* inst = &instruments[chan->inst_nr]; const synth_instrument_t* inst = &instruments[chan->inst_nr];
@ -215,12 +215,12 @@ uint8_t synth_mix(void)
chan->pulse_width += inst->pulse_sweep; chan->pulse_width += inst->pulse_sweep;
chan->pos++; chan->pos++;
if(wave_table[chan->pos][1] == 0xff) chan->pos += wave_table[chan->pos][0]; if(wave_table[chan->pos][1] == 0xff) chan->pos += wave_table[chan->pos][0];
// enter new row // enter new rol
// w
if(tick == 0) { if(tick == 0) {
uint8_t pattern_nr = pattern_table[seq][i]; uint8_t pattern_nr = pattern_table[seq][i];
uint8_t note = pgm_read_byte(&patterns[pattern_nr][row][0]); uint8_t note = pgm_read_byte(&patterns[pattern_nr][row][0]);
@ -240,8 +240,7 @@ uint8_t synth_mix(void)
} }
} }
} }
if(++sample == tick_length) { if(++sample == 0){
sample = 0;
if(++tick == row_length) { if(++tick == row_length) {
tick = 0; tick = 0;
if(++row == pattern_length) { if(++row == pattern_length) {
@ -257,7 +256,7 @@ uint8_t synth_mix(void)
uint8_t output = 0; uint8_t output = 0;
for(int i = 0; i < channel_count; i++) { for(int i = 0; i < channel_count; i++) {
synth_channel_t* chan = &channels[i]; synth_channel_t* chan = &channels[i];
const synth_instrument_t* inst = &instruments[chan->inst_nr]; // const synth_instrument_t* inst = &instruments[chan->inst_nr];
chan->phase += pgm_read_word(&freq_table[(uint8_t)(chan->note + wave_table[chan->pos][0])]); chan->phase += pgm_read_word(&freq_table[(uint8_t)(chan->note + wave_table[chan->pos][0])]);
@ -281,7 +280,7 @@ uint8_t synth_mix(void)
break; break;
} }
output += ((amp & 0xff) * chan->level) >> 8; output += (((amp & 0xff) * chan->level) >> 8);
} }
return output; return output;
@ -291,7 +290,8 @@ uint8_t synth_mix(void)
/* fill all the timeslots */ /* fill all the timeslots */
inline void synth_poll(void) { inline void synth_poll(void) {
/* refill timeslots queue */ /* refill timeslots queue */
while (timeslots_fill < (SYNTH_BUFSIZE-1)) // while (timeslots_fill < (SYNTH_BUFSIZE-1))
if (timeslots_fill < (SYNTH_BUFSIZE-1))
enqueue_timeslot(synth_mix()); enqueue_timeslot(synth_mix());
} }
@ -307,16 +307,10 @@ static inline uint8_t dequeue_timeslot() {
if(timeslots_fill){ if(timeslots_fill){
/* buffer not underrun... move forward in readbuffer */ /* buffer not underrun... move forward in readbuffer */
#if 1 /*debug */
PORTC = 0;
#endif
timeslots_fill --; timeslots_fill --;
timeslots_read ++; timeslots_read ++;
} else { /*buffer underrun. not moving forward*/
#if 1
PORTC = 0b00000001 ;
#endif
} }
return t; return t;
} }