#include <aversive.h>
+#include <aversive/wait.h>
struct servo {
uint8_t bit;
static struct servo servo_table[] = {
{
- .bit = 0,
- .command = 0,
+ .bit = 2,
+ .command = 300,
+ },
+ {
+ .bit = 3,
+ .command = 700,
},
{
- .bit = 1,
+ .bit = 4,
.command = 512,
},
{
- .bit = 2,
- .command = 1023,
+ .bit = 5,
+ .command = 512,
+ },
+ {
+ .bit = 6,
+ .command = 512,
+ },
+ {
+ .bit = 7,
+ .command = 512,
},
};
+#define NB_SERVO (sizeof(servo_table)/sizeof(*servo_table))
+
+static uint8_t bypass;
+static volatile uint8_t done;
+static uint8_t portval;
+static uint8_t rxidx;
+
+static uint8_t icp_idx = NB_SERVO;
+static uint16_t icp_servos[NB_SERVO];
+static uint16_t icp_prev;
+
+#define BYPASS_ENABLE 14
+#define BYPASS_DISABLE 15
-static volatile uint8_t rxbuf[16];
-register uint8_t rxlen asm("r2");
-register uint8_t done asm("r3");
-register uint8_t portval asm("r4");
-register uint8_t bypass asm("r5");
+#define LED_ON() do { PORTB |= 0x02; } while(0)
+#define LED_OFF() do { PORTB &= ~0x02; } while(0)
+
+/*
+ * SPI protocol:
+ *
+ * A command is stored on 2 bytes. The first one has its msb to 0, and the
+ * second one to 1. The first received byte contains the command number, and the
+ * msb of the servo value. The second byte contains the lsb of the servo value.
+ *
+ * Commands 0 to NB_SERVO are to set the value of servo.
+ * Command 14 is to enable bypass mode.
+ * Command 15 is to disable bypass mode.
+ */
+static union {
+ uint8_t u8;
+ struct {
+ /* inverted: little endian */
+ uint8_t val_msb:3;
+ uint8_t cmd_num:4;
+ uint8_t zero:1;
+ };
+} byte0;
+
+static union {
+ uint8_t u8;
+ struct {
+ /* inverted: little endian */
+ uint8_t val_lsb:7;
+ uint8_t one:1;
+ };
+} byte1;
SIGNAL(TIMER1_COMPA_vect)
{
- PORTC = portval;
+ PORTD = portval;
TIMSK1 &= ~_BV(OCIE1A);
done = 1;
}
static void poll_spi(void)
{
+ uint8_t c;
+
+ /* reception complete ? */
+ if (!(SPSR & (1<<SPIF)))
+ return;
+
+ c = SPDR;
+ if ((rxidx == 0) && (c & 0x80)) {
+ rxidx = 0;
+ return; /* drop */
+ }
+ if ((rxidx == 1) && ((c & 0x80) == 0)) {
+ rxidx = 0;
+ return; /* drop */
+ }
+
+ if (rxidx == 0) {
+ byte0.u8 = c;
+ }
+ else {
+ uint16_t val;
+
+ byte1.u8 = c;
+
+ /* process command */
+
+ if (byte0.cmd_num < NB_SERVO) {
+ val = (uint16_t)byte0.val_msb << 7;
+ val += byte1.val_lsb;
+ servo_table[byte0.cmd_num].command = val;
+ }
+ else if (byte0.cmd_num == BYPASS_ENABLE) {
+ bypass = 1;
+ }
+ else if (byte0.cmd_num == BYPASS_DISABLE) {
+ bypass = 0;
+ }
+ }
+
+ rxidx ^= 1;
+}
+
+static void poll_input_capture(void)
+{
+ uint16_t icp, diff;
+ uint8_t rising;
+
+ /* no new sample, return */
+ if ((TIFR1 & _BV(ICF1)) == 0)
+ return;
+
+ sei();
+ icp = ICR1;
+ cli();
+
+ rising = TCCR1B & _BV(ICES1);
+
+ /* change the edge type */
+ TCCR1B ^= _BV(ICES1);
+
+ /* clear the flag */
+ TIFR1 = TIFR1 | _BV(ICF1);
+
+ diff = icp - icp_prev;
+ icp_prev = icp;
+
+ /* a rising edge with at least 2ms of state 0 means that we
+ * get the first servo */
+ if (rising == 1 && diff > 2000) {
+ icp_idx = 0;
+ return;
+ }
+
+ /* get the value for the servo */
+ if (rising == 0 && icp_idx < NB_SERVO) {
+ if (diff < 1000)
+ icp_servos[icp_idx] = 0;
+ else
+ icp_servos[icp_idx] = diff - 1000;
+ icp_idx++;
+ }
+}
+
+static void poll(void)
+{
+ poll_spi();
+ poll_input_capture();
}
static void load_timer_at(uint16_t t)
//portval = PORTC | (1 << s->bit);
portval = (1 << s->bit);
t = TCNT1;
- load_timer_at(t + 150);
+ load_timer_at(t + 20);
while (done == 0)
- poll_spi();
+ poll();
/* reset bit */
done = 0;
portval = 0;
//portval = PORTC & (~(1 << s->bit));
- load_timer_at(t + 150 + 8000 + s->command * 8);
+ load_timer_at(t + 20 + 1000 + s->command);
while (done == 0)
- poll_spi();
+ poll();
}
int main(void)
{
uint8_t i;
uint8_t t, diff;
+ uint8_t tmp;
+
+ /* use pull-up for inputs */
+ PORTC |= 0x3f;
- DDRB = 0x20;
- DDRC = 0x7;
+ /* LED */
+ DDRB = 0x02;
- /* start timer1 at clk/1 (8Mhz) */
+#if 0 /* LED debug */
+ while (1) {
+ LED_ON();
+ wait_ms(100);
+ LED_OFF();
+ wait_ms(100);
+ }
+#endif
+
+ /* servo outputs PD2-PD7 */
+ DDRD = 0xfc;
+
+ /* start timer1 at clk/8 (1Mhz), enable noise canceler on
+ * input capture, capture rising edge */
TCNT1 = 0;
- TCCR1B = _BV(CS10);
+ TCCR1B = _BV(CS11) | _BV(ICNC1) | _BV(ICES1);
/* start timer0 at clk/1024 (~8Khz) */
TCNT0 = 0;
TCCR0B = _BV(CS02) | _BV(CS00);
+ /* enable spi (don't set unused MISO as output) */
+ SPCR = _BV(SPE);
+
sei();
+ bypass = 0;
while (1) {
t = TCNT0;
- for (i = 0; i < sizeof(servo_table)/sizeof(*servo_table); i++) {
+ for (i = 0; i < NB_SERVO; i++) {
do_one_servo(&servo_table[i]);
}
/* wait 20 ms */
diff = TCNT0 - t;
if (diff >= 160)
break;
- poll_spi();
+ poll();
}
/* bypass mode */
- while (bypass == 1) {
- PORTC = PORTB;
+ if (bypass == 1) {
+ LED_ON();
+
+ while (bypass == 1) {
+ tmp = PINC;
+ tmp &= 0x3f;
+ tmp <<= 2;
+ PORTD = tmp;
+ poll();
+ }
+ LED_OFF();
}
}
git.droids-corp.org / protos / rc_servos.git / blobdiff