X-Git-Url: http://git.droids-corp.org/?a=blobdiff_plain;f=main.c;h=82739b098a90a178ea284306fad53e127a9589e8;hb=31b666597c0014c64be6230df6451ec062524522;hp=53fd747dc8b45f40a82bc523c3e4045ec2901f97;hpb=e3f43b953a1103fa4e9f4f932a04e8ab51b3b884;p=protos%2Frc_servos.git

diff --git a/main.c b/main.c
index 53fd747..82739b0 100644
--- a/main.c
+++ b/main.c
@@ -1,4 +1,5 @@
 #include <aversive.h>
+#include <aversive/wait.h>
 
 struct servo {
 	uint8_t bit;
@@ -7,34 +8,173 @@ struct servo {
 
 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)
@@ -52,40 +192,61 @@ static void do_one_servo(struct servo *s)
 	//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 */
@@ -93,11 +254,20 @@ int main(void)
 			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();
 		}
 	}