From: Olivier Matz <zer0@droids-corp.org>
Date: Thu, 3 Oct 2013 18:11:24 +0000 (+0200)
Subject: poll input capture register
X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=31b666597c0014c64be6230df6451ec062524522;p=protos%2Frc_servos.git

poll input capture register

currently value are not send through spi, only saved in ram

Signed-off-by: Olivier Matz <zer0@droids-corp.org>
---

diff --git a/main.c b/main.c
index 3509874..82739b0 100644
--- a/main.c
+++ b/main.c
@@ -39,6 +39,10 @@ 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
 
@@ -126,6 +130,53 @@ static void poll_spi(void)
 	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)
 {
 	OCR1A = t;
@@ -143,7 +194,7 @@ static void do_one_servo(struct servo *s)
 	t = TCNT1;
 	load_timer_at(t + 20);
 	while (done == 0)
-		poll_spi();
+		poll();
 
 	/* reset bit */
 	done = 0;
@@ -151,7 +202,7 @@ static void do_one_servo(struct servo *s)
 	//portval = PORTC & (~(1 << s->bit));
 	load_timer_at(t + 20 + 1000 + s->command);
 	while (done == 0)
-		poll_spi();
+		poll();
 }
 
 int main(void)
@@ -178,9 +229,10 @@ int main(void)
 	/* servo outputs PD2-PD7 */
 	DDRD = 0xfc;
 
-	/* start timer1 at clk/8 (1Mhz) */
+	/* start timer1 at clk/8 (1Mhz), enable noise canceler on
+	 * input capture, capture rising edge */
 	TCNT1 = 0;
-	TCCR1B = _BV(CS11);
+	TCCR1B = _BV(CS11) | _BV(ICNC1) | _BV(ICES1);
 
 	/* start timer0 at clk/1024 (~8Khz) */
 	TCNT0 = 0;
@@ -202,7 +254,7 @@ int main(void)
 			diff = TCNT0 - t;
 			if (diff >= 160)
 				break;
-			poll_spi();
+			poll();
 		}
 		/* bypass mode */
 		if (bypass == 1) {
@@ -213,7 +265,7 @@ int main(void)
 				tmp &= 0x3f;
 				tmp <<= 2;
 				PORTD = tmp;
-				poll_spi();
+				poll();
 			}
 			LED_OFF();
 		}