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authorNicolas Schodet2008-04-15 00:30:44 +0200
committerNicolas Schodet2008-04-15 00:30:44 +0200
commite83202bcbb8dc8b3a00731cfdcd935344bba5e32 (patch)
tree76f4d83174ca9236e2c7c361f3e398a1a57729b9 /digital/io
parent6e5b93c8ad9d026cdce85f8b2b908533c2952aaf (diff)
* digital/io/src:
- fixed bad integer computation: 20 / 1000 = 0. - fixed no support for more than 5 servos. - added zero value support. - added saturation to protect from bad commands.
Diffstat (limited to 'digital/io')
-rw-r--r--digital/io/src/servo.avr.c21
-rw-r--r--digital/io/src/servo.h18
2 files changed, 25 insertions, 14 deletions
diff --git a/digital/io/src/servo.avr.c b/digital/io/src/servo.avr.c
index c2603c6e..39886bc5 100644
--- a/digital/io/src/servo.avr.c
+++ b/digital/io/src/servo.avr.c
@@ -56,7 +56,7 @@
* We want a time of 20ms (20/1000).
* See @a servo_init to know the prescaler value of the timer/counter.
*/
-static const uint16_t servo_tic_cyle_ = ((20/1000) * AC_FREQ / 256);
+static const uint16_t servo_tic_cyle_ = AC_FREQ / 256 * 20 / 1000;
/** @} */
@@ -90,11 +90,7 @@ void
servo_init (void)
{
/* Set-up all the pins of the servo to out direction */
- set_bit (SERVO_DDR, 0);
- set_bit (SERVO_DDR, 1);
- set_bit (SERVO_DDR, 2);
- set_bit (SERVO_DDR, 3);
- set_bit (SERVO_DDR, 4);
+ SERVO_DDR = 0xff;
/* All pins are at low state by default */
/* Set-up the timer/counter 2:
@@ -113,10 +109,13 @@ servo_init (void)
void
servo_set_high_time (uint8_t servo, uint8_t high_time)
{
+ uint8_t filtered = high_time;
+ if (filtered != 0)
+ UTILS_BOUND (filtered, SERVO_HIGH_TIME_MIN, SERVO_HIGH_TIME_MAX);
/* Sanity check */
if (servo < SERVO_NUMBER)
/* Set new desired position (high value time) */
- servo_high_time_[servo] = high_time;
+ servo_high_time_[servo] = filtered;
}
/* Get the high time of the servo. */
@@ -147,14 +146,18 @@ SIGNAL (SIG_OVERFLOW2)
case 2:
case 3:
case 4:
+ case 5:
+ case 6:
+ case 7:
/* Servos motor high state mode */
/* Set to low state the previous servo motor pin if needed (not for
* the first one) */
if (servo_updating_id_ != 0)
SERVO_PORT &= ~_BV (servo_updating_id_ - 1);
- /* Set to high state the current servo motor pin */
- set_bit (SERVO_PORT, servo_updating_id_);
+ /* Set to high state the current servo motor pin, unless is zero */
+ if (servo_high_time_[servo_updating_id_])
+ set_bit (SERVO_PORT, servo_updating_id_);
/* Plan next timer overflow to the TOP minus the current configuration
* of the servo motor */
TCNT2 = SERVO_TCNT_TOP - servo_high_time_[servo_updating_id_];
diff --git a/digital/io/src/servo.h b/digital/io/src/servo.h
index c6c08ce3..2b01e731 100644
--- a/digital/io/src/servo.h
+++ b/digital/io/src/servo.h
@@ -36,7 +36,7 @@
*
* Servo motors can be controlled by the time the input signal spend at its
* high state. For example, if the signal sent to the servo motor only spend
- * 0.5ms at the high state, it will have a 0 angle position. If the signal
+ * 1ms at the high state, it will have a 0 angle position. If the signal
* stays for 1.5ms at high state, it will have a 90 angle position.
* To manage all servo motors in a "one time shot", we need to use the
* timer/counter 2 of the ATmega128 and its overflow.
@@ -56,12 +56,19 @@
#define SERVO_NUMBER 6
/**
+ * Minimum high time for servos.
+ */
+#define SERVO_HIGH_TIME_MIN 0x24
+
+/**
+ * Maximum high time for servos.
+ */
+#define SERVO_HIGH_TIME_MAX 0x88
+
+/**
* Initialize servo module.
* This functions put the pins of the servos motor in the right direction,
* initialize the timer/counter 2 and some internals stuff.
- * A important remark: you need to set the default values of each servos motor
- * before calling this functions if you do not want to have some strange
- * behavior.
*/
void
servo_init (void);
@@ -70,7 +77,8 @@ servo_init (void);
* Set the high time of the input signal of a servo (and its position).
* @param servo the servo to change the position.
* @param high_time the high time we want the input signal to spend at the
- * high state to set the servo motor to a position.
+ * high state to set the servo motor to a position. A zero will let the servo
+ * floating.
*/
void
servo_set_high_time (uint8_t servo, uint8_t high_time);