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authorLars-Dominik Braun <lars@6xq.net>2015-02-26 14:39:30 +0100
committerLars-Dominik Braun <lars@6xq.net>2015-02-26 14:46:23 +0100
commite2e3038c627ea7460915cdd535cb91301af614a7 (patch)
tree392efd367176e57696eac7d21674b262f0cc7997
parent1a73da01d68d743d795830a6f7f36a083c7b6ed2 (diff)
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accel: Stop polling
Use freefall interrupts instead. This drop the fancy horizon/shake detection algorithms, but it works surprisingly well and is way more energy-efficient. Shake detection is a little too sensitive imo and horizon detection needs some tweaking too.
-rw-r--r--accel.c254
-rw-r--r--accel.h6
-rw-r--r--common.h9
-rw-r--r--ui.c18
4 files changed, 133 insertions, 154 deletions
diff --git a/accel.c b/accel.c
index 6dcb5c9..1bef646 100644
--- a/accel.c
+++ b/accel.c
@@ -1,3 +1,9 @@
+/* We use two freefall wakup thresholds:
+ * 1) Shake detection with >= 127 (~2g), actual value is ignored
+ * 2) Horizon detection with <= 60 (~1g) for 100ms, if the interrupt is
+ * asserted the actual value has to be read to determine the horizon
+ */
+
#include "common.h"
#include <stdio.h>
@@ -17,66 +23,55 @@
#define LIS302DL_WHOAMI 0xf
#define LIS302DL_CTRLREG1 0x20
#define LIS302DL_CTRLREG2 0x21
+#define LIS302DL_CTRLREG3 0x22
#define LIS302DL_UNUSED1 0x28
#define LIS302DL_OUTZ 0x2D
+#define LIS302DL_FFWUCFG1 0x30
+#define LIS302DL_FFWUTHS1 0x32
+#define LIS302DL_FFWUCFG2 0x34
+#define LIS302DL_FFWUTHS2 0x36
-/* value for 1g with +-2g max; measured */
-#define ACCEL_1G (55)
-/* offset for horizon detection */
-#define ACCEL_1G_OFF (5)
-/* threshold starting shake detection */
-#define ACCEL_SHAKE_START (90)
-/* difference prev and current value to get the current one registered as peak */
-#define ACCEL_SHAKE_REGISTER (120)
-/* 100ms for 100Hz data rate */
-#define ACCEL_SHAKE_TIMEOUT (10)
-
-/* z value */
-static int8_t zval = 0;
-static int16_t zvalnormal = 0;
-
-/* number of times shaken (i.e. peak level measured) */
+static int8_t zval;
static uint8_t shakeCount = 0;
-/* if max in one direction direction has been detected give it some time to
- * wait for max in the other direction */
-static uint8_t shakeTimeout = 0;
-static int16_t prevShakeVal = 0;
-static uint8_t peakCount = 0;
-static horizon shakeHorizon = HORIZON_NONE;
/* horizon position */
/* current */
static horizon horizonSign = HORIZON_NONE;
-/* how long has sign been stable? */
-static uint8_t horizonStable = 0;
-/* previous measurement */
-static horizon horizonPrevSign = HORIZON_NONE;
+static bool horizonChanged = false;
/* driver state */
#define STOPPED 0
#define START_REQUEST 1
-#define STARTING 2
-#define STOP_REQUEST 3
-#define STOPPING 4
-#define READING 5
-#define IDLE 6
+#define STARTING_A 2
+#define STARTING_B 3
+#define STARTING_C 4
+#define STARTING_D 5
+#define STARTING_E 6
+#define STARTING_F 7
+#define STOP_REQUEST 8
+#define STOPPING 9
+#define READING 10
+#define IDLE 11
static uint8_t state = STOPPED;
/* data ready interrupt
*/
ISR(PCINT1_vect) {
- const bool interrupt = (PINC >> PINC1) & 0x1;
- /* high-active */
- if (interrupt) {
- enableWakeup (WAKE_ACCEL);
- } else {
- disableWakeup (WAKE_ACCEL);
+ const uint8_t pin = PINC;
+ /* low-active */
+ const bool int1 = !((pin >> PINC0) & 0x1);
+ const bool int2 = !((pin >> PINC1) & 0x1);
+ if (int1) {
+ enableWakeup (WAKE_ACCEL_HORIZON);
+ }
+ if (int2) {
+ enableWakeup (WAKE_ACCEL_SHAKE);
}
}
void accelInit () {
/* set interrupt lines to input */
- DDRC = DDRC & ~((1 << DDC0) | (1 << DDC1));
+ DDRC &= ~((1 << DDC0) | (1 << DDC1));
/* enable interrupt PCI1 for PCINT8/9 */
PCICR = PCICR | (1 << PCIE1);
/* enable interrupts from port PC0/PC1 aka PCINT8/PCINT9 */
@@ -86,72 +81,6 @@ void accelInit () {
void accelStart () {
assert (state == STOPPED);
state = START_REQUEST;
-
-}
-
-/* register shake gesture
- *
- * “shake” means three peaks in directions 1, -1, 1
- */
-static void accelProcessShake () {
- if (shakeTimeout > 0) {
- --shakeTimeout;
- if (horizonSign != shakeHorizon) {
- /* ignore if horizon changed */
- shakeTimeout = 0;
- prevShakeVal = 0;
- peakCount = 0;
- } else if (sign (prevShakeVal) != sign (zvalnormal) &&
- abs (prevShakeVal - zvalnormal) >= ACCEL_SHAKE_REGISTER) {
- ++peakCount;
- shakeTimeout = ACCEL_SHAKE_TIMEOUT;
- prevShakeVal = zvalnormal;
- } else if (sign (prevShakeVal) == sign (zvalnormal) &&
- abs (zvalnormal) >= abs (prevShakeVal)) {
- /* actually we did not measure the peak yet/are still experiencing it */
- prevShakeVal = zvalnormal;
- shakeTimeout = ACCEL_SHAKE_TIMEOUT;
- }
- if (shakeTimeout == 0) {
- /* just timed out, can register gesture now */
- shakeCount += peakCount/2;
- prevShakeVal = 0;
- peakCount = 0;
- }
- }
-
- /* start shake detection */
- if (shakeTimeout == 0 && abs (zvalnormal) >= ACCEL_SHAKE_START) {
- shakeTimeout = ACCEL_SHAKE_TIMEOUT;
- peakCount = 1;
- prevShakeVal = zvalnormal;
- shakeHorizon = horizonSign;
- }
-}
-
-/* register horizon change
- *
- * i.e. have we been turned upside down?
- */
-static void accelProcessHorizon () {
- /* measuring approximately 1g */
- if (zval > (ACCEL_1G - ACCEL_1G_OFF) &&
- zval < (ACCEL_1G + ACCEL_1G_OFF) &&
- horizonPrevSign == HORIZON_POS && horizonSign != HORIZON_POS) {
- ++horizonStable;
- } else if (zval < (-ACCEL_1G + ACCEL_1G_OFF)
- && zval > (-ACCEL_1G - ACCEL_1G_OFF) &&
- horizonPrevSign == HORIZON_NEG && horizonSign != HORIZON_NEG) {
- ++horizonStable;
- } else {
- horizonStable = 0;
- }
- /* make sure its not just shaking */
- if (horizonStable > 5) {
- horizonSign = horizonPrevSign;
- horizonStable = 0;
- }
- horizonPrevSign = zval >= 0 ? HORIZON_POS : HORIZON_NEG;
}
void accelProcess () {
@@ -159,50 +88,119 @@ void accelProcess () {
case START_REQUEST: {
/* configuration:
* disable power-down-mode, enable z-axis
- * defaults
- * push-pull, high-active, data ready interrupt on int2
*/
- static uint8_t data[] = {0b01000100, 0b0, 0b00100000};
+ static uint8_t data[] = {0b01000100};
+
+ if (twRequest (TWM_WRITE, LIS302DL, LIS302DL_CTRLREG1, data,
+ sizeof (data)/sizeof (*data))) {
+ state = STARTING_A;
+ }
+ break;
+ }
+
+ /* set up ff_wu_1 (horizon detection) */
+ case STARTING_A: {
+ puts ("setting thresh wu1");
+ /* threshold 60 (~1g), duration 100ms (10 steps at 10ms) */
+ static uint8_t data[] = {0b00111100, 0b1010};
+ if (twRequest (TWM_WRITE, LIS302DL, LIS302DL_FFWUTHS1, data,
+ sizeof (data)/sizeof (*data))) {
+ state = STARTING_B;
+ }
+ break;
+ }
+
+ case STARTING_B:
+ if (shouldWakeup (WAKE_I2C)) {
+ disableWakeup (WAKE_I2C);
+ puts ("setting events wu1");
+ /* or events, enable interrupt on z low event */
+ static uint8_t data[] = {0b00010000};
+ if (twRequest (TWM_WRITE, LIS302DL, LIS302DL_FFWUCFG1, data,
+ sizeof (data)/sizeof (*data))) {
+ state = STARTING_C;
+ }
+ }
+ break;
- const bool ret = twRequest (TWM_WRITE, LIS302DL, LIS302DL_CTRLREG1, data,
- sizeof (data)/sizeof (*data));
- if (ret) {
- state = STARTING;
+ /* set up ff_wu_2 (shake detection) */
+ case STARTING_C: {
+ puts ("setting thresh wu2");
+ /* threshold 127 (~2g) (duration, next register, not modified) */
+ static uint8_t data[] = {0b01111111};
+ if (twRequest (TWM_WRITE, LIS302DL, LIS302DL_FFWUTHS2, data,
+ sizeof (data)/sizeof (*data))) {
+ state = STARTING_D;
}
break;
}
- case STARTING:
+ case STARTING_D:
+ if (shouldWakeup (WAKE_I2C)) {
+ disableWakeup (WAKE_I2C);
+ puts ("setting events wu2");
+ /* or events, enable interrupt on z high event (+/-) */
+ static uint8_t data[] = {0b00100000};
+ if (twRequest (TWM_WRITE, LIS302DL, LIS302DL_FFWUCFG2, data,
+ sizeof (data)/sizeof (*data))) {
+ state = STARTING_E;
+ }
+ }
+ break;
+
+ case STARTING_E:
+ if (shouldWakeup (WAKE_I2C)) {
+ disableWakeup (WAKE_I2C);
+ puts ("setting int");
+ /* push-pull, low-active, FF_WU_1 on int1, FF_WU_2 on int2 */
+ static uint8_t data[] = {0b10010001};
+ if (twRequest (TWM_WRITE, LIS302DL, LIS302DL_CTRLREG3, data,
+ sizeof (data)/sizeof (*data))) {
+ state = STARTING_F;
+ }
+ }
+ break;
+
+ case STARTING_F:
if (shouldWakeup (WAKE_I2C)) {
disableWakeup (WAKE_I2C);
+ puts ("ffwu setup done");
state = IDLE;
}
break;
case IDLE:
/* new data available in device buffer and bus is free */
- if (shouldWakeup (WAKE_ACCEL) && twRequest (TWM_READ, LIS302DL,
+ if (shouldWakeup (WAKE_ACCEL_HORIZON) && twRequest (TWM_READ, LIS302DL,
LIS302DL_OUTZ, (uint8_t *) &zval, sizeof (zval))) {
+ disableWakeup (WAKE_ACCEL_HORIZON);
state = READING;
}
+ if (shouldWakeup (WAKE_ACCEL_SHAKE)) {
+ disableWakeup (WAKE_ACCEL_SHAKE);
+ ++shakeCount;
+ }
break;
case READING:
if (shouldWakeup (WAKE_I2C)) {
disableWakeup (WAKE_I2C);
- state = IDLE;
/* the bus might be in use again already */
//assert (twr.status == TWST_OK);
- accelProcessHorizon ();
- /* calculate normalized z (i.e. without earth gravity component) */
- if (horizonSign == HORIZON_NEG) {
- zvalnormal = zval - (-ACCEL_1G);
- } else if (horizonSign == HORIZON_POS) {
- zvalnormal = zval - ACCEL_1G;
+ if (zval >= 0) {
+ if (horizonSign == HORIZON_NEG) {
+ horizonChanged = true;
+ }
+ horizonSign = HORIZON_POS;
+ } else {
+ if (horizonSign == HORIZON_POS) {
+ horizonChanged = true;
+ }
+ horizonSign = HORIZON_NEG;
}
- accelProcessShake ();
+ state = IDLE;
}
break;
@@ -212,12 +210,10 @@ void accelProcess () {
}
}
-int8_t accelGetZ () {
- return zval;
-}
-
-int8_t accelGetNormalizedZ () {
- return zvalnormal;
+horizon accelGetHorizon (bool * const changed) {
+ *changed = horizonChanged;
+ horizonChanged = false;
+ return horizonSign;
}
uint8_t accelGetShakeCount () {
@@ -228,7 +224,3 @@ void accelResetShakeCount () {
shakeCount = 0;
}
-horizon accelGetHorizon () {
- return horizonSign;
-}
-
diff --git a/accel.h b/accel.h
index edb2540..fcaaafd 100644
--- a/accel.h
+++ b/accel.h
@@ -13,11 +13,9 @@ typedef uint8_t horizon;
void accelInit ();
void accelStart ();
void accelProcess ();
-int8_t accelGetZ ();
-int8_t accelGetNormalizedZ ();
-uint8_t accelGetShakeCount ();
+horizon accelGetHorizon (bool * const);
void accelResetShakeCount ();
-horizon accelGetHorizon ();
+uint8_t accelGetShakeCount ();
#endif /* ACCEL_H */
diff --git a/common.h b/common.h
index 5730f47..028817c 100644
--- a/common.h
+++ b/common.h
@@ -27,10 +27,11 @@
extern volatile uint8_t wakeup;
/* wakeup sources */
-#define WAKE_ACCEL 0
-#define WAKE_GYRO 1
-#define WAKE_I2C 2
-#define WAKE_TIMER 3
+#define WAKE_ACCEL_HORIZON 0
+#define WAKE_ACCEL_SHAKE 1
+#define WAKE_GYRO 2
+#define WAKE_I2C 3
+#define WAKE_TIMER 4
#define shouldWakeup(x) (wakeup & (1 << x))
#define enableWakeup(x) wakeup |= 1 << x;
diff --git a/ui.c b/ui.c
index 0d95751..f9e478d 100644
--- a/ui.c
+++ b/ui.c
@@ -461,21 +461,10 @@ void uiLoop () {
accelStart ();
pwmSet (1, PWM_OFF);
- /* make sure data is read even when missing the first interrupt (i.e.
- * reboot) */
- enableWakeup (WAKE_ACCEL);
- enableWakeup (WAKE_GYRO);
-
while (1) {
processSensors ();
- horizon newh = accelGetHorizon ();
- if (newh != h) {
- horizonChanged = true;
- } else {
- horizonChanged = false;
- }
- h = newh;
+ h = accelGetHorizon (&horizonChanged);
switch (mode) {
case UIMODE_INIT:
@@ -514,12 +503,11 @@ void uiLoop () {
sleepwhile (wakeup == 0);
#if 0
- printf ("t=%i, h=%i, s=%i\n", gyroGetZTicks (), accelGetHorizon (),
+ printf ("t=%i, h=%i, s=%i\n", gyroGetZTicks (), h,
accelGetShakeCount ());
const int32_t gyroval = gyroGetZAccum ();
const int16_t gyroraw = gyroGetZRaw ();
- const int8_t accelval = accelGetZ ();
- printf ("%li - %i - %i\n", gyroval, gyroraw, accelval);
+ printf ("%li - %i\n", gyroval, gyroraw);
#endif
}