gyroscope: Rename to gyro

1 files changed, 77 insertions, 0 deletions

diff --git a/gyro.c b/gyro.c
new file mode 100644
index 0000000..f4d7529
--- /dev/null
+++ b/gyro.c
@@ -0,0 +1,77 @@
+#include <stdio.h>
+#include <avr/io.h>
+#include <avr/interrupt.h>
+#include <avr/sleep.h>
+
+#include "i2c.h"
+#include "gyro.h"
+
+/* device address */
+#define L3GD20 0b11010100
+/* registers */
+#define L3GD20_WHOAMI 0xf
+#define L3GD20_CTRLREG1 0x20
+#define L3GD20_CTRLREG3 0x22
+#define L3GD20_CTRLREG4 0x23
+
+#define sleepwhile(cond) \
+	sleep_enable (); \
+	while (cond) { sleep_cpu (); } \
+	sleep_disable ();
+
+/* the first interrupt is lost */
+volatile bool drdy = true;
+volatile int16_t val[3] = {0, 0, 0};
+
+/* data ready interrupt
+ */
+ISR(PCINT0_vect) {
+	drdy = true;
+}
+
+void gyroInit () {
+	/* set PB1 to input, with pull-up */
+	DDRB = (DDRB & ~((1 << PB1)));
+	PORTB = (PORTB | (1 << PB1));
+	/* enable interrupt PCI0 */
+	PCICR = (1 << PCIE0);
+	/* enable interrupts on PB1/PCINT1 */
+	PCMSK0 = (1 << 1);
+}
+
+/* XXX: make nonblocking */
+void gyroStart () {
+	/* configuration:
+	 * disable power-down-mode
+	 * defaults
+	 * enable drdy interrupt
+	 * select 500dps
+	 */
+	uint8_t data[] = {0b00001111, 0b0, 0b00001000, 0b00010000};
+
+	if (!twRequest (TWM_WRITE, L3GD20, L3GD20_CTRLREG1, data,
+			sizeof (data)/sizeof (*data))) {
+		printf ("cannot start write\n");
+	}
+	sleepwhile (twr.status == TWST_WAIT);
+	printf ("final twi status was %i\n", twr.status);
+}
+
+bool gyroRead () {
+	if (drdy) {
+		drdy = false;
+
+		if (!twRequest (TWM_READ, L3GD20, 0x28, (uint8_t *) val, 6)) {
+			printf ("cannot start read\n");
+		}
+
+		return true;
+	} else {
+		return false;
+	}
+}
+
+volatile const int16_t *gyroGet () {
+	return val;
+}
+