#if HAS_MMC5983
+#define DEBUG_MMC5983 0
+
struct ao_mmc5983_sample ao_mmc5983_current;
+static struct ao_mmc5983_sample ao_mmc5983_offset;
static uint8_t ao_mmc5983_configured;
}
static void
-ao_mmc5983_sample(struct ao_mmc5983_sample *sample)
+ao_mmc5983_raw(struct ao_mmc5983_raw *raw)
{
- struct ao_mmc5983_raw raw;
-
ao_i2c_bit_start(MMC5983_I2C_ADDR);
- raw.addr = MMC5983_X_OUT_0;
- ao_i2c_bit_send(&raw.addr, 1);
+ raw->addr = MMC5983_X_OUT_0;
+ ao_i2c_bit_send(&(raw->addr), 1);
ao_i2c_bit_restart(MMC5983_I2C_ADDR | 1);
- ao_i2c_bit_recv(&raw.x0, 7);
+ ao_i2c_bit_recv(&(raw->x0), sizeof(*raw) - 1);
ao_i2c_bit_stop();
-
- sample->x = raw.x0 << 10 | raw.x1 << 2 | ((raw.xyz2 >> 6) & 3);
- sample->y = raw.y0 << 10 | raw.y1 << 2 | ((raw.xyz2 >> 4) & 3);
- sample->z = raw.z0 << 10 | raw.z1 << 2 | ((raw.xyz2 >> 2) & 3);
}
#else
}
static void
-ao_mmc5983_sample(struct ao_mmc5983_sample *sample)
+ao_mmc5983_raw(struct ao_mmc5983_raw *raw)
{
- struct ao_mmc5983_raw raw;
+ raw->addr = MMC5983_X_OUT_0 | MMC5983_READ;
+ ao_mmc5983_duplex((uint8_t *) raw, sizeof (*raw));
+}
+#endif
- raw.addr = MMC5983_X_OUT_0 | MMC5983_READ;
- ao_mmc5983_duplex((uint8_t *) &raw, sizeof (raw));
+/* Saturating subtraction. Keep the result within range
+ * of an int16_t
+ */
+static int16_t
+sat_sub(int16_t a, int16_t b)
+{
+ int32_t v = (int32_t) a - (int32_t) b;
+ if (v < -32768)
+ v = -32768;
+ if (v > 32767)
+ v = 32767;
+ return v;
+}
- sample->x = raw.x0 << 10 | raw.x1 << 2 | ((raw.xyz2 >> 6) & 3);
- sample->y = raw.y0 << 10 | raw.y1 << 2 | ((raw.xyz2 >> 4) & 3);
- sample->z = raw.z0 << 10 | raw.z1 << 2 | ((raw.xyz2 >> 2) & 3);
+/* Wait for a synchronous sample to finish */
+static void
+ao_mmc5983_wait(void)
+{
+ for (;;) {
+ uint8_t status = ao_mmc5983_reg_read(MMC5983_STATUS);
+ if ((status & (1 << MMC5983_STATUS_MEAS_M_DONE)) != 0)
+ break;
+ ao_delay(0);
+ }
}
-#endif
-static uint8_t product_id;
+static void
+ao_mmc5983_set(void)
+{
+ ao_mmc5983_reg_write(MMC5983_CONTROL_0,
+ (1 << MMC5983_CONTROL_0_SET));
+}
-static uint8_t
-ao_mmc5983_setup(void)
+static void
+ao_mmc5983_reset(void)
{
+ ao_mmc5983_reg_write(MMC5983_CONTROL_0,
+ (1 << MMC5983_CONTROL_0_RESET));
+}
- if (ao_mmc5983_configured)
- return 1;
+static struct ao_mmc5983_raw raw;
- /* Delay for power up time (10ms) */
- ao_delay(AO_MS_TO_TICKS(10));
+/* Read the sensor values and convert to a sample struct */
+static void
+ao_mmc5983_sample(struct ao_mmc5983_sample *s)
+{
+ ao_mmc5983_raw(&raw);
+
+ /* Bias by 32768 to convert from uint16_t to int16_t */
+ s->x = (int32_t) (((uint16_t) raw.x0 << 8) | raw.x1) - 32768;
+ s->y = (int32_t) (((uint16_t) raw.y0 << 8) | raw.y1) - 32768;
+ s->z = (int32_t) (((uint16_t) raw.z0 << 8) | raw.z1) - 32768;;
+}
+
+/* Synchronously sample the sensors */
+static void
+ao_mmc5983_sync_sample(struct ao_mmc5983_sample *v)
+{
+ ao_mmc5983_reg_write(MMC5983_CONTROL_0,
+ (1 << MMC5983_CONTROL_0_TM_M));
+ ao_mmc5983_wait();
+ ao_mmc5983_sample(v);
+}
+
+static struct ao_mmc5983_sample set, reset;
+
+/* Calibrate the device by finding the zero point */
+static void
+ao_mmc5983_cal(void)
+{
+ /* Compute offset */
+
+ ao_delay(AO_MS_TO_TICKS(100));
+
+ /* Measure in 'SET' mode */
+ ao_mmc5983_set();
+ ao_delay(AO_MS_TO_TICKS(100));
+ ao_mmc5983_sync_sample(&set);
+
+ ao_delay(AO_MS_TO_TICKS(100));
+
+ /* Measure in 'RESET' mode */
+ ao_mmc5983_reset();
+ ao_delay(AO_MS_TO_TICKS(100));
+ ao_mmc5983_sync_sample(&reset);
+
+ /* The zero point is the average of SET and RESET values */
+ ao_mmc5983_offset.x = ((int32_t) set.x + (int32_t) reset.x) / 2;
+ ao_mmc5983_offset.y = ((int32_t) set.y + (int32_t) reset.y) / 2;
+ ao_mmc5983_offset.z = ((int32_t) set.z + (int32_t) reset.z) / 2;
+}
+
+/* Configure the device to automatically sample at 200Hz */
+static void
+ao_mmc5983_run(void)
+{
+ /* Set bandwidth to 200Hz */
+ ao_mmc5983_reg_write(MMC5983_CONTROL_1,
+ MMC5983_CONTROL_1_BW_200 << MMC5983_CONTROL_1_BW);
+
+ /* Measure at 200Hz so we get recent samples by just reading
+ * the registers
+ */
+ ao_mmc5983_reg_write(MMC5983_CONTROL_2,
+ (1 << MMC5983_CONTROL_2_CMM_EN) |
+ (MMC5983_CONTROL_2_CM_FREQ_200HZ << MMC5983_CONTROL_2_CM_FREQ) |
+ (0 << MMC5983_CONTROL_2_EN_PRD_SET) |
+ (MMC5983_CONTROL_2_PRD_SET_1000));
+ ao_mmc5983_configured = 1;
+}
+
+/* Reboot the device by setting the SW_RST bit and waiting 10ms */
+static void
+ao_mmc5983_reboot(void)
+{
+ ao_mmc5983_configured = 0;
ao_mmc5983_reg_write(MMC5983_CONTROL_1,
1 << MMC5983_CONTROL_1_SW_RST);
/* Delay for power up time (10ms) */
ao_delay(AO_MS_TO_TICKS(10));
+}
+
+/* Configure the device for operation */
+static uint8_t
+ao_mmc5983_setup(void)
+{
+ uint8_t product_id;
+
+ /* Reboot the device */
+ ao_mmc5983_reboot();
/* Check product ID */
product_id = ao_mmc5983_reg_read(MMC5983_PRODUCT_ID);
AO_SENSOR_ERROR(AO_DATA_MMC5983);
}
- /* Set bandwidth to 200Hz */
- ao_mmc5983_reg_write(MMC5983_CONTROL_1,
- MMC5983_CONTROL_1_BW_200 << MMC5983_CONTROL_1_BW);
+ /* Calibrate */
+ ao_mmc5983_cal();
- /* Measure at 200Hz so we get recent samples by just reading
- * the registers
- */
- ao_mmc5983_reg_write(MMC5983_CONTROL_2,
- (1 << MMC5983_CONTROL_2_CMM_EN) |
- (MMC5983_CONTROL_2_CM_FREQ_200HZ << MMC5983_CONTROL_2_CM_FREQ));
+ /* Start automatic sampling */
+ ao_mmc5983_run();
- ao_mmc5983_configured = 1;
return 1;
}
struct ao_mmc5983_sample sample;
ao_mmc5983_setup();
for (;;) {
- ao_mmc5983_sample(&sample);
+ if (ao_mmc5983_configured)
+ ao_mmc5983_sample(&sample);
+ sample.x = sat_sub(sample.x, ao_mmc5983_offset.x);
+ sample.y = sat_sub(sample.y, ao_mmc5983_offset.y);
+ sample.z = sat_sub(sample.z, ao_mmc5983_offset.z);
ao_arch_block_interrupts();
ao_mmc5983_current = sample;
AO_DATA_PRESENT(AO_DATA_MMC5983);
static void
ao_mmc5983_show(void)
{
+#if DEBUG_MMC5983
+ printf ("x0 %02x x1 %02x y0 %02x y1 %02x z0 %02x z1 %02x\n",
+ raw.x0, raw.x1, raw.y0, raw.y1, raw.z0, raw.z1);
+
+ printf ("set.x %d set.y %d set.z %d\n",
+ set.x, set.y, set.z);
+
+ printf ("reset.x %d reset.y %d reset.z %d\n",
+ reset.x, reset.y, reset.z);
+
+ printf ("offset.x %d offset.y %d offset.z %d\n",
+ ao_mmc5983_offset.x,
+ ao_mmc5983_offset.y,
+ ao_mmc5983_offset.z);
+#endif
printf ("MMC5983: %d %d %d\n",
ao_mmc5983_along(&ao_mmc5983_current),
ao_mmc5983_across(&ao_mmc5983_current),
ao_mmc5983_through(&ao_mmc5983_current));
}
+#if DEBUG_MMC5983
+static void
+ao_mmc5983_recal(void)
+{
+ printf("recal\n"); fflush(stdout);
+ ao_mmc5983_reboot();
+ printf("reboot\n"); fflush(stdout);
+ ao_mmc5983_cal();
+ printf("cal\n"); fflush(stdout);
+ ao_mmc5983_show();
+ printf("show\n"); fflush(stdout);
+ ao_mmc5983_run();
+ printf("run\n"); fflush(stdout);
+}
+#endif
+
static const struct ao_cmds ao_mmc5983_cmds[] = {
{ ao_mmc5983_show, "M\0Show MMC5983 status" },
+#if DEBUG_MMC5983
+ { ao_mmc5983_recal, "m\0Recalibrate MMC5983" },
+#endif
{ 0, NULL }
};
projects / fw / altos / blobdiff