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/*
* Copyright © 2018 Keith Packard <keithp@keithp.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
#include <ao.h>
#include "ao_adxl375.h"
#define DEBUG_LOW 1
#define DEBUG_HIGH 2
#define DEBUG 0
#if DEBUG
#define PRINTD(l, ...) do { if (DEBUG & (l)) { printf ("\r%5u %s: ", ao_tick_count, __func__); printf(__VA_ARGS__); flush(); } } while(0)
#else
#define PRINTD(l,...)
#endif
struct ao_adxl375_sample ao_adxl375_current;
static void
ao_adxl375_start(void) {
ao_spi_get_bit(AO_ADXL375_CS_PORT,
AO_ADXL375_CS_PIN,
AO_ADXL375_SPI_INDEX,
AO_ADXL375_SPI_SPEED);
}
static void
ao_adxl375_stop(void) {
ao_spi_put_bit(AO_ADXL375_CS_PORT,
AO_ADXL375_CS_PIN,
AO_ADXL375_SPI_INDEX);
}
static uint8_t
ao_adxl375_reg_read(uint8_t addr)
{
uint8_t d[2];
d[0] = addr | AO_ADXL375_READ;
ao_adxl375_start();
ao_spi_duplex(d, d, 2, AO_ADXL375_SPI_INDEX);
ao_adxl375_stop();
PRINTD(DEBUG_LOW, "read %x = %x\n", addr, d);
return d[1];
}
static void
ao_adxl375_reg_write(uint8_t addr, uint8_t value)
{
uint8_t d[2];
PRINTD(DEBUG_LOW, "write %x %x\n", addr, value);
d[0] = addr;
d[1] = value;
ao_adxl375_start();
ao_spi_send(d, 2, AO_ADXL375_SPI_INDEX);
ao_adxl375_stop();
#if DEBUG & DEBUG_LOW
d[0] = addr | AO_ADXL375_READ
d[1] = 0;
ao_adxl375_start();
ao_spi_duplex(d, d, 2, AO_ADXL375_SPI_INDEX);
ao_adxl375_stop();
PRINTD(DEBUG_LOW, "readback %x %x\n", d[0], d[1]);
#endif
}
static void
ao_adxl375_value(struct ao_adxl375_sample *value)
{
uint8_t d[7];
d[0] = AO_ADXL375_DATAX0 | AO_ADXL375_READ | AO_ADXL375_MULTI_BYTE;
ao_adxl375_start();
ao_spi_duplex(d, d, 7, AO_ADXL375_SPI_INDEX);
ao_adxl375_stop();
memcpy(value, &d[1], 6);
}
struct ao_adxl375_total {
int32_t x;
int32_t y;
int32_t z;
};
#define AO_ADXL375_SELF_TEST_SAMPLES 10
#define AO_ADXL375_SELF_TEST_SETTLE 4
#define MIN_LSB_G 18.4
#define MAX_LSB_G 22.6
#define SELF_TEST_MIN_G 6.0
#define SELF_TEST_MAX_G 6.8
#define MIN_SELF_TEST ((int32_t) (MIN_LSB_G * SELF_TEST_MIN_G * AO_ADXL375_SELF_TEST_SAMPLES + 0.5))
#define MAX_SELF_TEST ((int32_t) (MAX_LSB_G * SELF_TEST_MAX_G * AO_ADXL375_SELF_TEST_SAMPLES + 0.5))
static void
ao_adxl375_total_value(struct ao_adxl375_total *total, int samples)
{
struct ao_adxl375_sample value;
*total = (struct ao_adxl375_total) { 0, 0, 0 };
for (int i = 0; i < samples; i++) {
ao_adxl375_value(&value);
total->x += value.x;
total->y += value.y;
total->z += value.z;
ao_delay(AO_MS_TO_TICKS(10));
}
}
#define AO_ADXL375_DATA_FORMAT_SETTINGS(self_test) ( \
AO_ADXL375_DATA_FORMAT_FIXED | \
(self_test << AO_ADXL375_DATA_FORMAT_SELF_TEST) | \
(AO_ADXL375_DATA_FORMAT_SPI_4_WIRE << AO_ADXL375_DATA_FORMAT_SPI_4_WIRE) | \
(0 << AO_ADXL375_DATA_FORMAT_INT_INVERT) | \
(0 << AO_ADXL375_DATA_FORMAT_JUSTIFY))
static int32_t self_test_value;
static void
ao_adxl375_setup(void)
{
/* Get the device into 4-wire SPI mode before proceeding */
ao_adxl375_reg_write(AO_ADXL375_DATA_FORMAT,
AO_ADXL375_DATA_FORMAT_SETTINGS(0));
uint8_t devid = ao_adxl375_reg_read(AO_ADXL375_DEVID);
if (devid != AO_ADXL375_DEVID_ID)
AO_SENSOR_ERROR(AO_DATA_ADXL375);
/* Set the data rate */
ao_adxl375_reg_write(AO_ADXL375_BW_RATE,
(0 << AO_ADXL375_BW_RATE_LOW_POWER) |
(AO_ADXL375_BW_RATE_RATE_200 << AO_ADXL375_BW_RATE_RATE));
/* Set the offsets all to zero */
ao_adxl375_reg_write(AO_ADXL375_OFSX, 0);
ao_adxl375_reg_write(AO_ADXL375_OFSY, 0);
ao_adxl375_reg_write(AO_ADXL375_OFSZ, 0);
/* Clear interrupts */
ao_adxl375_reg_write(AO_ADXL375_INT_ENABLE, 0);
/* Configure FIFO (disable) */
ao_adxl375_reg_write(AO_ADXL375_FIFO_CTL,
(AO_ADXL375_FIFO_CTL_FIFO_MODE_BYPASS << AO_ADXL375_FIFO_CTL_FIFO_MODE) |
(0 << AO_ADXL375_FIFO_CTL_TRIGGER) |
(0 << AO_ADXL375_FIFO_CTL_SAMPLES));
/* Place part in measurement mode */
ao_adxl375_reg_write(AO_ADXL375_POWER_CTL,
(0 << AO_ADXL375_POWER_CTL_LINK) |
(0 << AO_ADXL375_POWER_CTL_AUTO_SLEEP) |
(1 << AO_ADXL375_POWER_CTL_MEASURE) |
(0 << AO_ADXL375_POWER_CTL_SLEEP) |
(AO_ADXL375_POWER_CTL_WAKEUP_8 << AO_ADXL375_POWER_CTL_WAKEUP));
/* Perform self-test */
struct ao_adxl375_total self_test_off, self_test_on;
/* Discard some samples to let it settle down */
ao_adxl375_total_value(&self_test_off, AO_ADXL375_SELF_TEST_SETTLE);
/* Get regular values */
ao_adxl375_total_value(&self_test_off, AO_ADXL375_SELF_TEST_SAMPLES);
/* Turn on self test */
ao_adxl375_reg_write(AO_ADXL375_DATA_FORMAT,
AO_ADXL375_DATA_FORMAT_SETTINGS(1));
/* Discard at least 4 samples to let the device settle */
ao_adxl375_total_value(&self_test_on, AO_ADXL375_SELF_TEST_SETTLE);
/* Read self test samples */
ao_adxl375_total_value(&self_test_on, AO_ADXL375_SELF_TEST_SAMPLES);
/* Reset back to normal mode */
ao_adxl375_reg_write(AO_ADXL375_DATA_FORMAT,
AO_ADXL375_DATA_FORMAT_SETTINGS(0));
/* Verify Z axis value is in range */
int32_t z_change = self_test_on.z - self_test_off.z;
self_test_value = z_change;
if (z_change < MIN_SELF_TEST)
AO_SENSOR_ERROR(AO_DATA_ADXL375);
/* This check is commented out as maximum self test is unreliable
if (z_change > MAX_SELF_TEST)
AO_SENSOR_ERROR(AO_DATA_ADXL375);
*/
/* Discard some samples to let it settle down */
ao_adxl375_total_value(&self_test_off, AO_ADXL375_SELF_TEST_SETTLE);
}
static void
ao_adxl375(void)
{
ao_adxl375_setup();
for (;;) {
ao_adxl375_value(&ao_adxl375_current);
ao_arch_critical(
AO_DATA_PRESENT(AO_DATA_ADXL375);
AO_DATA_WAIT();
);
}
}
static struct ao_task ao_adxl375_task;
static void
ao_adxl375_dump(void)
{
printf ("ADXL375 value %d %d %d self test %d min %d max %d\n",
ao_adxl375_current.x,
ao_adxl375_current.y,
ao_adxl375_current.z,
self_test_value,
MIN_SELF_TEST,
MAX_SELF_TEST);
}
const struct ao_cmds ao_adxl375_cmds[] = {
{ ao_adxl375_dump, "A\0Display ADXL375 data" },
{ 0, NULL },
};
void
ao_adxl375_init(void)
{
ao_cmd_register(ao_adxl375_cmds);
ao_spi_init_cs(AO_ADXL375_CS_PORT, (1 << AO_ADXL375_CS_PIN));
ao_add_task(&ao_adxl375_task, ao_adxl375, "adxl375");
}
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