cleanup and code examples in README
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355
README.md
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README.md
@ -1,10 +1,10 @@
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# LIS3DH
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A C89 driver for the 3-axis accelerometer LIS3DH by ST. Supports both i2c and SPI.
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A C89 driver for the 3-axis accelerometer LIS3DH. Supports both i2c and SPI.
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> ### Features
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> - FIFO of varying watermark level, up to 32
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> - HP filter
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> - HP filter (4 c/o freq)
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> - 2G, 4G, 8G and 16G
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> - All power modes
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> - Interrupt generation (soon)
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@ -12,66 +12,314 @@ A C89 driver for the 3-axis accelerometer LIS3DH by ST. Supports both i2c and SP
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> - Single and double click detection (soon)
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> - 4D/6D orientation detection (soon)
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FIFO output example
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```
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$ ./lis3dh
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x: 0.5320, y: -0.8800, z: -0.0600 mag: 1.0301
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x: 0.5440, y: -0.8680, z: -0.0760 mag: 1.0272
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x: 0.5440, y: -0.8720, z: -0.0760 mag: 1.0306
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x: 0.5440, y: -0.8720, z: -0.0760 mag: 1.0306
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x: 0.5440, y: -0.8720, z: -0.0760 mag: 1.0306
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x: 0.5440, y: -0.8720, z: -0.0760 mag: 1.0306
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x: 0.5440, y: -0.8720, z: -0.0760 mag: 1.0306
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x: 0.5440, y: -0.8720, z: -0.0760 mag: 1.0306
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x: 0.5440, y: -0.8720, z: -0.0760 mag: 1.0306
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x: 0.5440, y: -0.8720, z: -0.0760 mag: 1.0306
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x: 0.5440, y: -0.8720, z: -0.0760 mag: 1.0306
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x: 0.5440, y: -0.8720, z: -0.0720 mag: 1.0303
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x: 0.5480, y: -0.8800, z: -0.0720 mag: 1.0392
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x: 0.5480, y: -0.8800, z: -0.0720 mag: 1.0392
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x: 0.5480, y: -0.8800, z: -0.0720 mag: 1.0392
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x: 0.5480, y: -0.8800, z: -0.0720 mag: 1.0392
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x: 0.5480, y: -0.8800, z: -0.0720 mag: 1.0392
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x: 0.5480, y: -0.8800, z: -0.0720 mag: 1.0392
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x: 0.5480, y: -0.8800, z: -0.0720 mag: 1.0392
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x: 0.5480, y: -0.8800, z: -0.0720 mag: 1.0392
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x: 0.5480, y: -0.8800, z: -0.0720 mag: 1.0392
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x: 0.5480, y: -0.8800, z: -0.0720 mag: 1.0392
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x: 0.5480, y: -0.8800, z: -0.0720 mag: 1.0392
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x: 0.5480, y: -0.8800, z: -0.0720 mag: 1.0392
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x: 0.5480, y: -0.8800, z: -0.0720 mag: 1.0392
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x: 0.5480, y: -0.8800, z: -0.0720 mag: 1.0392
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x: 0.5480, y: -0.8800, z: -0.0720 mag: 1.0392
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x: 0.5480, y: -0.8800, z: -0.0720 mag: 1.0392
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x: 0.5480, y: -0.8800, z: -0.0720 mag: 1.0392
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x: 0.5480, y: -0.8800, z: -0.0720 mag: 1.0392
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x: 0.5480, y: -0.8800, z: -0.0800 mag: 1.0398
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x: 0.5480, y: -0.8960, z: -0.0960 mag: 1.0547
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```
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> ### Notes
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> FIFO is always and only 10-bit
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### Noise at 2G
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## Usage
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Simple example:
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```c
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#define _GNU_SOURCE
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#include <unistd.h> /* usleep() */
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#include <stdio.h>
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#include "lis3dh.h"
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#include "i2c.h"
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### Noise at 4G
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int main() {
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### Noise at 8G
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lis3dh_t lis;
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### Noise at 16G
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lis.dev.init = i2c_init;
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lis.dev.read = i2c_read;
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lis.dev.write = i2c_write;
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lis.dev.sleep = usleep;
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lis.dev.deinit = i2c_deinit;
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if (lis3dh_init(&lis)) {
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/* error handling */
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}
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## Using i2c on STM32
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lis.cfg.mode = LIS3DH_MODE_HR;
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lis.cfg.range = LIS3DH_FS_4G;
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lis.cfg.rate = LIS3DH_ODR_100_HZ;
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if (lis3dh_configure(&lis)) {
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/* error handling */
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}
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if (lis3dh_poll(&lis)) {
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/* error handling */
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}
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if (lis3dh_read(&lis)) {
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/* error handling */
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}
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printf("x: %f, y: %f, z: %f\n", lis.acc.x, lis.acc.y, lis.acc.z);
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if (lis3dh_deinit(&lis)) {
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/* error handling */
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}
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return 0;
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}
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```
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The output should be something similar to this:
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```
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$ ./lis3dh
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x: 0.540000, y: -0.882000, z: -0.100000
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```
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poll() and read() can be indefinitely looped for a constant data stream, like this:
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```c
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#define _GNU_SOURCE
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#include <unistd.h>
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#include <stdio.h>
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#include "lis3dh.h"
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#include "i2c.h"
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int main() {
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lis3dh_t lis;
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int i;
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lis.dev.init = i2c_init;
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lis.dev.read = i2c_read;
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lis.dev.write = i2c_write;
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lis.dev.sleep = usleep;
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lis.dev.deinit = i2c_deinit;
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if (lis3dh_init(&lis)) {
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/* error handling */
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}
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lis.cfg.mode = LIS3DH_MODE_HR;
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lis.cfg.range = LIS3DH_FS_4G;
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lis.cfg.rate = LIS3DH_ODR_100_HZ;
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if (lis3dh_configure(&lis)) {
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/* error handling */
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}
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for(i=0; i<10; i++) {
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if (lis3dh_poll(&lis)) {
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/* error handling */
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}
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if (lis3dh_read(&lis)) {
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/* error handling */
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}
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printf("x: %f, y: %f, z: %f\n", lis.acc.x, lis.acc.y, lis.acc.z);
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}
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if (lis3dh_deinit(&lis)) {
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/* error handling */
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}
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return 0;
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}
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```
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Output:
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```
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$ ./lis3dh
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x: 0.534000, y: -0.882000, z: -0.102000
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x: 0.538000, y: -0.866000, z: -0.136000
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x: 0.518000, y: -0.846000, z: -0.100000
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x: 0.518000, y: -0.840000, z: -0.098000
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x: 0.542000, y: -0.876000, z: -0.098000
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x: 0.518000, y: -0.834000, z: -0.146000
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x: 0.512000, y: -0.854000, z: -0.106000
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x: 0.574000, y: -0.870000, z: -0.122000
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x: 0.518000, y: -0.846000, z: -0.098000
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x: 0.516000, y: -0.852000, z: -0.112000
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```
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## Using FIFO
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Instead of polling for every single [x y z] set, a FIFO with programmable capacity ("watermark") can be used like such:
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It should be noted that all FIFO readings use 10-bit resolution regardless of the mode. The watermark level can also be adjusted to a value [0-32] inclusive by modifying the `lis.cfg.fifo.fth` property before calling configure().
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```c
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#define _GNU_SOURCE
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#include <unistd.h>
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#include <stdio.h>
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#include "lis3dh.h"
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#include "i2c.h"
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int main() {
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lis3dh_t lis;
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struct lis3dh_fifo_data data;
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int i;
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lis.dev.init = i2c_init;
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lis.dev.read = i2c_read;
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lis.dev.write = i2c_write;
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lis.dev.sleep = usleep;
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lis.dev.deinit = i2c_deinit;
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if (lis3dh_init(&lis)) {
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/* error handling */
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}
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lis.cfg.mode = LIS3DH_MODE_HR;
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lis.cfg.range = LIS3DH_FS_4G;
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lis.cfg.rate = LIS3DH_ODR_100_HZ;
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lis.cfg.fifo.mode = LIS3DH_FIFO_MODE_NORMAL;
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if (lis3dh_configure(&lis)) {
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/* error handling */
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}
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if (lis3dh_poll_fifo(&lis)) {
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/* error handling */
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}
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if (lis3dh_read_fifo(&lis, &data)) {
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/* error handling */
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}
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/* read out fifo buffer data */
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for(i=0; i<data.size; i++) {
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printf("x: %f, y: %f, z: %f\n", data.x[i], data.y[i], data.z[i]);
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}
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if (lis3dh_deinit(&lis)) {
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/* error handling */
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}
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return 0;
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}
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```
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Output:
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```
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$ ./lis3dh
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x: 0.544000, y: -0.904000, z: -0.104000
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x: 0.536000, y: -0.880000, z: -0.104000
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x: 0.528000, y: -0.880000, z: -0.104000
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x: 0.528000, y: -0.880000, z: -0.104000
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x: 0.536000, y: -0.880000, z: -0.104000
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x: 0.536000, y: -0.880000, z: -0.104000
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x: 0.536000, y: -0.880000, z: -0.104000
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x: 0.536000, y: -0.880000, z: -0.104000
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x: 0.536000, y: -0.880000, z: -0.104000
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x: 0.536000, y: -0.880000, z: -0.104000
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x: 0.536000, y: -0.880000, z: -0.104000
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x: 0.536000, y: -0.880000, z: -0.128000
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x: 0.568000, y: -0.872000, z: -0.160000
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x: 0.568000, y: -0.872000, z: -0.160000
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x: 0.568000, y: -0.872000, z: -0.160000
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x: 0.568000, y: -0.872000, z: -0.160000
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x: 0.568000, y: -0.872000, z: -0.160000
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x: 0.568000, y: -0.872000, z: -0.160000
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x: 0.568000, y: -0.872000, z: -0.160000
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x: 0.568000, y: -0.872000, z: -0.160000
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x: 0.568000, y: -0.872000, z: -0.160000
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x: 0.568000, y: -0.872000, z: -0.160000
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x: 0.568000, y: -0.872000, z: -0.160000
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x: 0.568000, y: -0.872000, z: -0.160000
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x: 0.568000, y: -0.872000, z: -0.160000
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x: 0.568000, y: -0.872000, z: -0.160000
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x: 0.568000, y: -0.872000, z: -0.160000
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x: 0.568000, y: -0.872000, z: -0.160000
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x: 0.568000, y: -0.872000, z: -0.160000
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x: 0.568000, y: -0.872000, z: -0.160000
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x: 0.568000, y: -0.872000, z: -0.160000
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x: 0.560000, y: -0.872000, z: -0.160000
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```
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## Using the HP filter
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The LIS3DH can optionally apply a HP filter on the sample data. It can be used to greatly reduce the "DC acceleration" present.
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```c
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#define _GNU_SOURCE
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#include <unistd.h>
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#include <stdio.h>
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#include "lis3dh.h"
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#include "i2c.h"
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int main() {
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lis3dh_t lis;
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struct lis3dh_fifo_data data;
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int i;
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lis.dev.init = i2c_init;
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lis.dev.read = i2c_read;
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lis.dev.write = i2c_write;
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lis.dev.sleep = usleep;
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lis.dev.deinit = i2c_deinit;
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if (lis3dh_init(&lis)) {
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/* error handling */
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}
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lis.cfg.mode = LIS3DH_MODE_HR;
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lis.cfg.range = LIS3DH_FS_4G;
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lis.cfg.rate = LIS3DH_ODR_100_HZ;
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lis.cfg.fifo.mode = LIS3DH_FIFO_MODE_NORMAL;
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lis.cfg.filter.mode = LIS3DH_FILTER_MODE_AUTORESET;
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lis.cfg.filter.cutoff = LIS3DH_FILTER_CUTOFF_8;
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if (lis3dh_configure(&lis)) {
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/* error handling */
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}
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if (lis3dh_poll_fifo(&lis)) {
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/* error handling */
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}
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if (lis3dh_read_fifo(&lis, &data)) {
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/* error handling */
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}
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/* read out fifo buffer data */
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for(i=0; i<data.size; i++) {
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printf("x: %f, y: %f, z: %f\n", data.x[i], data.y[i], data.z[i]);
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}
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if (lis3dh_deinit(&lis)) {
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/* error handling */
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}
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return 0;
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}
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```
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Output:
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```
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$ ./lis3dh
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x: 0.008000, y: 0.000000, z: 0.000000
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x: 0.000000, y: 0.000000, z: 0.016000
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x: -0.016000, y: -0.008000, z: -0.008000
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x: -0.032000, y: 0.008000, z: 0.000000
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x: 0.024000, y: -0.016000, z: -0.032000
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x: 0.024000, y: -0.016000, z: -0.032000
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x: 0.024000, y: -0.016000, z: -0.032000
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x: 0.024000, y: -0.016000, z: -0.032000
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x: 0.024000, y: -0.016000, z: -0.032000
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x: 0.024000, y: -0.016000, z: -0.032000
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x: 0.024000, y: -0.016000, z: -0.032000
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x: 0.024000, y: -0.016000, z: -0.008000
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x: -0.016000, y: -0.032000, z: -0.040000
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x: -0.016000, y: -0.032000, z: -0.040000
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x: -0.016000, y: -0.032000, z: -0.040000
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x: -0.016000, y: -0.032000, z: -0.040000
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x: -0.016000, y: -0.032000, z: -0.040000
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x: -0.016000, y: -0.032000, z: -0.040000
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x: -0.016000, y: -0.032000, z: -0.040000
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x: -0.016000, y: -0.032000, z: -0.040000
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x: -0.016000, y: -0.032000, z: -0.040000
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x: -0.016000, y: -0.032000, z: -0.040000
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x: -0.016000, y: -0.032000, z: -0.040000
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x: -0.016000, y: -0.032000, z: -0.040000
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x: -0.016000, y: -0.032000, z: -0.040000
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x: -0.016000, y: -0.032000, z: -0.040000
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x: -0.016000, y: -0.032000, z: -0.040000
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x: -0.016000, y: -0.032000, z: -0.040000
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x: -0.016000, y: -0.032000, z: -0.040000
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x: -0.016000, y: -0.032000, z: -0.040000
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x: -0.016000, y: -0.032000, z: -0.040000
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x: -0.008000, y: -0.024000, z: -0.008000
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```
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||||
### Using i2c on STM32
|
||||
Simple example code
|
||||
```c
|
||||
#define LIS3DH_I2C_ADDR 0x18
|
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@ -89,3 +337,4 @@ int i2c_read(uint8_t reg, uint8_t *dst, uint32_t size) {
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return 0;
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||||
}
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||||
```
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6
main.c
6
main.c
@ -38,7 +38,7 @@ int main() {
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||||
}
|
||||
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||||
/* set up config */
|
||||
lis.cfg.mode = LIS3DH_MODE_HR;
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lis.cfg.mode = LIS3DH_MODE_NORMAL;
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lis.cfg.range = LIS3DH_FS_2G;
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lis.cfg.rate = LIS3DH_ODR_100_HZ;
|
||||
lis.cfg.fifo.mode = LIS3DH_FIFO_MODE_STREAM;
|
||||
@ -48,7 +48,7 @@ int main() {
|
||||
quit("configure()", &lis);
|
||||
}
|
||||
|
||||
for (i=0; i<50; i++) {
|
||||
for (i=0; i<100; i++) {
|
||||
|
||||
/* poll fifo reg */
|
||||
if (lis3dh_poll_fifo(&lis)) {
|
||||
@ -61,7 +61,7 @@ int main() {
|
||||
}
|
||||
|
||||
for(k=0; k<fifo.size; k++) {
|
||||
printf("x: %04.04f, y: %04.04f, z: %04.04f mag: %04.04f\n",
|
||||
printf("%04.04f %04.04f %04.04f %04.04f\n",
|
||||
fifo.x[k], fifo.y[k], fifo.z[k],
|
||||
mag(fifo.x[k], fifo.y[k], fifo.z[k]));
|
||||
}
|
||||
|
||||
41
plot.gp
41
plot.gp
@ -1,41 +0,0 @@
|
||||
# gnuplot
|
||||
reset
|
||||
|
||||
set terminal pngcairo enhanced size 1920/2,1080/2
|
||||
set grid
|
||||
set key box opaque
|
||||
|
||||
set ylabel "|[x y z]| - 1g"
|
||||
set xlabel "Samples over time"
|
||||
set yrange [-0.3:0.1]
|
||||
|
||||
n(g) = g - 1.0
|
||||
|
||||
do for [g in "2g 4g 8g 16g"] {
|
||||
name = sprintf("graph-%s", g)
|
||||
out = sprintf("%s.png", name)
|
||||
stub = sprintf("data/fifo_%s_", g)
|
||||
set title sprintf("[%s FIFO] comparison of ODR setting effect on magnitude of [x y z] acc vector (- 1g)", g)
|
||||
set output out
|
||||
plot stub."50.txt" u n(4) w p ps 0.3 t "50 Hz", \
|
||||
stub."100.txt" u n(4) w p ps 0.3 t "100 Hz", \
|
||||
stub."200.txt" u n(4) w p ps 0.3 t "200 Hz", \
|
||||
stub."400.txt" u n(4) w p ps 0.3 t "400 Hz", \
|
||||
}
|
||||
|
||||
set ylabel "|[x y z]|"
|
||||
set xlabel "Samples over time"
|
||||
set yrange [-0.1:0.1]
|
||||
|
||||
|
||||
do for [g in "2g 4g 8g 16g"] {
|
||||
name = sprintf("graph-%s-filter", g)
|
||||
out = sprintf("%s.png", name)
|
||||
stub = sprintf("data/filt_%s_", g)
|
||||
set title sprintf("[%s AUTORESET filter] comparison of f_{cutoff} DC acc. removal", g)
|
||||
set output out
|
||||
plot stub."1.txt" u n(4) w p ps 0.3 t "1", \
|
||||
stub."2.txt" u n(4) w p ps 0.3 t "2", \
|
||||
stub."4.txt" u n(4) w p ps 0.3 t "4", \
|
||||
stub."8.txt" u n(4) w p ps 0.3 t "8", \
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user