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servo_dec.c
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servo_dec.c
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/*
Copyright 2016 Benjamin Vedder [email protected]
This file is part of the VESC firmware.
The VESC firmware 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 3 of the License, or
(at your option) any later version.
The VESC firmware 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.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "servo_dec.h"
#include "stm32f4xx_conf.h"
#include "ch.h"
#include "hal.h"
#include "hw.h"
#include "utils.h"
/*
* Settings
*/
#define SERVO_NUM 1
#define TIMER_FREQ 1000000
// Private variables
static volatile systime_t last_update_time;
static volatile float servo_pos[SERVO_NUM];
static volatile float pulse_start = 1.0;
static volatile float pulse_end = 2.0;
static volatile float last_len_received[SERVO_NUM];
static volatile bool use_median_filter = false;
static volatile bool is_running = false;
// Function pointers
static void(*done_func)(void) = 0;
static void icuwidthcb(ICUDriver *icup) {
last_len_received[0] = ((float)icuGetWidthX(icup) / ((float)TIMER_FREQ / 1000.0));
float len = last_len_received[0] - pulse_start;
const float len_set = (pulse_end - pulse_start);
if (len > len_set) {
if (len < (len_set * 1.2)) {
len = len_set;
} else {
// Too long pulse. Most likely something is wrong.
len = -1.0;
}
} else if (len < 0.0) {
if ((len + pulse_start) > (pulse_start * 0.8)) {
len = 0.0;
} else {
// Too short pulse. Most likely something is wrong.
len = -1.0;
}
}
if (len >= 0.0) {
if (use_median_filter) {
float c = (len * 2.0 - len_set) / len_set;
static float c1 = 0.5;
static float c2 = 0.5;
float med = utils_middle_of_3(c, c1, c2);
c2 = c1;
c1 = c;
servo_pos[0] = med;
} else {
servo_pos[0] = (len * 2.0 - len_set) / len_set;
}
last_update_time = chVTGetSystemTime();
if (done_func) {
done_func();
}
}
}
static void icuperiodcb(ICUDriver *icup) {
(void)icup;
}
static ICUConfig icucfg = {
ICU_INPUT_ACTIVE_HIGH,
TIMER_FREQ,
icuwidthcb,
icuperiodcb,
NULL,
HW_ICU_CHANNEL,
0
};
/**
* Initialize the serve decoding driver.
*
* @param d_func
* A function that should be called every time the servo signals have been
* decoded. Can be NULL.
*/
void servodec_init(void (*d_func)(void)) {
icuStart(&HW_ICU_DEV, &icucfg);
palSetPadMode(HW_ICU_GPIO, HW_ICU_PIN, PAL_MODE_ALTERNATE(HW_ICU_GPIO_AF));
icuStartCapture(&HW_ICU_DEV);
icuEnableNotifications(&HW_ICU_DEV);
for (int i = 0;i < SERVO_NUM;i++) {
servo_pos[i] = 0.0;
last_len_received[i] = 0.0;
}
// Set our function pointer
done_func = d_func;
is_running = true;
}
/**
* Stop the servo decoding driver
*/
void servodec_stop(void) {
if (is_running) {
icuStop(&HW_ICU_DEV);
palSetPadMode(HW_ICU_GPIO, HW_ICU_PIN, PAL_MODE_INPUT);
pulse_start = 1.0;
pulse_end = 2.0;
use_median_filter = false;
done_func = 0;
}
is_running = false;
}
/**
* Change the limits of how the servo pulses should be decoded.
*
* @param start
* The amount of milliseconds the pulse starts at (default is 1.0)
*
* @param end
* he amount of milliseconds the pulse ends at (default is 2.0)
*/
void servodec_set_pulse_options(float start, float end, bool median_filter) {
pulse_start = start;
pulse_end = end;
use_median_filter = median_filter;
}
/**
* Get a decoded servo value.
*
* @param servo_num
* The servo index. If it is out of range, 0.0 will be returned.
*
* @return
* The servo value in the range [-1.0 1.0].
*/
float servodec_get_servo(int servo_num) {
if (servo_num < SERVO_NUM) {
return servo_pos[servo_num];
} else {
return 0.0;
}
}
/**
* Get the amount of milliseconds that has passed since
* the last time servo positions were received.
*
* @return
* The amount of milliseconds that have passed since an update.
*/
uint32_t servodec_get_time_since_update(void) {
return chVTTimeElapsedSinceX(last_update_time) / (CH_CFG_ST_FREQUENCY / 1000);
}
/**
* Get the length of the last received pulse.
*
* @param servo_num
* The servo index. If it is out of range, 0.0 will be returned.
*
* @return
* The length of the last received pulse.
*/
float servodec_get_last_pulse_len(int servo_num) {
if (servo_num < SERVO_NUM) {
return last_len_received[servo_num];
} else {
return 0.0;
}
}