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ardupilot/libraries/AP_RSSI/AP_RSSI.cpp

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/*
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 3 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.
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 <AP_RSSI/AP_RSSI.h>
#include <GCS_MAVLink/GCS.h>
#include <RC_Channel/RC_Channel.h>
#include <utility>
extern const AP_HAL::HAL& hal;
#ifdef CONFIG_ARCH_BOARD_PX4FMU_V4
#define BOARD_RSSI_DEFAULT 1
#define BOARD_RSSI_ANA_PIN 11
#define BOARD_RSSI_ANA_PIN_HIGH 3.3f
#endif
#ifndef BOARD_RSSI_DEFAULT
#define BOARD_RSSI_DEFAULT 0
#endif
#ifndef BOARD_RSSI_ANA_PIN
#define BOARD_RSSI_ANA_PIN 0
#endif
#ifndef BOARD_RSSI_ANA_PIN_HIGH
#define BOARD_RSSI_ANA_PIN_HIGH 5.0f
#endif
const AP_Param::GroupInfo AP_RSSI::var_info[] = {
// @Param: TYPE
// @DisplayName: RSSI Type
// @Description: Radio Receiver RSSI type. If your radio receiver supports RSSI of some kind, set it here, then set its associated RSSI_XXXXX parameters, if any.
// @Values: 0:Disabled,1:AnalogPin,2:RCChannelPwmValue,3:ReceiverProtocol,4:PWMInputPin
// @User: Standard
AP_GROUPINFO_FLAGS("TYPE", 0, AP_RSSI, rssi_type, BOARD_RSSI_DEFAULT, AP_PARAM_FLAG_ENABLE),
// @Param: ANA_PIN
// @DisplayName: Receiver RSSI sensing pin
// @Description: Pin used to read the RSSI voltage or PWM value
// @Values: 11:Pixracer,13:Pixhawk ADC4,14:Pixhawk ADC3,15:Pixhawk ADC6,15:Pixhawk2 ADC,50:PixhawkAUX1,51:PixhawkAUX2,52:PixhawkAUX3,53:PixhawkAUX4,54:PixhawkAUX5,55:PixhawkAUX6,103:Pixhawk SBUS
// @User: Standard
AP_GROUPINFO("ANA_PIN", 1, AP_RSSI, rssi_analog_pin, BOARD_RSSI_ANA_PIN),
// @Param: PIN_LOW
// @DisplayName: RSSI pin's lowest voltage
// @Description: RSSI pin's voltage received on the RSSI_ANA_PIN when the signal strength is the weakest. Some radio receivers put out inverted values so this value may be higher than RSSI_PIN_HIGH
// @Units: V
// @Increment: 0.01
// @Range: 0 5.0
// @User: Standard
AP_GROUPINFO("PIN_LOW", 2, AP_RSSI, rssi_analog_pin_range_low, 0.0f),
// @Param: PIN_HIGH
// @DisplayName: RSSI pin's highest voltage
// @Description: RSSI pin's voltage received on the RSSI_ANA_PIN when the signal strength is the strongest. Some radio receivers put out inverted values so this value may be lower than RSSI_PIN_LOW
// @Units: V
// @Increment: 0.01
// @Range: 0 5.0
// @User: Standard
AP_GROUPINFO("PIN_HIGH", 3, AP_RSSI, rssi_analog_pin_range_high, BOARD_RSSI_ANA_PIN_HIGH),
// @Param: CHANNEL
// @DisplayName: Receiver RSSI channel number
// @Description: The channel number where RSSI will be output by the radio receiver (5 and above).
// @Range: 0 16
// @User: Standard
AP_GROUPINFO("CHANNEL", 4, AP_RSSI, rssi_channel, 0),
// @Param: CHAN_LOW
// @DisplayName: RSSI PWM low value
// @Description: PWM value that the radio receiver will put on the RSSI_CHANNEL or RSSI_ANA_PIN when the signal strength is the weakest. Some radio receivers output inverted values so this value may be lower than RSSI_CHAN_HIGH
// @Units: PWM
// @Range: 0 2000
// @User: Standard
AP_GROUPINFO("CHAN_LOW", 5, AP_RSSI, rssi_channel_low_pwm_value, 1000),
// @Param: CHAN_HIGH
// @DisplayName: Receiver RSSI PWM high value
// @Description: PWM value that the radio receiver will put on the RSSI_CHANNEL or RSSI_ANA_PIN when the signal strength is the strongest. Some radio receivers output inverted values so this value may be higher than RSSI_CHAN_LOW
// @Units: PWM
// @Range: 0 2000
// @User: Standard
AP_GROUPINFO("CHAN_HIGH", 6, AP_RSSI, rssi_channel_high_pwm_value, 2000),
AP_GROUPEND
};
// Public
// ------
// constructor
AP_RSSI::AP_RSSI()
{
AP_Param::setup_object_defaults(this, var_info);
if (_s_instance) {
AP_HAL::panic("Too many RSSI sensors");
}
_s_instance = this;
}
// destructor
AP_RSSI::~AP_RSSI(void)
{
}
/*
* Get the AP_RSSI singleton
*/
AP_RSSI *AP_RSSI::get_instance()
{
return _s_instance;
}
// Initialize the rssi object and prepare it for use
void AP_RSSI::init()
{
// a pin for reading the receiver RSSI voltage. The scaling by 0.25
// is to take the 0 to 1024 range down to an 8 bit range for MAVLink
rssi_analog_source = hal.analogin->channel(ANALOG_INPUT_NONE);
}
// Read the receiver RSSI value as a float 0.0f - 1.0f.
// 0.0 represents weakest signal, 1.0 represents maximum signal.
float AP_RSSI::read_receiver_rssi()
{
// Default to 0 RSSI
float receiver_rssi = 0.0f;
switch (rssi_type) {
case RssiType::RSSI_DISABLED:
receiver_rssi = 0.0f;
break;
case RssiType::RSSI_ANALOG_PIN:
receiver_rssi = read_pin_rssi();
break;
case RssiType::RSSI_RC_CHANNEL_VALUE:
receiver_rssi = read_channel_rssi();
break;
case RssiType::RSSI_RECEIVER: {
int16_t rssi = RC_Channels::get_receiver_rssi();
if (rssi != -1) {
receiver_rssi = rssi / 255.0;
}
break;
}
case RssiType::RSSI_PWM_PIN:
receiver_rssi = read_pwm_pin_rssi();
break;
default :
receiver_rssi = 0.0f;
break;
}
return receiver_rssi;
}
// Read the receiver RSSI value as an 8-bit integer
// 0 represents weakest signal, 255 represents maximum signal.
uint8_t AP_RSSI::read_receiver_rssi_uint8()
{
return read_receiver_rssi() * 255;
}
// Private
// -------
// read the RSSI value from an analog pin - returns float in range 0.0 to 1.0
float AP_RSSI::read_pin_rssi()
{
rssi_analog_source->set_pin(rssi_analog_pin);
float current_analog_voltage = rssi_analog_source->voltage_average();
return scale_and_constrain_float_rssi(current_analog_voltage, rssi_analog_pin_range_low, rssi_analog_pin_range_high);
}
// read the RSSI value from a PWM value on a RC channel
float AP_RSSI::read_channel_rssi()
{
RC_Channel *c = rc().channel(rssi_channel-1);
if (c == nullptr) {
return 0.0f;
}
uint16_t rssi_channel_value = c->get_radio_in();
float channel_rssi = scale_and_constrain_float_rssi(rssi_channel_value, rssi_channel_low_pwm_value, rssi_channel_high_pwm_value);
return channel_rssi;
}
void AP_RSSI::check_pwm_pin_rssi()
{
if (rssi_analog_pin == pwm_state.last_rssi_analog_pin) {
return;
}
// detach last one
if (pwm_state.last_rssi_analog_pin) {
if (!hal.gpio->detach_interrupt(pwm_state.last_rssi_analog_pin)) {
gcs().send_text(MAV_SEVERITY_WARNING,
"RSSI: Failed to detach from pin %u",
pwm_state.last_rssi_analog_pin);
// ignore this failure or the user may be stuck
}
}
pwm_state.last_rssi_analog_pin = rssi_analog_pin;
if (!rssi_analog_pin) {
// don't need to install handler
return;
}
// install interrupt handler on rising and falling edge
if (!hal.gpio->attach_interrupt(
rssi_analog_pin,
FUNCTOR_BIND_MEMBER(&AP_RSSI::irq_handler,
void,
uint8_t,
bool,
uint32_t),
AP_HAL::GPIO::INTERRUPT_BOTH)) {
// failed to attach interrupt
gcs().send_text(MAV_SEVERITY_WARNING,
"RSSI: Failed to attach to pin %u",
rssi_analog_pin);
return;
}
}
// read the PWM value from a pin
float AP_RSSI::read_pwm_pin_rssi()
{
// check if pin has changed and configure interrupt handlers if required:
check_pwm_pin_rssi();
if (!pwm_state.last_rssi_analog_pin) {
// disabled (either by configuration or failure to attach interrupt)
return 0.0f;
}
// disable interrupts and grab state
void *irqstate = hal.scheduler->disable_interrupts_save();
const uint32_t irq_value_us = pwm_state.irq_value_us;
pwm_state.irq_value_us = 0;
hal.scheduler->restore_interrupts(irqstate);
const uint32_t now = AP_HAL::millis();
if (irq_value_us == 0) {
// no reading; check for timeout:
if (now - pwm_state.last_reading_ms > 1000) {
// no reading for a second - something is broken
pwm_state.rssi_value = 0.0f;
}
} else {
// a new reading - convert pwm value to rssi value
pwm_state.rssi_value = scale_and_constrain_float_rssi(irq_value_us, rssi_channel_low_pwm_value, rssi_channel_high_pwm_value);
pwm_state.last_reading_ms = now;
}
return pwm_state.rssi_value;
}
// Scale and constrain a float rssi value to 0.0 to 1.0 range
float AP_RSSI::scale_and_constrain_float_rssi(float current_rssi_value, float low_rssi_range, float high_rssi_range)
{
float rssi_value_range = fabsf(high_rssi_range - low_rssi_range);
if (is_zero(rssi_value_range)) {
// User range isn't meaningful, return 0 for RSSI (and avoid divide by zero)
return 0.0f;
}
// Note that user-supplied ranges may be inverted and we accommodate that here.
// (Some radio receivers put out inverted ranges for RSSI-type values).
bool range_is_inverted = (high_rssi_range < low_rssi_range);
// Constrain to the possible range - values outside are clipped to ends
current_rssi_value = constrain_float(current_rssi_value,
range_is_inverted ? high_rssi_range : low_rssi_range,
range_is_inverted ? low_rssi_range : high_rssi_range);
if (range_is_inverted)
{
// Swap values so we can treat them as low->high uniformly in the code that follows
current_rssi_value = high_rssi_range + fabsf(current_rssi_value - low_rssi_range);
std::swap(low_rssi_range, high_rssi_range);
}
// Scale the value down to a 0.0 - 1.0 range
float rssi_value_scaled = (current_rssi_value - low_rssi_range) / rssi_value_range;
// Make absolutely sure the value is clipped to the 0.0 - 1.0 range. This should handle things if the
// value retrieved falls outside the user-supplied range.
return constrain_float(rssi_value_scaled, 0.0f, 1.0f);
}
// interrupt handler for reading pwm value
void AP_RSSI::irq_handler(uint8_t pin, bool pin_high, uint32_t timestamp_us)
{
if (pin_high) {
pwm_state.pulse_start_us = timestamp_us;
} else {
if (pwm_state.pulse_start_us != 0) {
pwm_state.irq_value_us = timestamp_us - pwm_state.pulse_start_us;
pwm_state.pulse_start_us = 0;
}
}
}
AP_RSSI *AP_RSSI::_s_instance = nullptr;
namespace AP {
AP_RSSI *rssi()
{
return AP_RSSI::get_instance();
}
};
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