ardupilot/libraries/SITL/SIM_MS5525.cpp
2021-07-13 12:00:37 +10:00

258 lines
7.5 KiB
C++

#include "SIM_MS5525.h"
#include <SITL/SITL.h>
#include <stdio.h>
using namespace SITL;
MS5525::MS5525() :
I2CDevice()
{
}
void MS5525::reset()
{
// load prom from internal register:
prom_loaded = true;
}
void MS5525::convert_forward(int32_t D1, int32_t D2, float &P_Pa, float &Temp_C)
{
const uint8_t Q1 = Qx_coeff[0];
const uint8_t Q2 = Qx_coeff[1];
const uint8_t Q3 = Qx_coeff[2];
const uint8_t Q4 = Qx_coeff[3];
const uint8_t Q5 = Qx_coeff[4];
const uint8_t Q6 = Qx_coeff[5];
// this is the forward conversion copied from the driver:
int64_t dT = D2 - int64_t(prom[5]) * (1UL<<Q5);
int64_t TEMP = 2000 + (dT*int64_t(prom[6]))/(1UL<<Q6);
int64_t OFF = int64_t(prom[2])*(1UL<<Q2) + (int64_t(prom[4])*dT)/(1UL<<Q4);
int64_t SENS = int64_t(prom[1])*(1UL<<Q1) + (int64_t(prom[3])*dT)/(1UL<<Q3);
int64_t P = (D1*SENS/(1UL<<21)-OFF)/(1UL<<15);
const float PSI_to_Pa = 6894.757f;
P_Pa = PSI_to_Pa * 1.0e-4 * P;
Temp_C = TEMP * 0.01;
}
void MS5525::convert(float P_Pa, float Temp_C, uint32_t &D1, uint32_t &D2)
{
const uint8_t Q1 = Qx_coeff[0];
const uint8_t Q2 = Qx_coeff[1];
const uint8_t Q3 = Qx_coeff[2];
const uint8_t Q4 = Qx_coeff[3];
const uint8_t Q5 = Qx_coeff[4];
const uint8_t Q6 = Qx_coeff[5];
const int64_t TEMP = Temp_C * 100.0f;
const float dT = ((TEMP-2000)*(1UL<<Q6))/prom[6];
const float PSI_to_Pa = 6894.757f;
const float P = P_Pa / (PSI_to_Pa * 1.0e-4);
const int64_t SENS = int64_t(prom[1])*(1UL<<Q1) + (int64_t(prom[3])*dT)/(1UL<<Q3);
const int64_t OFF = int64_t(prom[2])*(1UL<<Q2) + (int64_t(prom[4])*dT)/(1UL<<Q4);
D1 = (((uint64_t(P*(1U<<15)))+OFF)<<21)/SENS;
D2 = dT + int64_t(prom[5]) * (1UL<<Q5);
float f_P_Pa;
float f_Temp_C;
convert_forward(D1, D2, f_P_Pa, f_Temp_C);
if (fabs(f_P_Pa - P_Pa) > 1) {
AP_HAL::panic("Invalid conversion");
}
if (fabs(f_Temp_C - Temp_C) > 0.1) {
AP_HAL::panic("Invalid conversion");
}
}
void MS5525::convert_D1()
{
float pressure = AP::sitl()->state.airspeed_raw_pressure[0];
if (pressure < 0.1) {
// maths breaks down on very, very low numbers, or there's a
// bug in the conversion code. The simulation can pass in
// very, very low numbers. Clamp it.
pressure = 0.1;
}
const float temperature = 25.0f;
uint32_t D1;
uint32_t D2;
convert(pressure, temperature, D1, D2);
convert_out[2] = D1 & 0xff;
D1 >>= 8;
convert_out[1] = D1 & 0xff;
D1 >>= 8;
convert_out[0] = D1 & 0xff;
}
void MS5525::convert_D2()
{
float pressure = AP::sitl()->state.airspeed_raw_pressure[0];
if (pressure < 0.1) {
// maths breaks down on very, very low numbers, or there's a
// bug in the conversion code. The simulation can pass in
// very, very low numbers. Clamp it.
pressure = 0.1;
}
const float temperature = 25.0f;
uint32_t D1;
uint32_t D2;
convert(pressure, temperature, D1, D2);
convert_out[2] = D2 & 0xff;
D2 >>= 8;
convert_out[1] = D2 & 0xff;
D2 >>= 8;
convert_out[0] = D2 & 0xff;
}
void MS5525::update(const class Aircraft &aircraft)
{
const uint32_t now_us = AP_HAL::micros();
// static uint32_t then_us = 0;
// ::fprintf(stderr, "update: s=%u now=%u delta=%u cmd-age=%u\n", (unsigned)state, (unsigned)now_us, (unsigned)(now_us - then_us), (unsigned)(now_us-command_start_us));
// then_us = now_us;
switch (state) {
case State::COLD:
command_start_us = now_us;
prom_loaded = false;
state = State::COLD_WAIT;
break;
case State::COLD_WAIT:
// 1ms to do anything....
if (now_us - command_start_us < 1) {
break;
}
state = State::UNINITIALISED;
FALLTHROUGH;
case State::UNINITIALISED:
break;
case State::RESET_START:
command_start_us = now_us;
state = State::RESET_WAIT;
break;
case State::RESET_WAIT:
// 2ms for reset to complete (data sheet does not specify?)
if (now_us - command_start_us > 2000) {
reset();
state = State::RUNNING;
break;
}
break;
case State::CONVERSION_D1_START:
command_start_us = now_us;
convert_out[0] = 0;
convert_out[1] = 0;
convert_out[2] = 0;
state = State::CONVERSION_D1_WAIT;
break;
case State::CONVERSION_D1_WAIT:
// driver allows for 10ms for a conversion to happen
if (now_us - command_start_us > conversion_time_osr_1024_us) {
convert_D1();
state = State::RUNNING;
break;
}
break;
case State::CONVERSION_D2_START:
command_start_us = now_us;
convert_out[0] = 0;
convert_out[1] = 0;
convert_out[2] = 0;
state = State::CONVERSION_D2_WAIT;
break;
case State::CONVERSION_D2_WAIT:
// driver allows for 10ms for a conversion to happen
if (now_us - command_start_us > conversion_time_osr_1024_us) {
convert_D2();
state = State::RUNNING;
break;
}
break;
case State::RUNNING:
break;
}
// float pressure = AP::sitl()->state.airspeed_raw_pressure[0];
// float temperature = 25.0f;
}
int MS5525::rdwr(I2C::i2c_rdwr_ioctl_data *&data)
{
struct I2C::i2c_msg &msg = data->msgs[0];
// if (data->nmsgs != 1) {
// AP_HAL::panic("nmsgs=%u", data->nmsgs);
// }
if (msg.flags == I2C_M_RD) {
AP_HAL::panic("Read (%u)",msg.len);
return 0;
}
if (msg.len != 1) {
AP_HAL::panic("bad command length");
}
const Command cmd = (Command)msg.buf[0];
if (state != State::RUNNING) {
if (state == State::UNINITIALISED &&
cmd == Command::RESET) {
// this is OK - RESET is OK in UNINITIALISED
} else {
::fprintf(stderr, "Command (0x%02x) received while not running (state=%u)\n", (unsigned)cmd, (unsigned)state);
return -1; // we could die instead...
}
}
switch (cmd) {
case Command::RESET:
state = State::RESET_START;
break;
case Command::READ_C0:
case Command::READ_C1:
case Command::READ_C2:
case Command::READ_C3:
case Command::READ_C4:
case Command::READ_C5:
case Command::READ_C6:
case Command::READ_CRC: {
if (data->msgs[1].len != 2) {
AP_HAL::panic("Unexpected length");
}
const uint8_t addr = ((unsigned)cmd - (unsigned)Command::READ_C0)/2;
const uint16_t val = htobe16(prom[addr]);
data->msgs[1].buf[0] = val & 0xff;
data->msgs[1].buf[1] = val >> 8;
break;
}
case Command::CONVERT_D1_OSR_1024:
state = State::CONVERSION_D1_START;
break;
case Command::CONVERT_D2_OSR_1024:
state = State::CONVERSION_D2_START;
break;
case Command::READ_CONVERSION:
if (data->msgs[1].len == 0) {
// upon not getting a reading back the driver commands a
// conversion-read but doesn't wait for a response!
::fprintf(stderr, "read of length zero\n");
return -1;
}
if (data->msgs[1].len != 3) {
AP_HAL::panic("Unexpected length=%u", data->msgs[1].len);
}
data->msgs[1].buf[0] = convert_out[0];
data->msgs[1].buf[1] = convert_out[1];
data->msgs[1].buf[2] = convert_out[2];
break;
default:
AP_HAL::panic("Unknown command %u (0x%02x)", (unsigned)cmd, (unsigned)cmd);
}
return 0;
}