Commit 266143b0 authored by mmroma's avatar mmroma
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Initial commit.

parent 521eef1b
The MIT License (MIT)
Copyright (c) 2021 Matthew Romano
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
/**
*
* HX711 library for Arduino
* https://github.com/bogde/HX711
*
* MIT License
* (c) 2018 Bogdan Necula
*
**/
#include <Arduino.h>
#include "HX711.h"
// TEENSYDUINO has a port of Dean Camera's ATOMIC_BLOCK macros for AVR to ARM Cortex M3.
#define HAS_ATOMIC_BLOCK (defined(ARDUINO_ARCH_AVR) || defined(TEENSYDUINO))
// Whether we are running on either the ESP8266 or the ESP32.
#define ARCH_ESPRESSIF (defined(ARDUINO_ARCH_ESP8266) || defined(ARDUINO_ARCH_ESP32))
// Whether we are actually running on FreeRTOS.
#define IS_FREE_RTOS defined(ARDUINO_ARCH_ESP32)
// Define macro designating whether we're running on a reasonable
// fast CPU and so should slow down sampling from GPIO.
#define FAST_CPU \
( \
ARCH_ESPRESSIF || \
defined(ARDUINO_ARCH_SAM) || defined(ARDUINO_ARCH_SAMD) || \
defined(ARDUINO_ARCH_STM32) || defined(TEENSYDUINO) \
)
#if HAS_ATOMIC_BLOCK
// Acquire AVR-specific ATOMIC_BLOCK(ATOMIC_RESTORESTATE) macro.
#include <util/atomic.h>
#endif
#if FAST_CPU
// Make shiftIn() be aware of clockspeed for
// faster CPUs like ESP32, Teensy 3.x and friends.
// See also:
// - https://github.com/bogde/HX711/issues/75
// - https://github.com/arduino/Arduino/issues/6561
// - https://community.hiveeyes.org/t/using-bogdans-canonical-hx711-library-on-the-esp32/539
uint8_t shiftInSlow(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder) {
uint8_t value = 0;
uint8_t i;
for(i = 0; i < 8; ++i) {
digitalWrite(clockPin, HIGH);
delayMicroseconds(1);
if(bitOrder == LSBFIRST)
value |= digitalRead(dataPin) << i;
else
value |= digitalRead(dataPin) << (7 - i);
digitalWrite(clockPin, LOW);
delayMicroseconds(1);
}
return value;
}
#define SHIFTIN_WITH_SPEED_SUPPORT(data,clock,order) shiftInSlow(data,clock,order)
#else
#define SHIFTIN_WITH_SPEED_SUPPORT(data,clock,order) shiftIn(data,clock,order)
#endif
HX711::HX711() {
}
HX711::~HX711() {
}
void HX711::begin(byte dout, byte pd_sck, byte gain) {
PD_SCK = pd_sck;
DOUT = dout;
pinMode(PD_SCK, OUTPUT);
pinMode(DOUT, INPUT);
set_gain(gain);
}
bool HX711::is_ready() {
return digitalRead(DOUT) == LOW;
}
void HX711::set_gain(byte gain) {
switch (gain) {
case 128: // channel A, gain factor 128
GAIN = 1;
break;
case 64: // channel A, gain factor 64
GAIN = 3;
break;
case 32: // channel B, gain factor 32
GAIN = 2;
break;
}
digitalWrite(PD_SCK, LOW);
read();
}
long HX711::read() {
// Wait for the chip to become ready.
wait_ready();
// Define structures for reading data into.
unsigned long value = 0;
uint8_t data[3] = { 0 };
uint8_t filler = 0x00;
// Protect the read sequence from system interrupts. If an interrupt occurs during
// the time the PD_SCK signal is high it will stretch the length of the clock pulse.
// If the total pulse time exceeds 60 uSec this will cause the HX711 to enter
// power down mode during the middle of the read sequence. While the device will
// wake up when PD_SCK goes low again, the reset starts a new conversion cycle which
// forces DOUT high until that cycle is completed.
//
// The result is that all subsequent bits read by shiftIn() will read back as 1,
// corrupting the value returned by read(). The ATOMIC_BLOCK macro disables
// interrupts during the sequence and then restores the interrupt mask to its previous
// state after the sequence completes, insuring that the entire read-and-gain-set
// sequence is not interrupted. The macro has a few minor advantages over bracketing
// the sequence between `noInterrupts()` and `interrupts()` calls.
#if HAS_ATOMIC_BLOCK
ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
#elif IS_FREE_RTOS
// Begin of critical section.
// Critical sections are used as a valid protection method
// against simultaneous access in vanilla FreeRTOS.
// Disable the scheduler and call portDISABLE_INTERRUPTS. This prevents
// context switches and servicing of ISRs during a critical section.
portMUX_TYPE mux = portMUX_INITIALIZER_UNLOCKED;
portENTER_CRITICAL(&mux);
#else
// Disable interrupts.
noInterrupts();
#endif
// Pulse the clock pin 24 times to read the data.
data[2] = SHIFTIN_WITH_SPEED_SUPPORT(DOUT, PD_SCK, MSBFIRST);
data[1] = SHIFTIN_WITH_SPEED_SUPPORT(DOUT, PD_SCK, MSBFIRST);
data[0] = SHIFTIN_WITH_SPEED_SUPPORT(DOUT, PD_SCK, MSBFIRST);
// Set the channel and the gain factor for the next reading using the clock pin.
for (unsigned int i = 0; i < GAIN; i++) {
digitalWrite(PD_SCK, HIGH);
#if ARCH_ESPRESSIF
delayMicroseconds(1);
#endif
digitalWrite(PD_SCK, LOW);
#if ARCH_ESPRESSIF
delayMicroseconds(1);
#endif
}
#if IS_FREE_RTOS
// End of critical section.
portEXIT_CRITICAL(&mux);
#elif HAS_ATOMIC_BLOCK
}
#else
// Enable interrupts again.
interrupts();
#endif
// Replicate the most significant bit to pad out a 32-bit signed integer
if (data[2] & 0x80) {
filler = 0xFF;
} else {
filler = 0x00;
}
// Construct a 32-bit signed integer
value = ( static_cast<unsigned long>(filler) << 24
| static_cast<unsigned long>(data[2]) << 16
| static_cast<unsigned long>(data[1]) << 8
| static_cast<unsigned long>(data[0]) );
return static_cast<long>(value);
}
void HX711::wait_ready(unsigned long delay_ms) {
// Wait for the chip to become ready.
// This is a blocking implementation and will
// halt the sketch until a load cell is connected.
while (!is_ready()) {
// Probably will do no harm on AVR but will feed the Watchdog Timer (WDT) on ESP.
// https://github.com/bogde/HX711/issues/73
delay(delay_ms);
}
}
bool HX711::wait_ready_retry(int retries, unsigned long delay_ms) {
// Wait for the chip to become ready by
// retrying for a specified amount of attempts.
// https://github.com/bogde/HX711/issues/76
int count = 0;
while (count < retries) {
if (is_ready()) {
return true;
}
delay(delay_ms);
count++;
}
return false;
}
bool HX711::wait_ready_timeout(unsigned long timeout, unsigned long delay_ms) {
// Wait for the chip to become ready until timeout.
// https://github.com/bogde/HX711/pull/96
unsigned long millisStarted = millis();
while (millis() - millisStarted < timeout) {
if (is_ready()) {
return true;
}
delay(delay_ms);
}
return false;
}
long HX711::read_average(byte times) {
long sum = 0;
for (byte i = 0; i < times; i++) {
sum += read();
// Probably will do no harm on AVR but will feed the Watchdog Timer (WDT) on ESP.
// https://github.com/bogde/HX711/issues/73
delay(0);
}
return sum / times;
}
double HX711::get_value(byte times) {
return read_average(times) - OFFSET;
}
float HX711::get_units(byte times) {
return get_value(times) / SCALE;
}
void HX711::tare(byte times) {
double sum = read_average(times);
set_offset(sum);
}
void HX711::set_scale(float scale) {
SCALE = scale;
}
float HX711::get_scale() {
return SCALE;
}
void HX711::set_offset(long offset) {
OFFSET = offset;
}
long HX711::get_offset() {
return OFFSET;
}
void HX711::power_down() {
digitalWrite(PD_SCK, LOW);
digitalWrite(PD_SCK, HIGH);
}
void HX711::power_up() {
digitalWrite(PD_SCK, LOW);
}
/**
*
* HX711 library for Arduino
* https://github.com/bogde/HX711
*
* MIT License
* (c) 2018 Bogdan Necula
*
**/
#ifndef HX711_h
#define HX711_h
#if ARDUINO >= 100
#include "Arduino.h"
#else
#include "WProgram.h"
#endif
class HX711
{
private:
byte PD_SCK; // Power Down and Serial Clock Input Pin
byte DOUT; // Serial Data Output Pin
byte GAIN; // amplification factor
long OFFSET = 0; // used for tare weight
float SCALE = 1; // used to return weight in grams, kg, ounces, whatever
public:
HX711();
virtual ~HX711();
// Initialize library with data output pin, clock input pin and gain factor.
// Channel selection is made by passing the appropriate gain:
// - With a gain factor of 64 or 128, channel A is selected
// - With a gain factor of 32, channel B is selected
// The library default is "128" (Channel A).
void begin(byte dout, byte pd_sck, byte gain = 128);
// Check if HX711 is ready
// from the datasheet: When output data is not ready for retrieval, digital output pin DOUT is high. Serial clock
// input PD_SCK should be low. When DOUT goes to low, it indicates data is ready for retrieval.
bool is_ready();
// Wait for the HX711 to become ready
void wait_ready(unsigned long delay_ms = 0);
bool wait_ready_retry(int retries = 3, unsigned long delay_ms = 0);
bool wait_ready_timeout(unsigned long timeout = 1000, unsigned long delay_ms = 0);
// set the gain factor; takes effect only after a call to read()
// channel A can be set for a 128 or 64 gain; channel B has a fixed 32 gain
// depending on the parameter, the channel is also set to either A or B
void set_gain(byte gain = 128);
// waits for the chip to be ready and returns a reading
long read();
// returns an average reading; times = how many times to read
long read_average(byte times = 10);
// returns (read_average() - OFFSET), that is the current value without the tare weight; times = how many readings to do
double get_value(byte times = 1);
// returns get_value() divided by SCALE, that is the raw value divided by a value obtained via calibration
// times = how many readings to do
float get_units(byte times = 1);
// set the OFFSET value for tare weight; times = how many times to read the tare value
void tare(byte times = 10);
// set the SCALE value; this value is used to convert the raw data to "human readable" data (measure units)
void set_scale(float scale = 1.f);
// get the current SCALE
float get_scale();
// set OFFSET, the value that's subtracted from the actual reading (tare weight)
void set_offset(long offset = 0);
// get the current OFFSET
long get_offset();
// puts the chip into power down mode
void power_down();
// wakes up the chip after power down mode
void power_up();
};
#endif /* HX711_h */
#ifndef TENSION_PACKET_T_H
#define TENSION_PACKET_T_H
struct __attribute__ ((packed)) tension_packet_t
{
int32_t t_1;
int32_t t_2;
int32_t t_3;
int32_t t_4;
int32_t t_5;
};
#define NUM_FRAMING_BYTES 2 // START & STOP (3 if CRC)
#define _DATA_LENGTH sizeof(tension_packet_t) // Actual Packet Being Sent
#define _PACKET_LENGTH _DATA_LENGTH + NUM_FRAMING_BYTES // Number of bytes in a message
#define START_BYTE 0x1B
#define STOP_BYTE 0xFF
#endif /* TENSION_PACKET_T_H */
#include "HX711.h"
#include "tension_packet.h"
//////////////////////////////////////////////////////////////////////////////////////
// //
// Pin Assignments & Other Globals //
// //
//////////////////////////////////////////////////////////////////////////////////////
#define NUM_LOAD_CELLS 5
int CLK[5] = {2,8,6,4,10};
int DOUT[5] = {3,9,7,5,11};
HX711 load_cells[NUM_LOAD_CELLS];
tension_packet_t the_tension_packet;
char* serialPacket = NULL;
char* dataPacket = NULL;
//////////////////////////////////////////////////////////////////////////////////////
// //
// Setup //
// //
//////////////////////////////////////////////////////////////////////////////////////
void setup() {
Serial.begin(115200);
// 1) Init Each Load Cell
for (int i=0; i < NUM_LOAD_CELLS; i++) {
load_cells[i].begin(DOUT[i], CLK[i]);
}
// 2) Init Serial packet stuff
serialPacket = new char[_PACKET_LENGTH];
serialPacket[0] = START_BYTE;
serialPacket[_PACKET_LENGTH - 1] = STOP_BYTE;
dataPacket = serialPacket + 1;
}
//////////////////////////////////////////////////////////////////////////////////////
// //
// Loop //
// //
//////////////////////////////////////////////////////////////////////////////////////
void loop() {
// 1) Read Each Load Cell
the_tension_packet.t_1 = load_cells[0].read();
the_tension_packet.t_2 = load_cells[1].read();
the_tension_packet.t_3 = load_cells[2].read();
the_tension_packet.t_4 = load_cells[3].read();
the_tension_packet.t_5 = load_cells[4].read();
// 2) Copy the data to the serial packet
memcpy(dataPacket, &the_tension_packet, _PACKET_LENGTH - NUM_FRAMING_BYTES);
// 3) Send the serial packet
Serial.write(serialPacket, _PACKET_LENGTH);
// ~3) Debug the serial packet
// for (int i=0; i < _PACKET_LENGTH; i++) {
// Serial.print(serialPacket[i], HEX);
// }
// Serial.println(' ');
// 4) Block until the write is finished
Serial.flush();
}
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