added hx711 support

devLib/hx711.c

@@ -0,0 +1,155 @@
+#include <stdio.h>
+#include <inttypes.h>
+#include <wiringPi.h>
+
+#include "hx711.h"
+
+//channel A, gain 128
+#define GAIN_128 128
+
+//channel A, gain 64
+#define GAIN_64 64
+
+//channel B, gain 32
+#define GAIN_32 32
+
+uint8_t sGainBits[256];
+float sScale[256];
+int sOffset[256];
+
+uint8_t sClockPin[256];
+uint8_t sDataPin[256];
+
+uint8_t hx711Setup(uint8_t clockPin, uint8_t dataPin, uint8_t skipSetup, uint8_t instId)
+{
+	sGainBits[instId] = 1;
+	sScale[instId] = 1.0f;
+	sOffset[instId] = 0;
+	sClockPin[instId] = clockPin;
+	sDataPin[instId] = dataPin;
+	if ((!skipSetup) && wiringPiSetup() == -1)
+	{
+		printf("initialization failed");
+		return 255;
+	}
+	pinMode(sClockPin[instId], OUTPUT);
+	pinMode(sDataPin[instId], INPUT);
+	return 0;
+}
+
+uint8_t hx711IsReady(uint8_t instId)
+{
+	return digitalRead(sDataPin[instId]) == LOW;
+}
+
+void hx711SetGain(uint8_t gain, uint8_t instId)
+{
+	switch (gain)
+	{
+	case GAIN_128:
+		sGainBits[instId] = 1;
+		break;
+	case GAIN_64:
+		sGainBits[instId] = 3;
+		break;
+	case GAIN_32:
+		sGainBits[instId] = 2;
+		break;
+	default:
+		//invalid gain, ignore
+		break;
+	}
+
+	digitalWrite(sClockPin[instId], LOW);
+	hx711Read(instId);
+}
+
+int hx711Read(uint8_t instId)
+{
+	// wait for the chip to become ready
+	while (!hx711IsReady(instId))
+		;
+
+	int data = 0;
+	// pulse the clock pin 24 times to read the data
+	for (uint8_t i = 24; i--;)
+	{
+		digitalWrite(sClockPin[instId], HIGH);
+
+		digitalRead(sDataPin[instId]);
+		data |= (digitalRead(sDataPin[instId]) << i);
+
+		digitalWrite(sClockPin[instId], LOW);
+	}
+
+	// set the channel and the gain factor for the next reading using the clock pin
+	for (int i = 0; i < sGainBits[instId]; i++)
+	{
+		digitalWrite(sClockPin[instId], HIGH);
+		digitalWrite(sClockPin[instId], LOW);
+	}
+
+	if (data & 0x800000)
+	{
+		data |= (long)~0xffffff;
+	}
+
+	return data;
+}
+
+int hx711ReadAverage(uint8_t times, uint8_t instId)
+{
+	int64_t sum = 0;
+	for (uint8_t i = 0; i < times; i++)
+	{
+		sum += hx711Read(instId);
+	}
+	return sum / times;
+}
+
+int hx711GetRawValue(uint8_t times, uint8_t instId)
+{
+	return hx711ReadAverage(times, instId) - sOffset[instId];
+}
+
+float hx711GetUnits(uint8_t times, uint8_t instId)
+{
+	return hx711GetRawValue(times, instId) / sScale[instId];
+}
+
+void hx711Tare(uint8_t times, uint8_t instId)
+{
+	uint64_t sum = hx711ReadAverage(times, instId);
+	hx711SetOffset(sum, instId);
+}
+
+void hx711SetScale(float scale, uint8_t instId)
+{
+	sScale[instId] = scale;
+}
+
+void hx711SetOffset(int offset, uint8_t instId)
+{
+	sOffset[instId] = offset;
+}
+
+void hx711PowerDown(uint8_t instId)
+{
+	digitalWrite(sClockPin[instId], LOW);
+	digitalWrite(sClockPin[instId], HIGH);
+}
+
+void hx711PowerUp(uint8_t instId)
+{
+	digitalWrite(sClockPin[instId], LOW);
+}
+
+int hx711GetOffset(uint8_t instId)
+{
+	return sOffset[instId];
+}
+
+float hx711GetScale(uint8_t instId)
+{
+	return sScale[instId];
+}

devLib/hx711.h

@@ -0,0 +1,56 @@
+
+/*
+ * hx711.h:
+ * 24-Bit Analog-to-Digital Converter (ADC) for weight measure
+ * Adaptation of https://github.com/pommoisel/HX711
+ *
+ * Copyright (c) 2013 Gordon Henderson.
+ ***********************************************************************
+ * This file is part of wiringPi:
+ *	https://projects.drogon.net/raspberry-pi/wiringpi/
+ *
+ *    wiringPi is free software: you can redistribute it and/or modify
+ *    it under the terms of the GNU Lesser General Public License as published by
+ *    the Free Software Foundation, either version 3 of the License, or
+ *    (at your option) any later version.
+ *
+ *    wiringPi 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 Lesser General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Lesser General Public License
+ *    along with wiringPi.  If not, see <http://www.gnu.org/licenses/>.
+ ***********************************************************************
+ */
+
+#ifndef _HX711_H_
+#define _HX711_H_
+
+#include <inttypes.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern uint8_t hx711Setup(uint8_t clockPin, uint8_t dataPin, uint8_t skipSetup, uint8_t instId);
+extern uint8_t hx711IsReady(uint8_t instId);
+extern void hx711SetGain(uint8_t gain, uint8_t instId);
+extern int hx711Read(uint8_t instId);
+
+extern int hx711ReadAverage(uint8_t times, uint8_t instId);
+extern int hx711GetRawValue(uint8_t times, uint8_t instId);
+extern float hx711GetUnits(uint8_t times, uint8_t instId);
+extern void hx711Tare(uint8_t times, uint8_t instId);
+extern void hx711SetScale(float scale, uint8_t instId);
+extern void hx711SetOffset(int offset, uint8_t instId);
+extern void hx711PowerDown(uint8_t instId);
+extern void hx711PowerUp(uint8_t instId);
+extern int hx711GetOffset(uint8_t instId);
+extern float hx711GetScale(uint8_t instId);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif //_HX711_H_