--- /dev/null
+// Copyright (c) 2017, Tobias Mueller tm(at)tm3d.de
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above copyright
+// notice, this list of conditions and the following disclaimer in the
+// documentation and/or other materials provided with the
+// distribution.
+// * All advertising materials mentioning features or use of this
+// software must display the following acknowledgement: This product
+// includes software developed by tm3d.de and its contributors.
+// * Neither the name of tm3d.de nor the names of its contributors may
+// be used to endorse or promote products derived from this software
+// without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#ifdef __4MHZ__
+#define F_CPU 4000000UL
+#else
+#define F_CPU 8000000UL
+#endif
+#include <avr/io.h>
+
+
+#include <util/delay.h>
+#include <avr/pgmspace.h>
+
+#include "USI_TWI_Master.h"
+#include "SGP30.h"
+//0x58
+#define WC 0b10110000
+#define RC 0b10110001
+#define CRC8_POLYNOMIAL 0x31
+#define CRC8_INIT 0xFF
+#define CRC8_LEN 1
+
+
+uint8_t sensirion_common_generate_crc(uint8_t *data, uint8_t count)
+{
+ uint16_t current_byte;
+ uint8_t crc = CRC8_INIT;
+ uint8_t crc_bit;
+
+ /* calculates 8-Bit checksum with given polynomial */
+ for (current_byte = 0; current_byte < count; ++current_byte) {
+ crc ^= (data[current_byte]);
+ for (crc_bit = 8; crc_bit > 0; --crc_bit) {
+ if (crc & 0x80)
+ crc = (crc << 1) ^ CRC8_POLYNOMIAL;
+ else
+ crc = (crc << 1);
+ }
+ }
+ return crc;
+}
+
+int8_t sensirion_common_check_crc(uint8_t *data, uint8_t count, uint8_t checksum)
+{
+ if (sensirion_common_generate_crc(data, count) != checksum)
+ return 0;
+ return 1;
+}
+
+void readSGPXX(uint16_t com, uint8_t* data, uint8_t len) {
+ I2c_StartCondition();
+ I2c_WriteByte(WC);
+ I2c_WriteByte(com>>8); //Ctrl hum
+ I2c_WriteByte(com&0x00FF); //Ctrl hum
+ _delay_ms(100);
+ I2c_StartCondition();
+ I2c_WriteByte (RC);
+ for(uint8_t i=0;i<len-1;i++) {
+ data[i]=I2c_ReadByte(ACK);
+ }
+ data[len-1]=I2c_ReadByte(NO_ACK);
+ I2c_StopCondition();
+}
+
+void writeSGPXX(uint16_t com, uint8_t* data, uint8_t len) {
+ I2c_StartCondition();
+ I2c_WriteByte(WC);
+ I2c_WriteByte(com>>8); //Ctrl hum
+ I2c_WriteByte(com&0x00FF); //Ctrl hum
+ for(uint8_t i=0;i<len;i++) {
+ I2c_WriteByte(data[i]);
+ }
+ I2c_StopCondition();
+}
+
+
+
+
+
+uint16_t bl1S=0,bl2S=0;
+
+uint16_t getbl=1000;
+
+
+int8_t check_convert_buf(uint8_t *b,uint16_t *v1,uint16_t *v2) {
+ int8_t ret=1;
+ if (sensirion_common_check_crc(b,2,b[2])) { *v1=((int16_t)b[0])<<8|b[1];} else {*v1=0;ret=0;}
+ if (sensirion_common_check_crc(b+3,2,b[5])) {*v2=((int16_t)b[3])<<8|b[4];} else {*v2=0;ret=0;}
+ return ret;
+}
+
+
+
+uint16_t readEEPROM(uint8_t addr,uint16_t def) {
+ uint16_t hr;
+ EEARH=0;
+ while(EECR & (1<<EEPE));
+ EEARL=addr+1;
+ EECR |= (1<<EERE);
+ hr=EEDR;
+ if (hr!=0xFF) {
+ hr=hr<<8;
+ while(EECR & (1<<EEPE));
+ EEARL=addr;
+ EECR |= (1<<EERE);
+ hr|=EEDR;
+ return hr;
+ }
+ return def;
+}
+
+void writeEEPROM(uint8_t addr,uint16_t val) {
+ EEARH=0;
+ while(EECR & (1<<EEPE));
+ EECR = (0<<EEPM1)|(0<<EEPM0);
+ EEARL = addr;
+ EEDR = val&0xFF;
+ EECR |= (1<<EEMPE);
+ EECR |= (1<<EEPE);
+ while(EECR & (1<<EEPE));
+ EECR = (0<<EEPM1)|(0<<EEPM0);
+ EEARL = addr+1;
+ EEDR = val>>8;
+ EECR |= (1<<EEMPE);
+ EECR |= (1<<EEPE);
+}
+
+void save_baseline(uint16_t b1,uint16_t b2 ) {
+ writeEEPROM(0,b1);
+ writeEEPROM(2,b2);
+}
+
+void read_baseline(uint16_t *b1,uint16_t *b2) {
+ *b1=readEEPROM(0,0xFFFF);
+ *b2=readEEPROM(2,0xFFFF);
+}
+
+void set_baseline(uint16_t b1,uint16_t b2) {
+ uint8_t b[10];
+ b[3]=(uint16_t)b1>>8; //irgendwie werden die Werte vertauscht zwischen lesen und schreiben
+ b[4]=(uint16_t)b1&0x00FF;
+ b[5]=sensirion_common_generate_crc(b+3,2);
+ b[0]=(uint16_t)b2>>8;
+ b[1]=(uint16_t)b2&0x00FF;
+ b[2]=sensirion_common_generate_crc(b,2);
+ writeSGPXX(0x201e,b,6);
+ bl1S=b1;
+ bl2S=b2;
+}
+
+int8_t initSGP30() {
+ uint8_t b[10];
+ readSGPXX(0x2032,b,3);
+ _delay_ms(300);
+ writeSGPXX(0x2003,0,0);
+ _delay_ms(10);
+ uint16_t b1=0,b2=0;
+ //set_baseline(0x2210,0x3320);
+ //readSGPXX(0x2015,b,6);
+ read_baseline(&b1,&b2);
+ if (b1!=0xFFFF) {
+ set_baseline(b1,b2);
+ //readSGPXX(0x2015,b,6);
+ //uint16_t bl1,bl2;
+ //check_convert_buf(b,&bl1,&bl2);
+
+ }
+ return 0x1;
+
+}
+
+void runSGP30(uint16_t *CO2,uint16_t *VOC,uint16_t *ETH,uint16_t *H2){
+ uint8_t b[10];
+ readSGPXX(0x2008,b,6);
+ check_convert_buf(b,CO2,VOC);
+ getbl--;
+ if (getbl==0) {
+ uint8_t eq=1;
+ readSGPXX(0x2015,b,6);
+ uint16_t bl1,bl2;
+ check_convert_buf(b,&bl1,&bl2);
+ int8_t bl1d=bl1-bl1S;
+ int8_t bl2d=bl2-bl2S;
+ if (bl1d<0) bl1d=-bl1d;
+ if (bl2d<0) bl2d=-bl2d;
+ if (bl1d>4) {bl1S=bl1;eq=0;}
+ if (bl2d>4) {bl2S=bl2;eq=0;}
+ getbl=200; //Naechste bruefunf in 100 s
+ if (eq==0) {
+ *VOC+=1000;
+ save_baseline(bl1,bl2);
+ }
+ }
+ readSGPXX(0x2050,b,6);
+ check_convert_buf(b,ETH,H2);
+
+}
+
+