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Diffstat (limited to 'firmware/adc.c')
| -rw-r--r-- | firmware/adc.c | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/firmware/adc.c b/firmware/adc.c new file mode 100644 index 0000000..a9449b7 --- /dev/null +++ b/firmware/adc.c @@ -0,0 +1,200 @@ +/* + * Copyright (c) 2007 empronix (http://www.empronix.com) + * Author: Benedikt Sauter <sauter@empronix.com> + * All rights reserved. + * + * Short descripton of file: + * + * + * 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. + * * Neither the name of the FH Augsburg 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. + */ + +#include "common.h" +#include "protocol.h" +#include "adc.h" + +void adc_parser(char *buf) +{ + switch(buf[0]) + { + case CMD_ADC_INIT_PIN: + adc_init_usb((int)buf[2]); + break; + case CMD_ADC_GET: + adc_get_usb((int)buf[2]); + break; + case CMD_ADC_REF: + adc_ref_usb((int)buf[2]); + break; + + default: + answer[0]=buf[0]; + answer[1]=RSP_UNKOWN_CMD; + answer[2]=0; + CommandAnswer(3); + } +} + +int adc_init(int pin) +{ + if (pin >= 33 && pin <= 40) + { + octopus.ports[pin] = PIN_AD; + + switch(pin) + { + case 40: break; + case 39: break; + case 38: break; + case 37: break; + case 36: break; + case 35: break; + case 34: break; + case 33: break; + default: + return RSP_IMPOSSIBLE_PIN_CONFIG; + } + return RSP_OK; + } + return RSP_UNKOWN_PIN; +} + +void adc_init_usb(int pin) +{ + answer[0]=CMD_ADC_INIT_PIN; + answer[1]= (unsigned char)adc_init(pin); + answer[2]=0; + + CommandAnswer(3); +} + +void adc_get_usb(int pin) +{ + + uint16_t result; + //uint8_t result[2]; + + answer[0]=CMD_ADC_GET; + answer[1]=adc_get(pin,&result); + //result[0] = 0x77; + //result[1] = 0x88; + //answer[2]=(char)result[1]; //high + //answer[3]=(char)result[0]; //low + answer[2]=(char)(result>>8); //high + answer[3]=(char)(result); //low + CommandAnswer(4); +} + + +int adc_get(int pin, uint16_t *value) +{ + *value = 0; + + if (octopus.ports[pin] == PIN_AD) + { + switch (pin) + { + case 40: *value =_adc_read_channel(0); break; + case 39: *value =_adc_read_channel(1); break; + case 38: *value =_adc_read_channel(2); break; + case 37: *value =_adc_read_channel(3); break; + case 36: *value =_adc_read_channel(4); break; + case 35: *value =_adc_read_channel(5); break; + case 34: *value =_adc_read_channel(6); break; + case 33: *value =_adc_read_channel(7); break; + default: + return RSP_IMPOSSIBLE_PIN_CONFIG; + } + return RSP_OK; + } + else + { + return RSP_WRONG_PIN_CONFIG; + } +} + +void adc_ref_usb(int ref) +{ + answer[0]=CMD_ADC_REF; + answer[1]=adc_ref(ref); + CommandAnswer(2); +} + +int adc_ref(int ref) +{ + ADMUX = 0x00; + + switch(ref){ + case PARAM_ADC_AREF: break; + case PARAM_ADC_AVCC: ADMUX |= (1<<REFS0); break; + case PARAM_ADC_INTERNAL: ADMUX |= (1<<REFS1) | (1<<REFS0); break; + default: + return RSP_ERROR; + } + return RSP_OK; +} + +uint16_t _adc_read_channel(int mux) +{ + int i; + uint16_t result; + + ADCSRA = (1<<ADEN) | (1<<ADPS1) | (1<<ADPS0); // Frequenzvorteiler + // setzen auf 8 (1) und ADC aktivieren (1) + + //ADMUX |= (unsigned char)mux; // Kanal waehlen + ADMUX = (ADMUX & 0xF0) | (unsigned char) mux; // select channel + + //ADMUX |= (1<<REFS1) | (1<<REFS0); // interne Referenzspannung nutzen + + /* nach Aktivieren des ADC wird ein "Dummy-Readout" empfohlen, man liest + also einen Wert und verwirft diesen, um den ADC "warmlaufen zu lassen" */ + + ADCSRA |= (1<<ADSC); // eine ADC-Wandlung + while ( ADCSRA & (1<<ADSC) ) { + ; // auf Abschluss der Konvertierung warten + } + result = ADCW; // ADCW muss einmal gelesen werden, + // sonst wird Ergebnis der nächsten Wandlung + // nicht übernommen. + + /* Eigentliche Messung - Mittelwert aus 4 aufeinanderfolgenden Wandlungen */ + result = 0; + for( i=0; i<4; i++ ) + { + ADCSRA |= (1<<ADSC); // eine Wandlung "single conversion" + while ( ADCSRA & (1<<ADSC) ) { + ; // auf Abschluss der Konvertierung warten + } + result += ADCW; // Wandlungsergebnisse aufaddieren + } + ADCSRA &= ~(1<<ADEN); // ADC deaktivieren (2) + + result /= 4; // Summe durch vier teilen = arithm. Mittelwert + + return result; +} |