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109 lines
2.9 KiB
C
109 lines
2.9 KiB
C
#include <avr/io.h>
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#include <avr/interrupt.h>
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#include <util/delay.h>
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#include "modbus.h"
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#define HIGH_LOW_CYCLE_TIME 1
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uint16_t holdingRegisters[4];
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void timer0100us_start(void) {
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TCCR0B|=(1<<CS01); //prescaler 8
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TIMSK0|=(1<<TOIE0);
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}
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//Return raw ADC data
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uint32_t HX711_get_data(uint8_t clk_PIN, uint8_t data_PIN, uint8_t gain_for_next_conv){
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uint32_t data = 0;
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for(uint8_t i = 0; i < 24; i++){ //Start 24bit transmission
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PORTB |= (1 << clk_PIN); //Set clock-PIN high
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_delay_us(HIGH_LOW_CYCLE_TIME);
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/* Shift data to free LSB. Operation placed before writing data to avoid
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manuell shiftig after loop finsihed.*/
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data <<= 1;
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/* Shift input-status of data containing bit to the
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LSB and set all other bits to 0. Add result to
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currently LSB in data-var.*/
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data |= ((PINB>>data_PIN) & 0x01); //Read and store data
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PORTB &= ~(1 << clk_PIN); //Set clock-PIN low
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_delay_us(HIGH_LOW_CYCLE_TIME);
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}
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/* Add extra clk-pluses to set PGA-Gain for next conversion
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1 extra pulse : Channel A Gain = 128
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2 extra pluses: Channel B Gain = 32
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3 extra pluses: Channel A Gain = 64*/
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int8_t extra_clk_pluses = 1;
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switch(gain_for_next_conv){
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case 128:
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extra_clk_pluses = 1;
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break;
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case 64:
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extra_clk_pluses = 3;
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break;
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case 32:
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extra_clk_pluses = 2;
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break;
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default:
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extra_clk_pluses = 1;
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}
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for(uint8_t i = 0; i < extra_clk_pluses; i++){
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PORTB |= (1 << clk_PIN); //set clock-PIN high
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_delay_us(HIGH_LOW_CYCLE_TIME);
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PORTB &= ~(1 << clk_PIN); //set clock-PIN low
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_delay_us(HIGH_LOW_CYCLE_TIME);
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}
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/* Convert 24bit Two's complement to 32bit Two's complement
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if MSB from 24Bit result is 1 aka negative*/
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if(data & (1L<<23)){
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data |= 0xFFL << 24;
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}
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return data;
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}
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void modbusGet(void) {
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if (modbusGetBusState() & (1<<ReceiveCompleted))
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{
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switch(rxbuffer[1]) {
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case fcReadHoldingRegisters:
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PORTC ^= 1 << 1;
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// _delay_ms(10);
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// PORTC &= ~(1 << 1);
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uint32_t tmp = HX711_get_data(3, 4, 128);
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//int32_t tmp = -1000;
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holdingRegisters[0] = tmp & 0xFFFF;
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holdingRegisters[1] = (tmp>>16) & 0xFFFF;
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modbusExchangeRegisters(holdingRegisters,0,4);
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break;
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default: {
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modbusSendException(ecIllegalFunction);
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}
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break;
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}
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}
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}
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int main(void){
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DDRC |= 3 << 0;
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DDRB |= (1<<3);
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modbusSetAddress(1);
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modbusInit();
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sei();
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timer0100us_start();
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while(1){
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modbusGet();
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//PORTC ^= 1 << 0;
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//_delay_ms(100);
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//PORTC &= ~(1 << 1);
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}
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}
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ISR(TIMER0_OVF_vect) { //this ISR is called 9765.625 times per second
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modbusTickTimer();
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}
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