ejung/xmega-modbus-pt100
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measure supply voltage

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This commit is contained in:
Eggert Jung
2020-09-01 05:12:54 +02:00
parent f158e61439
commit 2a8e794741
3 changed files with 17 additions and 9 deletions
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4
newcode/main.c
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@@ -46,14 +46,16 @@ void io_setup(void){
void modbusGet(void) { void modbusGet(void) {
if (modbusGetBusState() & (1<<ReceiveCompleted)) if (modbusGetBusState() & (1<<ReceiveCompleted))
{ {
PORTD.OUTSET = 1 << 5;
switch(rxbuffer[1]) { switch(rxbuffer[1]) {
case fcReadHoldingRegisters: ; case fcReadHoldingRegisters: ;
modbusExchangeRegisters((uint16_t*)ch_values, 0, 18); modbusExchangeRegisters((uint16_t*)ch_values, 0, 20);
break; break;
default: default:
modbusSendException(ecIllegalFunction); modbusSendException(ecIllegalFunction);
break; break;
} }
PORTD.OUTCLR = 1 << 5;
} }
} }

20
newcode/pt100.c
View File

@@ -5,7 +5,7 @@
#include "pt100.h" #include "pt100.h"
uint16_t adc_buffer[AVRG]; uint16_t adc_buffer[AVRG];
volatile float ch_values[9]; volatile float ch_values[10];
void adc_init(void){ void adc_init(void){
ADCA.CTRLB = ADC_FREERUN_bm; ADCA.CTRLB = ADC_FREERUN_bm;
@@ -70,15 +70,21 @@ ISR(DMA_CH0_vect){
ADCA.CTRLB = 0; // stop ADC ADCA.CTRLB = 0; // stop ADC
uint8_t old_pin = pin; uint8_t old_pin = pin;
pin=(pin+1)%9; pin=(pin+1)%10;
ADCA.CH0.MUXCTRL = pin << ADC_CH_MUXPOS_gp; // give MUX time to switch during averaging ADCA.CH0.MUXCTRL = pin << ADC_CH_MUXPOS_gp; // give MUX time to switch during calculation
float temp = avrg(adc_buffer, AVRG); float temp = avrg(adc_buffer, AVRG);
temp = temp - ADC_0V_COUNT; temp = temp - ADC_0V_COUNT;
temp = (temp)/ (4096-ADC_0V_COUNT) * ADC_MAX_VOLT; temp = (temp)/ (4096-ADC_0V_COUNT) * ADC_MAX_VOLT;
temp = (temp * REF_OHMS)/(SUPPLY_VOLTS - temp);
temp = (temp-100)/0.3927; //pt100 formula if(old_pin <= 8){ /* pt100 temperature channels */
ch_values[old_pin] = temp; temp = (temp * REF_OHMS)/(SUPPLY_VOLTS - temp);
temp = (temp-100)/0.3927; //pt100 formula
ch_values[old_pin] = temp;
}
if(old_pin == 9){ /* 24V supply voltage measurement */
// resistor devider 33k and 1k
ch_values[old_pin] = temp * 34;
}
DMA.CH0.TRIGSRC = DMA_CH_TRIGSRC_ADCA_CH0_gc; DMA.CH0.TRIGSRC = DMA_CH_TRIGSRC_ADCA_CH0_gc;
ADCA.CTRLB = ADC_FREERUN_bm; // start ADC again ADCA.CTRLB = ADC_FREERUN_bm; // start ADC again

2
newcode/pt100.h
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@@ -8,7 +8,7 @@
#define ADC_0V_COUNT 170 #define ADC_0V_COUNT 170
#define ADC_MAX_VOLT 1.95 #define ADC_MAX_VOLT 1.95
extern volatile float ch_values[9]; extern volatile float ch_values[10];
void adc_init(void); void adc_init(void);
void dma_init(void); void dma_init(void);