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/**
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* \file ltc2945.cpp
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*
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* \brief Class for LTC2945 power monitor chip.
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*
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* \author Michael Williamson <michael.williamson@criticallink.com>
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*
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* o 0
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* | / Copyright (c) 2014
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* (CL)---o Critical Link, LLC
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* \
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* O
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*/
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#include "ltc2945.h"
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#include "i2c-dev.h"
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#include <stdio.h>
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#include <stdlib.h>
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#define REG_DELTA_SENSE_MSB 0x14
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#define REG_DELTA_SENSE_LSB 0x15
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using namespace MityDSP;
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tcLTC2945::tcLTC2945(int anBus, int anAddr, float Rsens, float Vin)
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: tcI2CDevice(anBus, anAddr)
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, mnVin(Vin)
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, mnRsens(Rsens)
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{
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}
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int tcLTC2945::GetDeltaSense(float& volts)
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{
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int temp, val;
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temp = i2c_smbus_read_byte_data(mnFd, REG_DELTA_SENSE_MSB);
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if (temp < 0)
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{
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perror(__func__);
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return temp;
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}
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val |= temp << 8;
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val &= 0x00FF00;
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temp = i2c_smbus_read_byte_data(mnFd, REG_DELTA_SENSE_LSB);
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if (temp < 0)
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{
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perror("%s:");
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return temp;
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}
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val |= (temp & 0x00FF);
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val >>= 4;
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volts = val * 0.000025;
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return 0;
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}
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int tcLTC2945::Initialize(void)
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{
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int ret;
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char config;
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return Open();
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}
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int tcLTC2945::GetPowerW(float& power)
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{
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int rv;
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float volts;
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rv = GetDeltaSense(volts);
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if (rv)
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return rv;
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float current = volts/mnRsens;
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power = current*mnVin;
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return 0;
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}
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#ifdef LTC2945_APP
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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using namespace MityDSP;
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int main(int argc, char* argv[])
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{
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tcLTC2945* lpTmp;
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int addr = 0x6F; // 110 1111
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int bus = 1;
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int opt;
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opterr = 0;
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int rv;
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float Rsens = 0.01;
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float Vin = 5.00;
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while ((opt = getopt(argc, argv, "a:b:r:v:h")) != -1)
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{
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switch (opt)
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{
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case 'a':
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sscanf(optarg,"%x",&addr);
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break;
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case 'b':
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bus = strtoul(optarg,NULL,10);
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break;
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case 'v':
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sscanf(optarg,"%f", &Vin);
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break;
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case 'r':
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sscanf(optarg,"%f", &Rsens);
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break;
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case 'h': /* '?' */
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default: /* '?' */
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fprintf(stderr, "Usage: %s [-b <busnum>] [-a <addr>] [-v <Vin>] [-r <Rsens>]\n", argv[0]);
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fprintf(stderr, "Defaults: bus = %d, addr=0x%x\n", bus, addr);
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fprintf(stderr, "Defaults: Vin = %f, Rsens=0x%f\n", Vin, Rsens);
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return -1;
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}
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}
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float power;
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float volts;
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lpTmp = new tcLTC2945(bus, addr, Rsens, Vin);
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lpTmp->Initialize();
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rv = lpTmp->GetDeltaSense(volts);
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rv = lpTmp->GetPowerW(power);
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if (rv)
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fprintf(stderr, "unable to read power [%d, 0x%x]\n", rv, rv);
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else
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printf("Read %.5f volts on Vsens, computed power is %.3f W\n", volts, power);
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delete lpTmp;
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return 0;
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}
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#endif
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