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9bc3d2ded0
Signed-off-by: Henry Bruce <henry.bruce@intel.com> Signed-off-by: Abhishek Malik <abhishek.malik@intel.com>
135 lines
2.8 KiB
C++
135 lines
2.8 KiB
C++
#include <iostream>
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#include <unistd.h>
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#include <string.h>
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#include <cmath>
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#include "ds1808lc.h"
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#include "mraa-utils.h"
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#define DS1808_I2C_ADDR 0x28
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#define DS1808_POT2_OFFSET 0x40
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#define DS1808_MAX_POT_VALUE 0x20
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#define DS1808_LOW_VALUE 32 // Lowest pot value that the eye can differentiate from 0
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#define DS1808_HIGH_VALUE 51 // Highest pot value that the eye can differentiate from full
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namespace upm {
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DS1808LC::DS1808LC(int gpioPower, int i2cBus)
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{
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mraa_set_log_level(7);
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pinPower = gpioPower;
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i2c = new mraa::I2c(i2cBus);
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status = i2c->address(DS1808_I2C_ADDR);
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getBrightness();
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}
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DS1808LC::~DS1808LC()
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{
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}
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bool DS1808LC::isPowered()
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{
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return static_cast<bool>(MraaUtils::getGpio(pinPower));
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}
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void DS1808LC::setPowerOn()
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{
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if (!isPowered())
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{
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MraaUtils::setGpio(pinPower, 1);
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setBrightness(0);
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}
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}
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void DS1808LC::setPowerOff()
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{
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MraaUtils::setGpio(pinPower, 0);
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}
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int DS1808LC::getBrightness()
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{
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uint8_t values[2];
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if (i2c->read(values, 2) == 2) {
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return getPercentBrightness(values[0], values[1]);
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}
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else
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UPM_THROW("i2c read error");
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}
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void DS1808LC::setBrightness(int dutyPercent)
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{
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uint8_t values[2];
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values[0] = getPot1Value(dutyPercent);
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values[1] = getPot2Value(dutyPercent);
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status = i2c->write(values, 2);
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if (status != mraa::SUCCESS)
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UPM_THROW("i2c write error");
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}
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//
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// Helper Function
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//
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uint8_t DS1808LC::getPot1Value(int dutyPercent) {
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uint8_t result = 0;
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int scaledResistance = getScaledResistance(dutyPercent);
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if (scaledResistance > DS1808_MAX_POT_VALUE)
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result = DS1808_MAX_POT_VALUE;
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else {
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result = scaledResistance;
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}
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return result;
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}
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uint8_t DS1808LC::getPot2Value(int dutyPercent) {
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uint8_t result = 0;
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int scaledResistance = getScaledResistance(dutyPercent);
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if (scaledResistance <= DS1808_MAX_POT_VALUE)
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result = 0;
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else {
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result = scaledResistance - DS1808_MAX_POT_VALUE;
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}
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if (result > DS1808_MAX_POT_VALUE)
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result = DS1808_MAX_POT_VALUE;
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return result | DS1808_POT2_OFFSET;
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}
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int DS1808LC::getPercentBrightness(uint8_t val1, uint8_t val2) {
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val2 = val2 & (~DS1808_POT2_OFFSET);
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int scaledResistance = val1 + val2;
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int percent;
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if (scaledResistance < DS1808_LOW_VALUE)
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percent = 100;
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else if (scaledResistance > DS1808_HIGH_VALUE)
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percent = 0;
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else
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percent = 100 - (((scaledResistance - DS1808_LOW_VALUE) * 100) / (DS1808_HIGH_VALUE - DS1808_LOW_VALUE));
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return percent;
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}
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int DS1808LC::getScaledResistance(int dutyPercent) {
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int scaledResistance;
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if (dutyPercent == 0)
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scaledResistance = 2 * DS1808_MAX_POT_VALUE;
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else if (dutyPercent == 100)
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scaledResistance = 0;
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else
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scaledResistance = (((100 - dutyPercent) * (DS1808_HIGH_VALUE - DS1808_LOW_VALUE)) / 100) + DS1808_LOW_VALUE;
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return scaledResistance;
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}
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}
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