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Support for non 16mhz devices
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Added constructor parameter to allow for different timing needs. It has
the a default value of 6 which is the original value, so it should be
backwards compatible
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soerup committed Dec 29, 2012
1 parent 71ee113 commit ad73fab
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Showing 2 changed files with 5 additions and 4 deletions.
5 changes: 3 additions & 2 deletions DHT.cpp
Expand Up @@ -6,9 +6,10 @@ written by Adafruit Industries

#include "DHT.h"

DHT::DHT(uint8_t pin, uint8_t type) {
DHT::DHT(uint8_t pin, uint8_t type, uint8_t count) {
_pin = pin;
_type = type;
_count = count;
firstreading = true;
}

Expand Down Expand Up @@ -129,7 +130,7 @@ boolean DHT::read(void) {
if ((i >= 4) && (i%2 == 0)) {
// shove each bit into the storage bytes
data[j/8] <<= 1;
if (counter > 6)
if (counter > _count)

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@sej7278

sej7278 Oct 23, 2013

how is this to be used, e.g. for an 8mhz atmega328p? do we halve or double count perhaps?

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@soerup

soerup Oct 23, 2013

Author Contributor

I would expect to halve when you slow down the processor to half speed.

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@sej7278

sej7278 Oct 23, 2013

yup, 3 works but its pretty erratic - sometimes i get 0,2,18 when the actual temperature is 26 (which it correctly reports sometimes).

maybe because i'm putting the mcu to sleep to reduce power usage?

data[j/8] |= 1;
j++;
}
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4 changes: 2 additions & 2 deletions DHT.h
Expand Up @@ -23,13 +23,13 @@ written by Adafruit Industries
class DHT {
private:
uint8_t data[6];
uint8_t _pin, _type;
uint8_t _pin, _type, _count;
boolean read(void);
unsigned long _lastreadtime;
boolean firstreading;

public:
DHT(uint8_t pin, uint8_t type);
DHT(uint8_t pin, uint8_t type, uint8_t count=6);
void begin(void);
float readTemperature(bool S=false);
float convertCtoF(float);
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