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Update for 04-11-21 22:15

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Tyler Perkins 2021-11-04 22:15:01 -04:00
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@ -19,3 +19,22 @@ Data is sent using a single bus line. This bus line sends info in the following
manner. manner.
| Humidity int (8b) | Humidity decimal (8b) | Temp int (8b) | Temp decimal (8b) | Parity | | Humidity int (8b) | Humidity decimal (8b) | Temp int (8b) | Temp decimal (8b) | Parity |
Parity is calculated by adding all of the four proceeding values together.
Whatever the result is should match the Parity. The values sent back should be
read as Big Endian; the most signifigant bit comes first for each 8bit block of
data.
== Steps to read Data ==
1) After the DHT11 has been turned on, in must stay on for at least 1S in order
for it to calibrate itself properly. Do not probe it earlier than this.
2) The data line must be held low for *no less than 18ms*. After this time, the
pin on the MCU must switch to being in an input state.
3) The DHT11 will respond with 80us of VCC, followed by 80us of GND. This is
used as a way of calibrating the format in which the device will reply with
data.
4) After this exactly 40bits of data will be sent back. The format for each
type of response is as shown.
- A one (1) consists of 50us of GND, followed by 26-28us of VCC
- A zero (0) consists of 50us of GND, followed by 70us of VCC.