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--- en:pfw:dht22tmpformat [2025-04-26 20:51] – [A Strange DHT22 Module] mka
+++ en:pfw:dht22tmpformat [2025-04-27 13:39] (current) – [A Strange DHT22 Module] mka
@@ Line 1: / Line 1: @@
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-====== The Document ======
+====== The DHT22 Document ======
 [[https://wiki.forth-ev.de/lib/exe/fetch.php/pfw:am2302-en-aosong.pdf|am2302-en-aosong.pdf]] Although this information is factually correct, I found some of it difficult to understand due to the cumbersome translation into English. **Page 5** provides an example of how to handle the data.
-//Example 1// first shows the interpretation of temperatures above 0 °C and then, as a "special case" the representation of temperatures below 0 °C. Check it out there.
+//Example 1// first shows the interpretation of temperatures above 0 °C and then, as a "special case" the representation of temperatures below 0 °C.((Looks like Sign and Magnitude: The most significant bit (MSB) is used to represent the sign of the number (0 for positive, 1 for negative). The remaining bits indicate the magnitude of the number.))
+ Check it out there.
 ====== The Reality ======
@@ Line 32: / Line 33: @@
 You can see that the MSB in the upper byte is 0, but all other bits are set.
-If you only take the lower byte, it's $72, which is &114. So, -11.4°C should be displayed here. However, this format didn't correspond to the specification in the datasheet. Instead, it resembled a 12-bit two's complement.
+If you only take the lower byte, it's $72, which is &114. So, -11.4°C should be displayed here. However, this format didn't correspond to the specification in the datasheet. Instead, it resembled some 12-bit format.
 Using the logic analyzer, it was possible to verify that this was not a read error during the SDA bitbang, but that the read routine was actually working correctly.