Add READMEs

Hardware/sigrok-decoders/README.md

@@ -0,0 +1,17 @@
+# Sigrok Decoders
+
+Some [sigrok decorders](https://sigrok.org/wiki/Protocol_decoders)
+
+* PCF8574
+* HD44780 (Only 4 bit mode, expecting PCF8574 decoder output)
+
+
+## How to install / use
+
+
+Copy this folder content to:
+
+* On Linux: `~/.local/share/libsigrokdecode/decoders`
+* On Windows: `%ProgramData%\libsigrokdecode\decoders`
+
+And then restart pulseview / sigrok

Hardware/sigrok-decoders/hd44780/README.md

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+# HD44780 LCD Decoder
+
+The HD44780 is a LCD Controller
+
+* Only works in 4 bit mode
+* Expects a PCF8574 compatible output
+

Hardware/sigrok-decoders/hd44780/pd.py

@@ -111,7 +111,7 @@ class Decoder(srd.Decoder):
     )
     options = (
         {'id': 'lcd_mode', 'desc': 'LCD Mode',
-            'default': '4bit', 'values': ('4bit', '8bit')},
+            'default': '4bit', 'values': ('4bit')},
     )
 
     def __init__(self):

Hardware/sigrok-decoders/pcf8574/README.md

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+# PCF8574 Decoder
+
+The PCF8574 is a 8 bit I2C I/O Expander
+
+It receives the input from sigrok i2c decoder and then outputs the raw data that has been written
+
+
+It sends the data to next stack decoder like this:
+
+
+```python
+[
+  [ bitvalue, startsample, endsample ], # Repeats 8 times, one for each bit
+]
+
+# For example:
+[
+  [1, 53636, 53656], # Bit 7
+  [0, 53616, 53636], # Bit 6
+  [0, 53596, 53616], # Bit 5
+  [1, 53576, 53596], # Bit 4
+  [0, 53556, 53576], # Bit 3
+  [0, 53536, 53556], # Bit 2
+  [0, 53516, 53536], # Bit 1
+  [1, 53496, 53516]  # Bit 0
+]
+```