fix ghost channels when used for OUTPUT (#4)

- fix ghost channels when using for OUTPUT - add disable/enable in setChannel() - improve setChannel(), only write changed pins. - update HC4067_performance.ino - update readme.md - update GitHub actions - minor edits
RobTillaart · Apr 3, 2024 · e14e218 · e14e218
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diff --git a/.github/FUNDING.yml b/.github/FUNDING.yml
@@ -1,4 +1,5 @@
 # These are supported funding model platforms
 
 github: RobTillaart
+custom: "https://www.paypal.me/robtillaart"
 
diff --git a/.github/workflows/arduino-lint.yml b/.github/workflows/arduino-lint.yml
@@ -5,8 +5,9 @@ on: [push, pull_request]
 jobs:
   lint:
     runs-on: ubuntu-latest
+    timeout-minutes: 5
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: arduino/arduino-lint-action@v1
         with:
           library-manager: update

diff --git a/.github/workflows/arduino_test_runner.yml b/.github/workflows/arduino_test_runner.yml
@@ -6,12 +6,14 @@ on: [push, pull_request]
 jobs:
   runTest:
     runs-on: ubuntu-latest
+    timeout-minutes: 20
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: 2.6
       - run: |
+          #  sudo sysctl vm.mmap_rnd_bits=28
           gem install arduino_ci
           arduino_ci.rb
diff --git a/.github/workflows/jsoncheck.yml b/.github/workflows/jsoncheck.yml
@@ -9,10 +9,11 @@ on:
 jobs:
   test:
     runs-on: ubuntu-latest
+    timeout-minutes: 5
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: json-syntax-check
-        uses: limitusus/json-syntax-check@v1
+        uses: limitusus/json-syntax-check@v2
         with:
           pattern: "\\.json$"
 
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -6,6 +6,17 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
 
+## [0.2.0] - 2024-04-03
+- fix ghost channels when using for OUTPUT
+  - add disable/enable in setChannel()
+- improve setChannel(), only write changed pins.
+- update HC4067_performance.ino
+- update readme.md
+- update GitHub actions
+- minor edits
+
+----
+
 ## [0.1.2] - 2023-11-04
 - update readme.md
 

diff --git a/HC4067.h b/HC4067.h
@@ -3,15 +3,15 @@
 //    FILE: HC4067.h
 //  AUTHOR: Rob Tillaart
 //    DATE: 2023-01-25
-// VERSION: 0.1.2
+// VERSION: 0.2.0
 // PURPOSE: Arduino library for CD74HC4067 1 x 16 channel multiplexer and compatibles.
 //     URL: https://github.com/RobTillaart/HC4067
 
 
 
 #include "Arduino.h"
 
-#define HC4067_LIB_VERSION         (F("0.1.2"))
+#define HC4067_LIB_VERSION         (F("0.2.0"))
 
 
 class HC4067
@@ -42,16 +42,24 @@ class HC4067
 
   void setChannel(uint8_t channel)
   {
-    if ((channel & 0x0F) != _channel)
+    uint8_t _new = channel & 0x0F;
+    if (_new != _channel)
     {
-      _channel = channel & 0x0F;
+      uint8_t _changed = _new ^ _channel;
       uint8_t mask = 0x08;
       uint8_t i = 3;
+      disable();  //  prevent ghost channels.
       while (mask)
       {
-        digitalWrite(_pins[i--], (mask & _channel));
+        //  only write changed pins. //  AVR only?
+        if (mask & _changed)
+        {
+          digitalWrite(_pins[i--], (mask & _new));
+        }
         mask >>= 1;
       }
+      enable();
+      _channel = _new;
     }
   }
 

diff --git a/LICENSE b/LICENSE
@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2023-2023 Rob Tillaart
+Copyright (c) 2023-2024 Rob Tillaart
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

diff --git a/README.md b/README.md
@@ -22,10 +22,14 @@ multiplexer / demultiplexer and compatible devices.
 The HC4067 allows e.g one analog port read up to 16 different analog channels,
 or one digital port to read the state of 16 buttons.
 
+It is also possible to use the HC4067 to select an OUTPUT channel.
+The signal pin can be connected to VCC (5V) or an IO pin set to OUTPUT.
+Only the selected channel can show the HIGH level of the IO pin if set to HIGH.
+Not selected pins will all be set to LOW.
 
-The channel selection is done with four select lines **S0..S3**
+The channel selection is done with four select lines **S0..S3**.
 
-The device can be enabled/disabled by the enable line **E**
+The device can be enabled/disabled by the enable line **E**.
 
 
 #### Compatibles
@@ -40,14 +44,16 @@ Not tested, considered compatible.
 - https://github.com/RobTillaart/HC4052  (2x4 mux)
 - https://github.com/RobTillaart/HC4053  (3x2 mux)
 - https://github.com/RobTillaart/HC4067  (1x16 mux)
+- https://github.com/RobTillaart/MAX14661 (2x16 mux, I2C)
+- https://tronixstuff.com/2013/08/05/part-review-74hc4067-16-channel-analog-multiplexerdemultiplexer/
 
 
 ## Hardware connection
 
-Typical connection is to connect the four **select pins** to four IO Pins of your board.
+Typical connection is to connect the four **select pins** to four IO pins of your board.
 
-The optional **enablePin E** must be connected to GND if not used.
-This way the device is continuous enabled.
+The optional **enablePin E** must be connected to **GND** if not used.
+This way the device will be continuous enabled.
 
 Example multiplexing analog in.
 
@@ -76,6 +82,25 @@ Example multiplexing analog in.
 ```
 
 
+#### Less Select lines
+
+Note: the library does not meant for this mode, although it should work.
+The GND-ed pins should be set to 255 (not tested).
+
+It is possible to use less IO pins to connect to the S0..S3.
+The ones not connected to an IO pin must be connected to GND (preferred).
+
+|  S0   |  S1   |  S2   |  S3   |  pins  |  notes  |
+|:-----:|:-----:|:-----:|:-----:|:------:|:-------:|
+|  IO   |  IO   |  IO   |  IO   |  0-15  |  default usage
+|  IO   |  IO   |  IO   |  GND  |   0-7  |
+|  IO   |  IO   |  GND  |  GND  |   0-3  |
+|  IO   |  GND  |  GND  |  GND  |   0-1  |
+
+Of course it is possible to set a Select pin to VCC instead of GND.
+This will result in another subset of the Y pins to select from.
+
+
 ## Interface
 
 ```cpp
@@ -89,50 +114,41 @@ Set the 4 select pins and optional the enable pin.
 If the enablePin == 255 it is considered not used.
 - **void setChannel(uint8_t channel)** set the current channel.
 Valid values 0..15, this value is not checked, only the lower 4 bits will be used.
-- **uint8_t getChannel()** get current channel 0..15.
+- **uint8_t getChannel()** returns the current channel 0..15.
+The selected channel is also returned when the multiplexer is disabled.
 
 
 #### Enable
 
 These functions work only if enablePin is set in the constructor.
 
-- **void enable()** idem.
-- **void disable()** idem.
-- **bool isEnabled()** idem.
-Also returns true if enablePin is not set.
+- **void enable()** enables the HC4067 to multiplex.
+- **void disable()** disables the HC4067, no channel is selected.
+- **bool isEnabled()** returns the current status of the HC4067.
+Also returns true if the enablePin is not set in the constructor.
 
 
 ## Future
 
 #### Must
 
-- elaborate documentation
-  - links etc.
-
+- documentation
 
 #### Should
 
-- optimizations
-  - performance setChannel
-- investigate how to use with only 3 lines or 2 lines.
-  - set s3 / s2 to LOW always or so
-
+- test performance **setChannel()** on ESP32 / fast board.
+  - should optimized version be AVR only?
 
 #### Could
 
 - next() and prev() as channel selector.
-  - internal channel variable needed.
-- move code to .cpp file
-- investigate
-  - can it be used as 16 channel OUTPUT (yes but)
-  - is it buffered?
-
+  - what to do with range borders? ==> stop?
 
 #### Won't (unless requested)
 
-- optimizations
-  - only do digitalWrite when changed? gain is minimal.
-  - now takes 24 micros on UNO if set.
+- check channel in setChannel() ?
+  - return true if in range, false otherwise.
+- move code to .cpp file
 
 
 ## Support

diff --git a/examples/HC4067_16_buttons/HC4067_16_buttons.ino b/examples/HC4067_16_buttons/HC4067_16_buttons.ino
@@ -7,11 +7,12 @@
 
 #include "HC4067.h"
 
-HC4067 mp(4, 5, 6, 7);
+HC4067 mp(4, 5, 6, 7);  //  no enable pin defined connect to GND.
 
 const int inputPin = 10;
 uint16_t values;
 
+
 void setup()
 {
   Serial.begin(115200);

diff --git a/examples/HC4067_4_channel_plotter/HC4067_4_channel_plotter.ino b/examples/HC4067_4_channel_plotter/HC4067_4_channel_plotter.ino
@@ -14,11 +14,12 @@
 
 //  4..7 channel select pins
 //  8 = enable pin
-HC4067 mp(4, 5, 6, 7, 8);  
+HC4067 mp(4, 5, 6, 7, 8);
 
 
 uint32_t lastTime = 0;
 
+
 void setup()
 {
   Serial.begin(115200);

diff --git a/examples/HC4067_demo/HC4067_demo.ino b/examples/HC4067_demo/HC4067_demo.ino
@@ -6,7 +6,7 @@
 
 #include "HC4067.h"
 
-HC4067 mp(4, 5, 6, 7);
+HC4067 mp(4, 5, 6, 7);  //  no enable pin defined connect to GND.
 
 
 void setup()
@@ -26,9 +26,11 @@ void loop()
   for (uint8_t channel = 0; channel < 16; channel++)
   {
     mp.setChannel(channel);
-    Serial.println(analogRead(A0));
+    Serial.print(analogRead(A0));
+    Serial.print("\t");
     delay(100);
   }
+  Serial.println();
 }
 
 

diff --git a/examples/HC4067_performance/HC4067_performance.ino b/examples/HC4067_performance/HC4067_performance.ino
@@ -6,32 +6,42 @@
 
 #include "HC4067.h"
 
-HC4067 mp(4, 5, 6, 7);
+HC4067 mp(4, 5, 6, 7, 8);
 
 uint32_t start, stop;
 
+
 void setup()
 {
   Serial.begin(115200);
   Serial.println(__FILE__);
   Serial.print("HC4067 LIBRARY VERSION: ");
   Serial.println(HC4067_LIB_VERSION);
   Serial.println();
+  delay(100);
 
-  delay(1000);
-  start = micros();
   mp.setChannel(10);
-  stop = micros();
+
+  for (uint8_t ch = 0; ch < 16; ch ++)
+  {
+    start = micros();
+    mp.setChannel(ch);
+    stop = micros();
+    Serial.print("Channel ");
+    Serial.print(ch);
+    Serial.print(": \t");
+    Serial.println(stop - start);
+    delay(100);
+  }
 
-  Serial.print("SetChannel: \t");
-  Serial.println(stop - start);
+  mp.setChannel(10);
   delay(100);
 
   start = micros();
   mp.setChannel(10);
   stop = micros();
 
-  Serial.print("SetChannel: \t");
+  Serial.print("\nSetChannel: \t");
   Serial.println(stop - start);
   delay(100);
 

diff --git a/examples/HC4067_performance/output_0.2.0.txt b/examples/HC4067_performance/output_0.2.0.txt
@@ -0,0 +1,22 @@
+
+HC4067_performance.ino
+HC4067 LIBRARY VERSION: 0.2.0
+
+Channel 0: 	24
+Channel 1: 	20
+Channel 2: 	28
+Channel 3: 	20
+Channel 4: 	32
+Channel 5: 	20
+Channel 6: 	24
+Channel 7: 	24
+Channel 8: 	36
+Channel 9: 	20
+Channel 10: 	24
+Channel 11: 	20
+Channel 12: 	32
+Channel 13: 	24
+Channel 14: 	24
+Channel 15: 	20
+
+SetChannel: 	8
diff --git a/examples/HC4067_test/HC4067_test.ino b/examples/HC4067_test/HC4067_test.ino
@@ -6,7 +6,7 @@
 
 #include "HC4067.h"
 
-HC4067 mp(4, 5, 6, 7, 8);  //  explicitly set enable pin
+HC4067 mp(4, 5, 6, 7, 8);  //  explicitly set enable pin (8)
 
 
 void setup()