DjsBlog: Softata - Adding a new display -6. Run the Display

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Implement the SetUp code and some of the Display methods.

_Now to get the code to do a few things!

The object of this exercise is to provide a template for adding devices, specifically for adding displays to Softata.

The previous post covered testing the display code which had implemnted just th shell of the functionality… That is it works but does nothing. This post covers implementing some of the display’s functionality

1. Links

The repository latest version
The version before the Bargraph was added that is modified in this discussion.
A comparison of the repository before and after this extension is here.
Open the bargraph.ino sketch as per a previous post. We will use copy and use some of the code with minimal modifications. **
2. Setup
In VS Code open the src folder
Open grove_bargraph.cpp
Add the following (in a global manner just below the #includes)

int dataPin = 16;   // Pin connected to DS of 74HC595(Pin14)  
int latchPin = 20;  // Pin connected to ST_CP of 74HC595(Pin12)
int clockPin = 21;  // Pin connected to SH_CP of 74HC595(Pin11)          

Include the following in Custom_Bargraph::Setup() before the return statement:

pinMode(latchPin, OUTPUT);
pinMode(clockPin, OUTPUT);
pinMode(dataPin, OUTPUT);

Connect the display as above
Do another test run as per previous post. It should just run and exit as previous. Nothing to see yet.

3. Write

Add the following to the global space at the top of grove_bargraph.cpp (its a direct copy form bargraph.ino) :

void writeTo595(BitOrder order, byte _data ) {
  // Output low level to latchPin
  digitalWrite(latchPin, LOW);
  // Send serial data to 74HC595
  shiftOut(dataPin, clockPin, order, _data);
  // Output high level to latchPin, and 74HC595 will update the data to the parallel output port.
  digitalWrite(latchPin, HIGH);
}

Then in Custom_Bargraph::WriteString(String msg) insert:

  int num = msg.toInt();
  writeTo595(LSBFIRST, num);

For simplicity for now, assume the Console app does send a valid string.

While we are about it, include the following code for Custom_Bargraph::Clear():

writeTo595(LSBFIRST, 0);

Build and run the Pico app, resolving any build issues.

4. Console App Test

In program.cs locate case CommandType.Displays:
Find if (displayLinkedListIndex < 0)
Then switch (displayDevice)
Collapse the 3 display’s case here. It should look something like:

 switch (displayDevice)
{
    case DisplayDevice.NEOPIXEL:[]
    case DisplayDevice.LCD1602:[]
    case DisplayDevice.OLED096[]
}

Before the closing brace insert the BARGRAPH case:

case DisplayDevice.BARGRAPH:
    break;

Embellish this case with

     Console.WriteLine($"Instantiated {display} linked at {displayLinkedListIndex}");
     SoftataLib.Display.Clear(displayLinkedListIndex);
     Thread.Sleep(1000);
     SoftataLib.Display.WriteString(displayLinkedListIndex, "0x01");
     Thread.Sleep(5000);
     SoftataLib.Display.Clear(displayLinkedListIndex);
     Thread.Sleep(1000);

Rerun (just) the Console app and one LED segment should display for 5 sec.
Now test all segments with:

    case DisplayDevice.BARGRAPH:
        Console.WriteLine($"Instantiated {display} linked at {displayLinkedListIndex}");
        SoftataLib.Display.Clear(displayLinkedListIndex);
        Thread.Sleep(1000);
        SoftataLib.Display.WriteString(displayLinkedListIndex, "1");
        Thread.Sleep(1000);
        SoftataLib.Display.WriteString(displayLinkedListIndex, "2");
        Thread.Sleep(1000);
        SoftataLib.Display.WriteString(displayLinkedListIndex, "4");
        Thread.Sleep(1000);
        SoftataLib.Display.WriteString(displayLinkedListIndex, "8");
        Thread.Sleep(1000);
        SoftataLib.Display.WriteString(displayLinkedListIndex, "16");
        Thread.Sleep(1000);
        SoftataLib.Display.WriteString(displayLinkedListIndex, "32");
        Thread.Sleep(1000);
        SoftataLib.Display.WriteString(displayLinkedListIndex, "64");
        Thread.Sleep(1000);
        SoftataLib.Display.WriteString(displayLinkedListIndex, "128");
        Thread.Sleep(1000);
        SoftataLib.Display.Clear(displayLinkedListIndex);
        Thread.Sleep(1000);
        break;

All good again! :)

5. Custom Setup

This is so any Pico pins can be assigned. Modify and embellish the SetUp methods as follows.

bool Custom_Bargraph::Setup()
{
  byte settings[3];
  settings[0] = 16;
  settings[1] = 20;
  settings[2] = 21;
  return Setup(settings,3);
}

bool Custom_Bargraph::Setup(byte * settings, byte numSettings)
{
 
  if (numSettings >2)
  {
    dataPin = (int)settings[0];
    latchPin = (int)settings[1];
    clockPin = (int)settings[2];
  }
  pinMode(latchPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(dataPin, OUTPUT);
  Serial.begin();
  return true;
}

You can now send an array of 3 bytes to specify the Pico pins for the latch,clock and data pins in that order.

In Program.cs, seraching up, find the line:

// Only do non-default setup for Neopixel

Collapse the line below that:

if (displayDevice == DisplayDevice.NEOPIXEL)
``

- It should look like:

```cs
  if (displayDevice == DisplayDevice.NEOPIXEL)[...]
  else
      displayLinkedListIndex = (byte)SoftataLib.Display.SetupDefault(idisplay);

Insert the following above the else, that is an opton for the BARGRAPH:

  else if (displayDevice == DisplayDevice.BARGRAPH)
  {

      // Use default settings
      //displayLinkedListIndex = (byte)SoftataLib.Display.SetupDefault(idisplay); 
      //Or use custom settings: {data,latch,clock} GPIO Pins
      List<byte> settings = new List<byte> {20,21}; // Send the  data pin as 16
      displayLinkedListIndex = (byte)SoftataLib.Display.Setup(idisplay, 16, settings);
  }

This facilitates using default settings or custom ones. A menu could be used here.

Comment

Note that the other class display methods such as Home are meaningless for this display so are mot embellished beyond returning true. Also, the Misc Flow command could trigger an autonomous continuous display of the successive segments using the Core 2 infrastructure that periodically sends telemetry data.

Conclusion

The Bargarph display has provided a working example of adding a custom display to Softata.

Next: Are we there yet? :)

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