Using the CLC JK FlipFlop to Control an I/O Port

Create a new project and select the PIC16F1619 along with the Curiosity Board and MPLAB XC8 compiler. ​

Open the MPLAB Code Configurator (MCC) under the Tools > Embedded menu of MPLAB X IDE.

From Project Resources choose System Module to open the System Setup window within MCC.

• In the clock settings, make sure you select INTOSC
• Select the system clock FOSC.
• Set Internal Clock to the 4MHz_HF setting.
• Check the PLL Enabled box.
• The Curiosity Board uses a programmer/debugger on board (PKOB) and uses a Low Voltage Program method to program the MCU, therefore we must enable low-voltage programming by checking the Low-voltage programming Enable box.

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Add the TMR6 peripheral to the project from the Device Resources area of MCC by scrolling down to the Timer entry and expand the list by clicking on the arrow. Now double click-on the TMR6 entry to add it to the Project Resources list. Then click on the TMR6 to open the Timer 6 configuration setup screen.

1. Check the Enable Timer box
2. Select Clock Source LFINTOSC, Postscaler 1:1, and Prescaler 1:32
3. Set Timer period value to "100.129 ms"
4. Set External Reset Source to T6IN, and Control mode setting to Roll over pulse,
5. Set Start/Reset Option to Software Control (this will inhibit hardware reset of timer).
6. Leave the Enable Timer Interrupt box unchecked.

Add the CLC1 peripheral to the project from the Device Resources area of MCC by scrolling down to the CLC entry and expand the list by clicking on the arrow. Now double click-on the CLC1 entry to add it to the Project Resources. Then click on the CLC1 to open the Timer 6 configuration setup screen.

Select the J-K Flip-Flop with R tab from the logic functions (mode) list. Let’s connect J and K to a high logic level. The logic diagram can be modified by just clicking on the connections.

1. Set first input signal to T6_postscaled_out
2. Connect the first input signal to Gate 1 by clicking on the input line to Gate 1.
3. Set Gate 2 and Gate 4 outputs to Inverted by clicking on the output line.

With the inputs of Gate 2 and Gate 4 grounded and then the output inverted this sets the J and K inputs of the JK flip-flop to always high. The R pin is set low by Gate 3 setup which didn't require any changes from the default.

Connecting I/O pin

The output of the CLC JK Flip Flop needs to be connected to the LED. We can do that using the Peripheral Pin Select (PPS) feature built into the device. The MCC does the setup code for us so all that is needed is to change the blue lock for the PortC 5 pin to green in the CLC1OUT row of the Pin Manager Grid. This will connect the output of the Flip-FlopFlop to the I/O pin using the PPS.

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Click on the Generate button in the Project Resources of the MCC screen to have the MCC create the drivers and a base main.c file for the project.

The generated main.c file doesn't need any additional code because this application runs within the core-independent peripheral hardware separate from the CPU.

Click on Build Project (hammer icon) to compile the code and you will see a "BUILD SUCCESSFUL" message in the output window of MPLAB X within several seconds of processing time.

BUILD SUCCESSFUL (total time: 8s)

Make sure your Curiosity Board is connected to the USB port. Then, click on Make and Program Device. This will build the project again and launch the programmer built into the Curiosity Board. In the Output window, you should see a series of messages and when successful it will end with a "Programming and Verify Successful" message.

Output Window:

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