Create a new project

Create a new project in MPLAB Xpress for a PIC16F1855 using the MPLAB Xpress Development Board called analogReadSerialWrite.

Instructions are below if this is your first project.

Create A New Project Instructions ►

Create A New Project Instructions ▼

1

Launch the new project wizard

Launch the New Project Wizard using one of the following methods:

• From the Toolbar: Click on the New Project icon , or
• From the Menu: Select File > New Project, or

The project wizard will walk you through the process and prompt you for all the required information. Your selections may be changed after the project has been created by modifying the project's properties.

2

Choose Project

a

Choose 'Microchip Embedded' from the Categories column (center).

b

Choose 'Standalone Project' from the Projects column (right).

c

Click the Next button.

Click image to enlarge.

3

Select Device

a

Choose the device family from the Family drop-down box.

​

If you have used MPLAB^® X IDE previously, choosing 'Recently Used' from the Family drop-down box will filter the 'Device' list to the 3 devices you have used most recently.

b

Choose your device's part number from the Device drop-down box. You may also type in the part number directly, and the list will adjust to the characters you enter.

Click image to enlarge.

4

Select Project Name and Folder

a

Input a project name. This will be your project's name that the IDE will create.

​

Note: The name cannot have any empty spaces!

Click image to enlarge.

---

 How To Create A Project Video

This video shows how to 'Create a Project' in MPLAB Xpress.

---

Open the MPLAB Code Configurator (MCC).

Instructions are below if this is your first project.

Open MCC►

Open MCC ▼

Open the MPLAB® Code Configurator (MCC) under the Tools > Embedded > MPLAB Xpress Code Configurator menu of MPLAB Xpress.

A window will appear showing three steps. If you need the latest version of Java^™ you can click on step one, otherwise, click on the step two button to open the MPLAB^® Xpress Code Configurator.

A file will automatically download in your browser similar to the picture shown. Click on that file to open it. This is a Java application that will launch the MCC.

The process can take several seconds depending on your internet connection speed. Several windows may appear asking if you want to run the program. When the process is complete you will see a new screen appear, separate from the MPLAB Xpress IDE, that is the MCC control screen. In this screen, you can select peripherals for your project, system setup for the oscillator and other configuration settings, input and output selections for your device. When all of these are completed you can generate project code including a main.c file by clicking on the Generate button near the center top of the screen. All these generated files will be included in your MPLAB Xpress project.

---

Set the Clock and Clock Divider

When you open the MCC window, it will open to the System Module window. Increase the HF Internal Clock to 32_MHz and decrease the Clock Divider to 1. Check your screen compared to the window below:

Setting the EUSART

The Bluetooth module will communicate with the PIC16F18855 via serial communication. Therefore, we will take advantage of the EUSART Peripheral to send the RN41 initialization commands serially. Choose EUSART from the Device Resources menu:

Once the window is open, a few settings need to be changed.

1. Check the Enable Transmit box to enable the PIC16F18855 to send information out across the EUSART serial line.
2. Check the Enable EUSART Interrupts because interrupts will be used in the written portion of this program to help with the communication timing between the PIC16F18855 and the RN41.
3. Check the Redirect STDIO to USART box. This allows the use of the Standard IO library which makes code writing an easier process by adding additional functions such as printf, which is used heavily in this program.
4. Increase the Baud Rate to 115200 because this is the speed of communication for the RN41 (found on page 7 here).
5. Check the Enable Continuous Receive because the PIC will be receiving more than one piece of information from the RN41.

ADCC setup

As mentioned in the introduction, this program will take data from an analog potentiometer and feed it to the Bluetooth module. Therefore, we will also need an ADCC module to convert the analog potentiometer values to digital signals. Find the ADCC under Device Resources:

We need to change a few settings in the ADCC.

1. Change the Clock Source to FRC, which will allow the ADCC to run even if the CPU is in sleep mode.
2. Change the Result Alignment to right.

Because the information coming from the ADCC is 10-bits, it must use two 8-bit registers. This changes the order of the output information from the ADCC to right alignment, changing the output values from the leftmost 10 bits of a 16-bit value to the right 10 most bits. What this means for you is that your program can expect values from 0 to 1023 (2⁰ to 2¹⁰) as opposed to values from 2⁷ to 2¹⁶, which will be much more confusing to deal with. Check your finished window with the one below:

Set the Analog Input Pin

You may notice that we only changed two things in the ADCC window, but three places were circled. The third-place highlights an I/O pin name change, specifically the ADCC input channel connected to the potentiometer. To update this, navigate to the Pin Module under Project Resources:

First, close the locks in the pin configurator window as shown. To close a lock, simply click the open lock. The lock will turn green to highlight the pin is selected.

To make the user-written program easier to write, we will also change the names of a few pins by changing the Custom Name in the pin configurator window:

Generating Code

Once you have finished the preliminary setup, choose the Generate option at the top of the page to generate your settings and import them into the MPLAB Xpress. To check that everything uploaded, check your Project box under the Header Files:

You will notice that there are two additional files here: RN41.h and RN41.c. The additional files are part of the Project and Source Files download listed earlier. These two files include a series of functions written to set up all the preliminary settings necessary to communicate with the Bluetooth module. The Bluetooth module is controlled by serial commands sent from the PIC16F18855, and therefore these commands must be added into the project.

Linking the MCC generated code to your application in main.c

Next, the following code needs to be entered into the main.c file that was generated by the MCC. Double click main.c to make sure you are in the correct file. You can also check by looking at which tab is highlighted in the top of the main window:

One word of caution, if the delay functions increase above ~50 μs, it will cause the program to get stuck and stop working. This is due to the byte transfer speed (115200 kps).

Once you have completed writing the program, then it is time to program the microcontroller. Choose the Make and Generate Code button at the top of the IDE window to generate a .hex file.

Then, drag this into your Xpress board that shows up as a USB mass storage device to your computer: