ap. How to write and test your first program for Microchip MPLAB Xpress Evaluation Board?
MPLAB X v3.25 and XC8 compiler v1.36 or later are needed to compile examples from https://mplabxpress.microchip.com/mplabcloud/example website. But you don't have to install them to your computer, you can test drive the latest Microchip development tools from Microchip Xpress Cloud-based IDE on http://mplabxpress.microchip.com website. The cloud development platform also enables you to register and store your projects and setting.
Xpress board also features an mBUS connector that encompass UART, SPI, interrupt signals and power 3.3 V and 5 V power supply lines. So, a developer can easily add and control its own hardware.
MPLAB Xpress Evaluation Board contains two microcontrollers: PIC18LF25K50 that acts as an USB 2.0 programmers and PIC16F18855 as a development platform. They both are capable of running on a wide range of power supply voltages ranging from 2.3 V to 5.5 V. However, 3.3 V is enough to run both microcontrollers at highest clock frequencies. So, 3.3 V is also used on MPLAB Xpress Evaluation Board.
MPLAB Xpress Evaluation Board is an excellent development platform for beginners. Though 8-bit PIC18F18855 is not the fastest and the most advanced Microchip microcontroller it is still easy to program in all Microchip MPLAB X development environments.
Click on the photo to enlarge it.
Let's return to the MPLAB Xpress Evaluation Board! Programming of PIC16F18855 is done by PIC18F25K50 when a new *.hex file is deposited on its drive named XPRESS. So, one only has to compile a *.hex file for PIC16F18855 and drop it on the XPRESS drive. PIC18LF25K50 based programmer automatically detects the file and programs it to PIC16F18855.
If you want to do a quick comprehensive test of your Microchip MPLAB Xpress Evaluation Board, just download PC USB Projects Xpress Temperature_ADC_and_LED_example.hex from Downloads section. The example includes Temperature sensor reading via simulated COM port on your PC, A/D conversion and LED demonstration. The 10-bitn A/D converted value can also be read through COM port.
Microchip CDC device driver must be installed to use COM port communication. You can obtain the driver from http://mplabxpress.microchip.com website. You also need a terminal emulator software such as Putty, TeraTerm, CoolTerm, … etc. It is also good to know that most of the demonstration projects on https://mplabxpress.microchip.com/mplabcloud/example are designed for MPLAB Xpress Evaluation Board, but not all. However, most transmit data via COM port with the following settings: 19200 bauds, 8 bit, 1 stop bit and no parity or flow control. The same setting must be entered into your terminal emulator configuration to receive text data from PIC16F18855.
Just a question: Do you wonder where PIC18LF25K50 stores 128 kB (kilo bytes) of data? In fact, it doesn’t, because XPRESS is a virtual drive that only exists in a PC memory or cache, to temporary hold a *.hex file before it is programmed into PIC16F18855. If you disconnect your MPLAB Xpress Evaluation Board all the drive contents is gone, except for README.HTM file that exists permanently in PIC18LF25K50 flash RAM.
A READY TO USE EXAMPLE: Plug in your evaluation board and drop the file below on your XPRESS drive!
- PC USB Projects Xpress Temperature_ADC_and_LED_example.hex
BUILD YOUR OWN PIC DEVELOPMENT BOARD:
- Basic circuit for PIC18F24J50 or PIC18F26J50 to work over USB
- Basic circuit for PIC32MX2xxFxxxB to work over USB with an 8.000000 MHz crystal resonator
