Microcontroller based Educational Product:

A 16 bit Micro Experimenter for Solderless Breadboards

The 16 Bit Micro Experimenter is an Innovative solderless breadboard kit solution developed by a Microchip Academic Partner/Microcontroller Educator
for the Practicing Engineer, Hobbyist or Student.
(Web site (www.KibaCorp.com))

The module allows users experimental ease in the exploration and testing of Microchip new series of 16 bit PIC24F Microcontroller using the convenience
of a solderless bread board environment and the ability to reuse existing software applications.
The module supports an ICSP interface for connection to PICKT2 for programming/debug and works seamlessly
with Microchip IDE and PIC 24F language tools. Example Apps:

1. HTTP Web Server

2. FAT16 SD-Card Storage and retrieval

3. 100 year Date/Time Calendar

4. RGB Color palette

5. Thermometer

6. RTOS Multi-task experiments (FREE RTOS (http://www.freertos.org/ ) , PUMPKIN Multi-Tasking SALVO (http://www.pumpkininc.com/))

7. Assortment of other applications

i. Accelerometer, Radio Shack Ranger Finder, RFID, PIR and Servo/Motor experiments

8. Elementary introductory exercises for PIC24F ADC, CCP, UART and Digital ports.

Figure 1 the 16 bit Micro Experimenter shown with PICKIT2

Figure 2 Experimenter Block Diagram

The center piece is Microchip PIC24FJ64GA002 Microcontroller 16 MIPS 3.3V operation. Companion to the PIC24F is a 32KB Serial EEPROM (25LC256) that allows for flexible non-volatile storage as required during program operation to store those necessary items for some applications like calibration data, password or even miniature web page content. The experimenter is equipped with a clock crystal to insure accurate time keeping with the PIC24F internal Real Time Clock Calendar peripheral (RTCC). The Experimenter supports an on-board 16x3 character LCD display and pushbuttons. The Experimenter also provides an I/O expansion bus that is driven by 10 different chip lines originating form the PIC24F. These I/O lines provide ample selection and access to the majority of the PIC24FJ64GA002 on chip peripherals to support a large number of solderless breadboard experiments.

Built –in Demo

The module is equipped with a built-in demo. There are a total of eleven different screens (see figure 3), each lasts about 4 seconds each , and the entire sequence just continuously repeats itself until the operator invokes a demo by pushing one of the pushbuttons.

Figure 3 Flash Screen Auto Sequence

Two introductory demos that come with the kit require some additional hardware and hook-up as shown. A third demo does not rely on any additional hardware. These demos are intended to allow the user familiarity with the Experimenter and insure its proper operation. They can be invoked using the pushbuttons anytime during the flash screen displays and then can return to Flash Displays by simply pressing S4.

Figure 3 Thermometer Demo

1. Button S1-Thermometer

This configures pin 1 of I/O expansion bus to be an analog input and then continuously digitizing this input using the PIC24F internal 10 bit ADC. The results are displayed in degrees Fahrenheit. You need to connect a LM34Z sensor as shown. Please use a raw input of +5VDC for input power to power the sensor. This can be done simply by apply power to the board through the RAW + and - inputs rather then using a wall transformer.

Figure 4 RGB Generator

2. Button S2-RGB Color Generator.

This Demo configures pins 7, 8, 10 to be independent Pulse Generators (using the PIC24F Output Compare Modules) to pulse width modulate separately each of the three LEDS (Read, Green and Blue) of an RGB LED. Each PWM output has a setting of 0-255 which can be set via the LCD and pushbuttons so that you can get 255x255x255 or 16M different colors under this arrangement. Connect a RGB LED as indicated, using 470 ohm resistors in series with each LED anode, and common cathode to ground. An RGB LED source was SPARKFUN (www.sparkfun.com) .To exit and go back to the flash screens simply press S4.

100 Year Clock/Calendar w/ Alarm

Figure 5 100 year Clock/ Calendar w/Alarm

3. Button S3-Clock Calendar

This demo enters a mode where pushbuttons assume clock setting and control operations for internal 100 year real time clock calendar with alarm. User options are: change mode from clock display to clock setting and enter clock changes, stay in clock mode to simply display clock, or exit clock mode back to “Flash Screens”. Designated button functions are as follows:

• Button S1 toggle between clock run mode and clock setting mode

• Button S2 if in clock setting mode increment current data field

• Button S3 if in clock setting mode decrement current data field

• Button S4 advance to next allowable data field if in clock setting mode or if pressed in clock run mode exit to “Flash Screens”

Standalone Application- HTTP Web Server

The Experimenter with the right hardware/software can function as a HTTP web server as one of its stated applications. Microchip originally supplied the stack version 3.75.6 and HTTP server code, but an additional resource for PIC24FJ64GA002 web code, tools and interfaces modules is LJCV Electronics Web site at

http://www.ljcv.net/projects/pic24fj64/index.html

A schematic for other needed electronics is shown using the OLIMEX ENC28J60-H (www.olimex.com) see figure 6. An alternate module is LJVC nic28 module, see LJVC product listings at http://www.ljcv.net/netdev1.html ).

Figure 6 16 Bit Experimenter HTTP Server

Figure 7 shows everything connected on a large solderless breadboard.

Figure 7 16 Bit Experimenter HTTP Servers

This application shows a static web page when an internet browser is opened to the Server’s IP address on your home local network. The Web page HTML data is stored on the Experimenter 25LC256 EEPROM.

The IP address of the module is fixed at 192.168.1.201. The web server supports ping, using the PING command under windows command prompt, you can verify the reply response from the Experimenter.

The 25LC256 EEPROM needs to be programmed with the HTML information. This info is coded in Microchip web page image format. Our web server supports FTP protocol for download load of a web image to Experimenter. Again use command prompt and start an FTP session using ftp 192.168.1.201. For user prompt use ftp and for password prompt use microchip. Use the put command to transfer the web image file into the Experimenter board remotely. Exit the FTP session by typing bye. (See figure 8) Once this is done bring up an internet browser to 192.168.1.201 to see the following web site. (See figure 9). LED should flash once a second to indicate normal operation.

Figure 8 Internet commands to Module

Figure 9 Mini-Web Site

I/O Expansion Bus

The I/O bus is a convenient way of assessing the ports and built-in peripherals of the PIC24F on the Experimenter Module. The pin assignments for the I/O bus are shown. Look at the I/O Expansion Bus Pin descriptions below provided, PIN 7 for instance can be fixed to either analog Input Channel #11 (AN11), or digital change notification #14 (CN14) or simply a digital I/O pin #13 for Port B (RB13). Note that this pin also can be used as RP12, in which case it can be configured by code to be any in or out from any of the major on-chip peripherals (i.e. UART, SPI, Capture Compare to name a few). The makes the I/O expansion bus for the Experimenter a pretty powerful resource for Solderless prototyping.

Building and testing the Experimenter

A kit is made available for purchase that includes PCB and complete parts list (see web site (www.KibaCorp.com))

Assembly is straight forward. You will need a soldering iron, solder, and cutters. All parts are identified in the kit as per part number (i.e. C1, R10).

Figure 10 Board Silkscreen

Identify where the part is located on the PCB by looking at the silkscreen labeling on the board, it will use a similar designator as the part number identified. Insert the part into the designated location from the top, turn the board over (without have the part slip out or move away from the board) and then solder in place at the appropriate PCB pads. Clip the unnecessary lead length. For a number of the IC parts U1, U4 match the notch orientation of the chip package with notch orientation indicated on the PCB, for diode D1, D2 make sure the part orientation for cathode aligns with the cathode designation on the PCB and finally for polarized capacitors like C1, C5, C8, C9 make sure the + terminal is aligned with the + designated pad on the PCB. Always check with the schematic (see figure 9). The .100 headers are installed from the bottom of the board.

One last item the +3V Regulator (U3) bent it to keep it out of the way, but ensure its collector does not touch the board.

Once assembly is completed we need to apply a +6VDC to +9VDC source.

Apply power through wall transformer or through RAW + and -. Turn on the power switch. Since the kit comes with a pre-programmed PIC24FJ64GA002 it should come up with the flash screen come up immediately. Once satisfied with flash screen operation try the demos. Buy a large solderless breadboard (3260 contacts), plug in the Experimenter and add hardware as needed for Thermometer and RGB light demos.

Figure 11 Experimenter Schematic