Homebrew PIC Experimenter Board

Discussion in 'Embedded Systems and Microcontrollers' started by mikejp56, Dec 16, 2015.

  1. mikejp56

    Thread Starter Member

    Jun 14, 2015
    49
    1
    Hi All,
    After browsing the Micro Electronics Lab website and doing research on Google, I was inspired to design and build my own PIC experimenter's board. It will have the following:
    40 Pin ZIF Socket
    8 LEDs
    4 Pushbutton switches
    2x16 LCD display
    USB programmer
    64K I2C EEPROM
    Temperature and Humidity sensors
    Potentiometer for 0-5V analog input
    Piezoelectric buzzer

    The ZIF socket will be wired for a 16F887, with all of the port connections coming out to female headers. The peripherals will also have female header connectors for easy interconnects.
    Other PICs will be available for use by inserting them into an interface board wired with different sized sockets. The interface board will have 40 pins that plug into the ZIF socket, allowing any PIC to have access to any of the port pins and any of the peripherals. The only restriction to the use of the interface board is that only the PIC in use can be plugged into its socket; the other sockets cannot be populated.
    I will post schematics and a bill of materials soon.
    regards,
    mike
     
  2. spinnaker

    AAC Fanatic!

    Oct 29, 2009
    4,887
    1,017
    If you really want to make it flexible look at j1sys.com Maybe you can use their sockets or just their idea. They sell a set of configurable zif sockets that allow you to use just about any Pic. Pretty cool.
     
  3. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,570
    2,381
    Have you also looked at the Picmicro demo board for comparative features?
    It has 18, 28 & 40 pin sockets, Usart port, optional Xtal for main clock and 32Khz T1 clk.
    I changed the LCD wiring one the one I have to enable optional pins for the LCD instead of dedicated as it comes.
    Also I don't miss the Zif sockets as it has the ICP header.
    Max.
     
  4. mikejp56

    Thread Starter Member

    Jun 14, 2015
    49
    1
    Here are the schematics and a bill of materials for the PIC Experimenter board. One thing that I forgot to mention in my first post has to do with the USB Programmer. The schematic, firmware, and programming software are available from Circuits Gallery. A google search will find the link to "How to build your own USB PIC programmer." I will post schematics for the adapter board soon.
    Regards,
    Mike
     
  5. spinnaker

    AAC Fanatic!

    Oct 29, 2009
    4,887
    1,017
    Don't build your own. Buy a PicKit3 or at least a 2. You will be a LOT happier not pulling out your hair.
     
    MaxHeadRoom likes this.
  6. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    7,395
    1,607
    What do you use to program the PIC in your PIC programmer? Do you use the chicken or the egg?

    What do you have against in circuit programmer/debuggers?

    Wow, I haven't seen an alphanumeric LCD use 8 data lines in near a decade.
     
  7. mikejp56

    Thread Starter Member

    Jun 14, 2015
    49
    1
    Hi spinnaker,
    I am an electronic tech with 30+ years experience. I know how to read schematics, build and troubleshoot circuits to the component level, and I enjoy building stuff. Like I said in my first post, I was browsing the MEL website and forums, and was inspired to build my own. For an experienced ET, this project is a simple build; and it is very rewarding to design and build something that will teach me about something new to me, like PICs.

    Hi ErnieM,
    If you think back a few months I was the one asking about JDM progammers. Well I was able to use a homebrew JDM programmer to program the 18F2550 used in the USB programmer. I just kept moving forward and ended up here.
    As for the LCD it is a standard 44780 based LCD. It works fine with only 4 bits. I wired out all 8 bits for the sake of completeness.

    This is a board for experimenting with and learning about PICs. I just wanted to show what can be done with some junkbox parts and the will to do something.

    Regards,
    Mike
     
  8. nerdegutta

    Moderator

    Dec 15, 2009
    2,519
    786
    Hi, a few comments/thoughts of you schematics:

    PIC experimenter board:
    I can not see a variable resistor on the LCD. It should be something on pin 3. Or at least a comment of it.
    The datalines from the LCD has the same names as the LEDs. That could be confusing.
    You should have a capacitor close the the PICs powerpin.
    Why not throw in a MAX232 or an FTDI?

    USB PIC prog:
    Don't you need a resistor on pin 1, MCLR?
    U2s pin 27, PGC is tied to ground. Should it be?
    U2s pin 28, PGD, is left floating...
    Are K1 & K2 relays? If so, consider EMF diodes.

    Just my thoughts... :)
     
    MaxHeadRoom likes this.
  9. mikejp56

    Thread Starter Member

    Jun 14, 2015
    49
    1
    Hi nerdegutta,
    PIC Experimenter Board:
    1) Yes I forgot a pot connected to +5V and pin 3 for contrast.
    2) The LEDs are labeled as D0-D7, the contacts for them are labeled as LED0-LED7. I will change the labeling of the LEDs to LED0-LED7.
    3) The 0.1uF cap is on the board. It will be added to the schematic.

    USB PIC Prog
    I used the schematic, firmware, and software from Circuits Gallery for USB Pic Prog. I have built 2 of these and they both work well as drawn. The original has a header for configuring as a programmer or for upgrading the firmware via bootloader. I chose to hardwire it as a programmer and leave out the bootloader option. So pins 1,27,and 28 on the '2550 are as shown.
    Yes there should be catch diodes on the relays K1 and K2, and there should also be a ground connection. The schematics will be corrected and uploaded soon.

    Thanks for keeping me honest!
    Regards,
    Mike
     
  10. ISB123

    Well-Known Member

    May 21, 2014
    1,239
    527
    You can use mcp2221 IC to get the USB interface going.
     
  11. mikejp56

    Thread Starter Member

    Jun 14, 2015
    49
    1
    Hi ISB123,
    I don't understand what you mean.
    The PIC18F2550 in the USB Pic Prog schematic is the USB interface. You can write programs in whatever language with whatever compiler you want. Once you have the .hex file, you program the PIC in the ZIF socket with the .hex file and run the program.
    Regards,
    Mike
     
  12. ISB123

    Well-Known Member

    May 21, 2014
    1,239
    527
    Ohh it has built in USB interface so you dont need the IC I said before.
     
  13. mikejp56

    Thread Starter Member

    Jun 14, 2015
    49
    1
    Hi ISB123,
    That is correct.
    Mike
     
  14. dannyf

    Well-Known Member

    Sep 13, 2015
    1,835
    367
    Just plug it into a breadboard.
     
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