Versatile developement board system design

True, ive used it as a development board. The AtomCNC is a great example. First i made a shield and when it was working i made a full 10x10cm pcb ... with arduino and shield all in one... people just done have the experience to do that so they leave as is and buy a new one.

I think its a great system. The IDE SUCKS with no debugging due to the bootloader being the main source of programming.
If i knew more about AVR i would definitely use my arduinos with AVR studio.

I would love a solution like that with DEBUG support. OMG id pay hundreds for that. But ill settle for a PCB that you can simply plug other PCBs without using external passives like resistors and caps. Everything setup into a modular development system. Sort of a plug and play (or Plug n Code) .

NorthGuy said:

...To me, the best board would be very minimalist, but with a very good set of connectors, so that you can easily connect practically anything without wiring it on the breadboard....

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That's exactly the concept behind the TAP-28 board. There are three 6-pin connectors, for ICSP, UART and I2C/SPI. Each of these connectors is configured the same way with 4 port pins, power and ground. They are available for their specific hardware functions or for general purpose use. It's simple to connect a board with a serial interface or with an SPI interface.

There are four 3-pin connectors. Each has one port pin, power and ground. Two of these may be used as analog inputs or for general purpose use, two can be used as PWM outputs or general purpose use. Each of these 4 port pins has the option of a pull-up or pull-down resistor. These are great for connecting an analog sensor, a One-Wire device or a servo.

Finally, on the board are 4 LEDs and two switches that may be used as a user interface, status indication or other purposes. There may be included or removed from the circuit by solder jumpers. Note that vertical or right angle LEDs and switches may be used; right-angle components allow them to be accessible if the board is mounted in a enclosure.

Important is what's not on this board. This board can handle a wide range of 28-pin PICs. A regulated 5 volt supply is easy to come by in the form of a regulated wall wart. If you want to use battery power, a couple AA batteries and an appropriate micro and you're in business. No seven-segment or matrix display, because these won't be used in the typical application. If more accessories are needed, the I2C/SPI is probably an easy solution.

Things that are there are low-cost parts that are part of almost any application and the connectivity to work in real-world situations.

My stock of TAP-28 boards is almost depleted. I haven't decided if I'll make another large batch since the motivation of affordable boards no longer applies.

How much is that board? It looks nice. If you can make something similar with sip headers and the biggest pic in that family. Not pin wise but flash/ram size (I think the 2550 is the same as 4550 but pin size) so thats spot on. Add real usb not just for power on uart. It would be perfect.

Almost all of the 28-pin PIC18F-series have the same pin out and can be used on this board.

I've been thinking about creating a USB version. Two possibilities are to use the 18f2550 or one of the newer 28-pin USB devices or the add an 18F14k50 with USB CDC code (looks like a serial device). Haven't decided which makes the most sense yet.

Very nice board. The connectors with a lock is perhaps not the best choice. For example, PICKit3 will problably not fit onto the ICSP connector unless you cut the lock off. DIP switches or pins for jumpers would be nice to disconnect LEDs.

I always use a short cable with my PICkit 2. Plugging the PICkit directly into a board never works that well for be.

PICkit Hints

Cool.. dont use the 14k50 I have like 10. You can not debug with out special adapter pcb

Id buy 4 of those cables if you want to sell

AtomSoft said:

A dev board is still useful now. Not so say your wrong 3v0 but i still use a couple microchip dev boards.

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To a much lesser degree then in the past.

When I do a design I want to pick which and how IO is used. A dev board that lets you do that is going to be a bother to work with. May as well go right to a PCB ---> IMHO <----

I understand. We all have our own opinions. Im not sure if you made a mistake tho... that comment seems wrong... If the dev board lets you use the pins you want for what you want how is it a bother?

3v0 said:

When I do a design I want to pick which and how IO is used.

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That is because there's no easy way/tool to re-assign pins once the program is written.

AtomSoft said:

Id buy 4 of those cables if you want to sell

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How about fifty cents a piece? Elecrow has them along with lots of other great stuff.

AtomSoft said:

I cant wait to see what you come up with. While this doesnt really apply ... i like small boards with basic needs on them like mines:
https://atomsoft.wordpress.com/2014/04/06/pic18f4xj5x-explorer-v2/
But i do plan on making another. Larger. More pins etc. I would love something like MikroE development boards

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That's amazing... Your board almost looks exactly like the board I whipped up for my pile of 47J53's I had laying around awhile back. Had 25 of them made. Just enough pieces/parts on there to get the PIC actually running, power, caps, pullups, couple buttons, etc. Mine was a bit wider and I broke out some pins on the ends, but nonetheless, made it a helluva lot easier to play with the J53's when I wanted to.

ALL good points.
Make some money == no
An inexpensive development board system == yes
versatility == yes
requires several additional boards aka shields, to be able to use ==no
resent design has only two boards that cover 18, 28, 40pin chips as well as one ADRUNIO. Contemplating adding in socket space for 8 pin chips?
The system is user supplied parts to assemble onto pcboards.
Look at your work bench, how many shields and boards do you have for leds, keyboards, push-buttons etc. I am wanting to cut down on this number even if its just for my use. I love using the TAP28 as it saves me time and parts from repeating soldering sockets, caps, resistors etc to a breadboard every time I want to try something different. I have 3 shields, one for LCD, one for LED matrix and one with several leds and push-buttons. Add to this several boards that just require jumpers but hardly ever use.