SparkFun Forums

[buriedcode]

Hi,

I've posted this in a couple of forums, and after reading lots of posts I thought it would be a good idea to ask here, you guys seem quite passionate about electronics

After playing with PIC's for over a year, using a cheapo DIY uJDM programmer, I've decided to make my own PIC dev board using the 877A as the chip (its got pretty much everything I need, peripheral's wise). Although the boards on SF are nice and cheap, I always try to build my own stuff, as its good practice for PCB design, plus I get to completely customize it.

So, really, I'm asking what people think makes a good dev board? The stuff that'll definately be on it is: Power supply, ICSP header, RS232 (with max232) standard headers for every port, versitile clock (Xtal/RC), LED bargraph.. Optional extras: LCD header, rotary encoder, headers for SPI/I2C, UART, PWM etc..

Obviously I could make it as complicated as I wanted, and its down to what I want to use it for, but I could always make 'add-on boards' with the same pinout as the headers. Do you think it would be a good idea to also have every I/O along a female header strip, for easy wire connection to breadboard? I'm incredibly indecisive, but I don't want to get a PCB made up only to find I've left something out thats handy.

Ultimately, I'm fed up of plugging/unplugging chips, removing wires from I/O's when using ICSP, I would like to be lazy and program the PIC simply using the PC, making prototyping any app a lot quicker.

Sorry for such a vague question, any comments, advice, experiences are welcome,

BuriedCode.

[reklipz]

A reset button. from MCLR to ground.

[buriedcode]

A reset button. from MCLR to ground.

Yep, I'm also isolating the VDD from the VPP voltage with a diode, but hopefully, i won't need that much, hoping to use boot-loading instead, seems far easier. thanks for your input,

BuriedCode.

[reklipz]

A diode is unecessary, although not a bad idea, so long as the pull up resistor from MCLR to Vdd is >= 10K. (right?!)

[buriedcode]

Hi again,

The diode is merely a protection measure, I always find, when designing a PCB, its best to add something 'just in case' as any modifications to the circuit, on a PCB can be tricky.

However, I am comfident that I have everything the PIC needs, including said reset circuit, power, clock, ICSP, header etc..

I was more interested in 'optional extra's' that people would like to see on a PIC dev board to make it more versatile and useful. The basic outline is whats mentioned above, with standard headers for every port, allowing access to every I/O. I'm also toying with the idea of having things like 'LCD header' which would be fairly simply to add on, only requires one pot and would allow quick debugging of a prog (without using an ICD).

After much research, PIC dev boards seem to be either very basic (still very useful) or overly complicated and restrictive (too many beells and whistles and not access to all I/O's). My DIY approach will hopefully yeild something inbetween, at a lower cost. I would post an Eagle3D view of the layout, but I'm not sure whether to post *.jpg's here.

Thankyou,

BuriedCode.