chipkit DP32 - stand-alone circuit

Created Thu, 18 Jul 2013 21:37:30 +0000 by orly_andico

orly_andico

Thu, 18 Jul 2013 21:37:30 +0000

hi all,

just discovered this DP32 which looks like a great midway point between the Atmega-based Arduino's and the Maxkit.

i was interested to learn that the 28-DIP processor on the DP32 can also be bought stand-alone for pretty much the same price as an Atmega328.

a lot of us are still in through-hole circuit land and the idea of having an Atmega328 form factor, through-hole part which is 32-bit and 40Mhz is exciting to say the least.

but is there documentation on how to set up the DP32's processor "stand alone" ?

i notice that Chris has an article here - http://caroper.blogspot.sg/2013/06/this-will-be-home-for-my-pic32mx.html

but that's not a minimal configuration. AFAIK the Atmega328 minimal config is just the crystal and two capacitors...

majenko

Thu, 18 Jul 2013 22:11:06 +0000

All you need is a crystal (8MHz) and 2 load capacitors (~18-22pF), plus decoupling capacitors on the power connections, and a 10µF capacitor between Vcap and Vss (ground).

You also want a 10KΩ resistor betwen MCLR and Vdd.

Programming the bootloader requires a hardware programmer, or you can buy the chip with the bootloader already on it from microchipdirect.com (and other places I suspect).

You can connect a USB cable to the D+ and D- lines, Vss. Vusb must be connected to 3.3V regardless of the chip's voltage for USB to work, so it's best to power the whole chip from 3.3V.

There is more detail in the datasheet: [url]http://ww1.microchip.com/downloads/en/DeviceDoc/61168E.pdf[/url]

orly_andico

Fri, 19 Jul 2013 00:43:06 +0000

That sounds about right.. thanks!

I'm thinking of just getting a chipkit DP32 once the local Farnell has some.. and just buy the processor with the bootloader burned in.

This CPU is really great... approachable for us through-hole wire-wrap heads, but with decent RAM and performance. Now if only it were 5V tolerant... :mrgreen:

les1943

Fri, 19 Jul 2013 07:55:57 +0000

I enjoyed the UNO32 it was a great intro to 32 bit , but I found the Arduino and MPIDE annoying , so I have currently gone back a step to 16bit , 5v, C and MPLAB X , this may be of interest ... [url]http://digital-diy.com/forum/electronics-projects/a-pic24-dev-board-from-microchip-t2781.html[/url]

majenko

Fri, 19 Jul 2013 08:35:08 +0000

If you like the pic24, but don't like the programming environment, and find C confusing ;) there is always the Firewing - PIC24 board, Arduino UNO footprint, Firewing Basic compiler (based on Swordfish for the 8 bit PICs - very similar to VB)...

Which reminds me - I must order some more from Dave, I'm out of stock on them now, sold my last one the other day.

caroper

Fri, 19 Jul 2013 10:55:42 +0000

i notice that Chris has an article here - http://caroper.blogspot.sg/2013/06/this-will-be-home-for-my-pic32mx.html but that's not a minimal configuration. AFAIK the Atmega328 minimal config is just the crystal and two capacitors...

It is pretty much minimal in that everything on the board is needed to use the boot loader. You could eliminate the 2 Power LED's and the ICSP header (if you had a Device with the Bootloader pre installed) but the other 2 LEDs and the Two Buttons are needed by the Bootloader.

The 3V3 Voltage regulator is obviously to step down the 5V from USB, you could use external power and eliminate it, but it is easier to have the supply on board as you have 5V available anyway.

the LDR is just there to test the analogue ports and is redundant, the rest is just decoupling.

As an aside you can drop most 28PIN devices into this circuit, I have tested it with the MX150, the PIC24 and the PIC33. Obviously though only the MX250 has the bootloader, the rest I powered with USB but programmed with the ICSP Header.

Cheers Chris

EmbeddedMan

Fri, 19 Jul 2013 18:04:50 +0000

Note that Microchip sells a PIC32MX250F128B with the chipKIT bootloader already programmed on it for $3.80 here: [url]http://www.microchipdirect.com/ProductSearch.aspx?Keywords=TCHIP-USB-MX250F128B[/url]

*Brian