Thursday, June 3, 2010

PIC32 MultiMedia Board (MMB)

You may know MikroElektronika from their big development boards for PIC, AVR and ARM microcontrollers; you may even own one. I have one of those boards too, the EasyPIC4 that measures about 19 by 23 cm. This is pretty big and not something that you would use in a project. You can develop your project on it, but you have to build your own hardware if you want to actually use it in an application.

They also do some smaller boards. One particular interesting one is the PIC32 MultiMedia board (MMB) and I managed to get one to play with. For some reason the PIC32 does not get a lot of attention, but maybe this board will change that? It is about 9 by 12 cm and well thought out. On the solder side it has a 320x240 pixel TFT display with touch screen, a mini joystick, 6 LEDs and a temperature sensor. On the component side live all the other parts: the PIC32, the power supply and connectors. It has a power socket, a 9-pin RS-232 connector, an SD-card connector, a mini-USB male and a full-size USB host connector, a microphone input (mono) and a stereo headphones output. There is also an ICD programming port and there is room for an MRF24J40MA ZigBee module from Microchip. All the connectors are on the two sides (top & bottom) of the board, the left & right edges have each a row of holes for pin headers so that you can piggyback another board in case you need one.

When you power the board (with a USB cable f.i.), it does a slideshow of some nice photographs. That is all that it does, but it is pretty hypnotizing: butterfly, flower, tree, chameleon, city, oh… butterly again.

The CDROM labeled “software” does not contain development tools. It has a large amount of examples and documentation, but not only for this board, but for all the MirkoE boards. As I happen to have an ICD3 pod I decided to reprogram the board with the Mandelbrot demo. Loading the precompiled HEX file into the board was easy once the ICD3 pod was done reconfiguring itself. Manipulating the joystick now starts the Mandelbrot demo. With the joystick you can scroll in four directions and pushing it zooms in. It is reasonably fast.

Loading the example code in MPLAB was a bit more problematic as the example makes use of some libraries that were not where they were supposed to be. However, after a bit of relocating files I managed to compile the Mandelbrot demo.

The demo is actually a Microchip demo and a well informed source told me that the reason for this is that the board was originally designed by Microchip, but was outsourced to MikroElektronika due to a lack of resources at Microchip. I have seen a Microchip movie demo on this board, but I do not have the code yet.

There is also a test program on the CDROM. Loading this will light up all the LEDs and fiddling with the joystick you can skip, pass and fail certain tests.

More demos are available on the web page for this board. They let you play Rubik's cube or listen to Boney M and Freddy Mercury. BTW, make sure that the two jumpers behind the headphones socket are in the "UP" position, i.e. closest to de board edge, otherwise you will not hear anything. (See the manual if in doubt.)

One negative point: when I tried to insert the headphones with a jack of the right (3.5 mm) diameter in the headphones socket, the whole thing came off. Luckily it didn't cause any damage to the parts behind it, but it was clearly a case of bad joints. Before inserting anything, check the joints and resolder if necessary. This is probably also a good idea for the microphone socket.

I have tried most of the other demo's too and they are pretty nice. One demo showing off the Microchip graphics object layer gives a good impression of the possibilities of the graphics library.

Conclusion: if you want to give the PIC32 a go, this is definitely a good starting point. The board is reasonably priced ($150) and you could do some nice things with it. I do not really see why you would want to make an MP3 or MP4 player out of it, but transforming it into a DSO or a logic analyzer would sure be an interesting project. The touchscreen with the graphics library allows for very slick user interfaces.

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