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I had previously used the Adafruit TFT display using my library (ported from the Adafruit Arduino library). I decided to optimize the library to improve drawing speed. The same display I use comes with a 4-wire resistive touch-screen as well. I decided to write a simple library for the touch-screen and give Protothreads a try. To incorporate all this, I thought it would be cool if I used these to make a simple game. Tic-tac-toe came to mind as a fun little demo. I'm sure everyone's familiar with the game so I won't explain the rules there. The touch-screen is simply two resistive sheets placed on top of each other on top of the TFT screen. When it is pressed down at a given place, the two sheets make contact and a voltage divider is formed. Using the IO's and the ADC, this voltage is read in the X and Y directions to register a touch. Here is a very good pictorial depiction of the resistive touch screen (taken from the Atmel AVR341 document ): So in order to read the to...

I recently got a few pieces of the MCP4822 DAC. You can check out the datasheet here: http://ww1.microchip.com/downloads/en/DeviceDoc/22249A.pdf I found them to be neat little devices. In a small 8-pin PDIP package, the MCP4822 comes with 2 12-bit DACs, which you can easily configure over SPI. This was a great opportunity to get a simple PIC32 SPI application going. I worked on this today to see how fast I can get the DAC output going. Here's the pinout of the MCP4822: Fig. 1 - MCP4822 pinout (taken from datasheet) The MCP4822 can be supplied a voltage in the range of 2.7V to 5.5V. Since I use 3.3V for my PIC32, I used the same 3.3V supply for the VDD for the MCP4822. Pin 5 is the active low signal LDAC that is used to synchronize the two DAC channels. When this pin is brought low, the data in the DAC's input register is copied to the output and both outputs are updated at the same time. I just had this tied to ground. VoutA and VoutB are the two output pins. The other pins are...