I am trying to setup an Adafruit Wave shield on my Arduino Mega. It uses the SPI digital pins 50, 51, 52, and 53 to communicate with the SD card on board. I have not been able to get it to work, so I thought I would make sure my Arduino pins were working.
So, I ran "blink.pde" on digital pins 50, 51, 52, and 53 and they were not blinking my LED properly. So, I hooked up a multimeter and those four pins are acting strange. Two of them stayed at a value of 4.3 V even though they were supposed to "blink" between 0V and 5V. And, the other two jumped between 1.5V and 3.5V each second, instead of 0V and 5V. I checked all other digital pins and they "blink" nicely between 0V and 4.5V each second.
Long story short... Are the SPI digital pins supposed to output the same voltages as the other digital pins when set HIGH and LOW? If so, should I assume my MEGA is broken (I just bought it)?