Project Updates for 10/11/2010

The last couple days I've been working on the servo replacement board. I've been using the new ICD for programming the chip and it's been working well. Unfortunately, with the PIC12F683 chip, using the ICD2 for debugging purposes requires a debug header, which is a small board that interfaces between the chip and the ICD. In order to get the PIC so small, they had to remove some functionality such as the debug circuitry and the header basically functions as the debug circuitry they removed from the chip. Additionally, with so few pins hooking up an LCD display is impractical, although I found circuit that turns a standard HD44780 LCD in to a serial LCD. However, it turns out I didn't need it since I was able to get each aspect of the chip working and tested through a bicolor LED. I was able to reuse the code I created for reading PPM signals in the chip, but due to the chip running at 8MHz rather than 32MHz, I had to set the timer prescaler to a quarter of the value to get the same numbers. At this point, I need to build a simple h-bridge (just enough to turn the motor a little), test out the functionality of the h-bridge, and assemble the pieces of code I have working and then it should be ready to go onto a circuit board. I've located the SMD components along with their datasheets that I need for an H-bridge (that's the only way I'll fit it into a micro servo), and board design will probably happen in parallel to finishing the test circuit.

Posted in Old Posts 11 Oct 2010