Evaluation board for the chips 18F4550 (USB) and 16F877A
The design is essentially a double evaluation board for the chips 18F4550 and 16F877A. It contains also a MAX232A serial module having two transmitters and two receivers with the ability to connect either to 4550 or 877 microcontroller. Each microcontroller port ends up to a pin header in order to give interconnection capabilities to the board for future experiments. The PICs programming can be achieved through the two ICSP connectors. Each ICSP gives access to PGData PGClock MCLR and GND microcontroller pins witch are sufficient enough, to program the device by using a simple serial programmer (for example JDM or ProPIC).
The power supply is accomplished by using TI REG104 5V low drop out voltage regulator. The board also has the capability to be powered by the USB +5V power line.
Now for the software part I included a PIC 18F4550 firmware in assembly witch setup the 4550 in order the chip to be enumerated as a USB full speed device with one control (I/O), one isochronous (Out), one bulk (In) and one interrupt pipe (Out). The original code before my modifications belongs to Bradley A. Minch Of Franklin W. Olin College of Engineering and is freely shared at http://forum.microchip.com/tm.aspx?m=89669&mpage=14. The main loop also can drive two led (pull down) connected to RA1 and RC1 pins on and off for function indication.
Update 2006/04/24 Nick says: "I am sending you the corrected gerbers for the previous F876A design with minor modifications around MCLR pin."
Update 2006/06/15 Nick says: "The new dual PIC board is ready and working, thank you and OLIMEX for the boards. As always in my prototypes, a small mistake exists!!! I am sending you the corrected gerber for the bottom layer where the problem is. The problem is easy to be fixed in the old version of the board with the use of one small wire. Just connect the negative pins of C15 and C16 capacitors. Also there is some pictures of the project for you."