PicKit 2 Clone

What is PicKit-2:

Pickit 2 is an USB based vary powerful loader developed by Microchip. Using of PICkit2 is much more comfortable and reliable than that of those "JDM" programmers you can find all over the internet. PICkit2 is a very powerful device, in addition to a PIC-programmer function it can be used as a serial EEPROM programmer or a debugger with certain PICs. Since PICkit2 is a Microchip product they are continuously updating the software and the firmware to support the newer and newer PICs. You can program the entire range of 8 bit MCUs, the 16 bit 24H and DSP series and even the newest 32 bit famliy with PICkit2.

Benefits of PicKit-2:

    • It uses USB port and its belt in +5v to drive and complete the hole job of programming. So no more botheration of external power input. Even modern laptop can use it only needs an USB port available.
    • Because this is a Microchip product, they are developing and updating the internal firmware with open source.
    • Documentations and other files of original PICkit2 are at the manufacturer's site: Microchip PICkit2 site.   

    Modifications done to Clone:

    • I've used USB-B connector on the clone. This type of printer cable is almost available to everyone.
    • Beside the ICSP header, a zif socket is mounted on the PCB with jumper selector for 40 pin and the other small devices. So external EPROM can be programmed.
    • The PICkit2 clone has been designed using only hole-mounted parts. Ready to go function is now available with 2 x 24C512 chips.
    • Finally the MOSFETs are working in the clone instead of bipolar transistors, so minimal additional components are needed.  
    • Still 3.3v Devices can’t be programmed. In next modification ill add it.

    Theory of Operation:
    Just concentrate the schematics. You see all the operations are completed by the PIC18F2550. It maintain communication with the host computer via USB bus, controls the Vpp pump if necessary, switches Vdd and drives the lines to the target circuit.
    Q1, L1, D1 and C1 used as dc-dc Boost converter to control Mclr voltage. R11, R12 are voltage divider to check feedback to check Vpp (Mclr Voltage). Q4 and Q5 with R10 are for switching Vpp to the MCLR/Vpp output. Q6 with R4 gives an active pull-down to MCLR line when it is needed. LED1 (green, with R12) shows that clone is connected to the USB.
     
    Q3 is for switching the Vdd on the output Vdd line. PIC takes vdd feedback from Q2, R13. D2 protects the circuit from external Vdd voltage. Yellow colored LED2 (with its series resistor R15) indicates that Vdd is switched to the output.
    The firmware controls red led (with R17) to indicate different states of operating. Normally it lights during the read and write operations, means "busy" state.

    R1, R2 and R3 are current limiting resistors in series the output lines PGD, PGC and AUX. R5 and R4 ensures the low level at the PGD and PGC lines in certain cases.

    Push button function:
    * Holding the Push button during connecting Pickit2 to the host Pc, triggers the boot loader mode. Normally it is used when downloading new pickit2 firmware to the 18F2550.
    * Another basic function of the switch is, it programs a Pic with last loaded Hex in the host pc’s Pickit-2 software.

    Construction:

    Find the Artwork and Hex here.

    Remember PicKit 2 host application needs Dot Net Framework to run

    Download USB host Application with Dot Net Framework here.

    Download USB host Application without Dot Net Framework here.
    For any other help leave a comment or contact me on email.