This programmer uses very few component and I have specifically design it to use very little power when idle. The concept of the design is obtained from a version of "BrokeBenji" design where one can have a look here. It doesn't look like it will work reliably in this raw design. I have added two resistors to the original design and posted it to the Electro-Tech forum here as Yet another PIC parallel port programmer. Later users reported that the programmer actually works.
One user suggested to separate the Vdd and Vpp control signals and it was done in this design. Rather than to use a 78L05 and 78L08 to provide the +5V/programming voltage from AC adaptor or two 9V batteries, I try to design one with a 9V battery and a 3V lithium battery CR2032. The two batteries are in series giving me 12V for the VPP/MCLR line. When the programmer is in idle mode, both VPP and VDD is off so effectively the 78L05 has only its device current and the LED indicator current flowing. There is no other component to "drain" the battery.
From the Microchip datasheet on modern flash PICs, it is mentioned that the VPP voltage is just being use as a control signal rather than power signal consuming milliamperes, thus the use of a CR2032 battery would enable long battery life. One can use a double pole switch to switch out both batteries but I choose to use a SPST switch for its small size. A diode is connected to block any current flowing from the CR2032 to other part of the circuit and I think the overall leakage current when the main switch is OFF will not be measurable.
For the connection to the PIC, I have used a six-pin socket with two ground connections. One is for the power to the pic and the other one will go to the PGM pin of the PIC to pull it LOW.
The programming software used is WinPic800 which proves to be very good and fast becoming my favourest choice. The programmer has been tested on all the PICs I have: 12F675, 16F628A, 16F877, 16F877A, 16F88 and 18F4455.
I have included the settings details for WinPic800 so you can set the software up like mine immediately. Don't forget to email and tell me of your success if you have built one of your own.
