Low cost ICSP PIC-programmer using PIC16F648A

Galvanic from PC isolated PIC programmer

The Wisp648 from www.voti.nl is an In Circuit Serial Programmer to program a flash PIC which mostly can stay in your circuit.
No irritating doings like pulling the PIC out of the PCB, place it in the programmer, programming it, pull it out the programmer and place it back in the PCB, over and over again, it can stay in the circuit on your breadboard or PCB while programming the PIC.
It becomes risky when the PIC is connected direct to 230V main, like the wireless controlled (and trafo-less!) dimmer from this site, then it’s better to program the PIC separate from the circuit.

USB-serial adapter

Another solution to protect your PC is to isolate the Wisp648 programmer galvanic from the PC or to build the Galva-Wisp, that’s the Wisp628 but galvanic separated by two dual-optocouplers.
The Galva-Wisp is expanded with a green power on LED, a red program LED and a pushbutton for the possibility to reset the programmed PIC manual.
By the way, the manual reset is only possible when MCLR is enabled. (CONFIG MCLRE_ON in PIC-Basic (= default))
The difference with Galva-Wisp MARK I is that MARK II has no MAX232 chip anymore.

The Galva-Wisp takes his power from the target PIC circuit (where the PIC stays which has to be programmed) (5V/20mA) and the RS232 COM-port (+/- 9V…12V).
The PIC which must be programmed can stay on his own PCB (or breadboard) while programming it, see the pictures underneath.

To connect the programmer with the PIC which must
be programmed you can do it with wires but it is more easy
when using a DIL-clip.
Programming the PIC is then also possible when the PIC is
already soldered into a PCB (see pictures above this one).

The cable on the DIL-clip should not be longer than 1 metre, recommended is a cable with a shield on each wire (see picture).

All by Galva-Wisp / Wisp648 programmable PIC devices in numeric order
PIC’s programmable by Galva-Wisp / Wisp648 (a selection)
Review connections some PIC devices
More info about In Circuit Serial Programming (ICSP)
Conrad have a DIL-clip in his assortment
PCB 130101 Etch it by yourself (31mm x 53mm) (Etch manual on the Dutch section)
IC1 PIC16F648A – Download the HEX file on the bottom of this page
IC2,IC3 PC827 (of LTV827) (dual optocouplers)
LED1,LED2 Green and red LED, Ø3mm, low current type
T1 BC547 NPN transistor
T2 TIP120 NPN darlington transistor (see text)
D1,D2,D3,D4 BAT85 Schottky diode (if not available, then 1N4148)
D5 SB140 Schottky diode (or SB130, or 1N5819)
X1 Crystal 20MHz
R1,R2,R9…R12 1k
R3…R8 47Ω
R13 2k2
C1 1000µF / 6,3V or 10V (radial) (see text)
C2 100n, axial (comes under IC1, in the IC socket)
C3,C4 1µF (tantalium)
C5 22µF
C6,C7 22pF
S1 Reset push button (may left away)
Conn1 15-pole sub-D connector, male
Conn2 9-pole sub-D connector, female
IC-socket 18-pins, own choice


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About The Author

Ibrar Ayyub

I am an experienced technical writer holding a Master's degree in computer science from BZU Multan, Pakistan University. With a background spanning various industries, particularly in home automation and engineering, I have honed my skills in crafting clear and concise content. Proficient in leveraging infographics and diagrams, I strive to simplify complex concepts for readers. My strength lies in thorough research and presenting information in a structured and logical format.

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