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Wisp648
© VOTI – Wouter van Ooijen – 2007, 2008, 2009, 2010
last modified 30-MAY-2010
Content
Introduction 1
In-circuit programming 1
Programming details 3
Power 4
Serial pass-through 5
Firmware upgrading 6
Circuit description 7
Kit construction 8
Troubleshooting 13
Connector pin assignments 13
Connecting a target chip 16
FAQ 17
PCB 1.05 bug 19
Abbreviations and acronyms 21
Document history 22
Introduction
Wisp648 is a serial port in-circuit programmer for Microchip FLASH PICmicro microcontrollers.
The list of target PICs that are supported changes too often to include here, check the Wisp648
page at http://www.voti.nl/wisp648 for an up-to-date list.
In-circuit programming
In-circuit programming (often abbreviated as ICP or ICSP) implies that you program your target
chip while it is in its target circuit. There is no need to extract the chip from its circuit, put it in a
programmer, and put it back in the circuit after programming. Instead you make a connection (a
few wires) between the programmer and the target chip, and you can program it without even
touching the circuit.
To make in-circuit programming possible the target circuit must comply with some rules. The
details are explained in the Programming details section (p 3), but the summary is stated in the
table below. When a resistor is mentioned the stated value is a minimum (higher is OK), and any
circuit is OK that has at least the indicated impedance (for instance: an UL2803 has an input
impedance of at least 2k7, so it can be connected directly to PGC, PGD or PGM pins, which
require a minimum impedance of 1k). Pin 7 and 8 (RxD and TxD) are needed only when the Serial
pass-through (p. 5) is used. The colors correspond to the wires supplied with the Wisp648 kit (but
for readability grey is used in the table instead of black).
