Hello Chen, > There are 4k7 pull-down resistor between RB6/RB7 and GND. > = > Go to http://www.microchip.com/icd2 and download the > Using MPLAB(R) ICD 2 Poster and you will know that. yes, I've already seen that. Some programmers (like Presto, from = Asix) disconnects the its circuit from RB6 and RB7 when iddle. That way = you can use those pins (say, for detecting key presses) without the need = to disconnect the programmer. ICD2 seens to let more than just a pull-down connected as even when = using the port as output (to light a LED, for example) it's held down = while ICD2 is connected. > The same for the new red button PICkit 2. It is said that > these two resistors are useful for debugging. Ok, but it's not necessary when using it just as a programmer and = it's idle. There's an interesting project called Potyo2 = (http://www.icd2clone.com/wiki/Main_Page) wich uses a 74HC4066 to = disconnect those pins when idle. There's some other ICD2 clones out there, some very cheap on eBay, = but I don't know if they do it or not. Best regards, Brusque -- = --------------------------------------------------------------------- Edson Brusque Stagetronics Eletro Eletr=F4nicos Ltda Research and Development Blumenau - SC - Brazil http://www.ryan.com.br/netiqueta.htm www.citronics.com.br --------------------------------------------------------------------- -- = http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist