Post by thread:[PIC]: FPP software

Hi, I'm looking for help understanding the functions available with David Tait's FPP software, for use with a homebrew programmer. My aim is to ICP a PIC and leave the programmer attached while testing, virtually regardless of the usage of RB6/RB7 in the real circuit. For this I will need to be able to tri-state the programmer outputs to RB6 & RB7 for normal PIC running. RB7 also needs to go tri-state during program verify phase. In addition I need to be able to raise MCLR pin to Vpp, or allow it to 'float' to Vdd in the real circuit, and AFAICT, I also need to be able to ground MCLR to reset the PIC (or at least FPP needs to, but I could be wrong). The readme for FPP says: OUT -- data from the PC to the PIC (usually RB7) CLK -- clock from the PC to the PIC (usually RB6) VDD -- turn on the PIC +5V supply (not always needed) MCLR -- control the PIC /MCLR pin PGM -- used (with MCLR) to establish programming mode READ -- high when PIC must be read IN -- data from the PIC (RB7 again) to the PC CLK, IN & OUT are straight forward enough. MCLR is the next easiest - obviously it is intended to either pull MCLR pin low, or allow it to go high (even to 12V if this is sole control of Vpp). The Stop/Run button will toggle MCLR, but you wouldn't want to run with 12V on the MCLR pin, so I guess this is where PGM comes in. But how exactly? Does it stay on throughout program & verify? VDD seems simple enough, but again is it stable throughout, or switching off between read and verify phases? READ: now I am really hoping I can use this to tri-state the connection to RB7. Otherwise what could it be for? It would help a lot to see the order of the above signals through a whole program, verify & reset sequence - then I could see how best to use them for my programmer. I already have a working circuit using just CLK, IN, OUT & MCLR, with manually switched 12V supply. It's not really good enough as a portable ICP though because of the restrictions on the use of RB6/RB7 in the real circuit. I.e. without tri-stating, the programmer needs to have source impedance to allow the real circuit to run with it still connected, but then the real circuit loads can interfere with programming. Can I do this with FPP? It's the most flexible programmer software I have found yet. -- http://www.piclist.com hint: To leave the PICList spam_OUTpiclist-unsubscribe-requestTakeThisOuTmitvma.mit.edu