On Mar 27, 5:46 pm, mattschinkel <[email protected]> wrote: > I have changed my ICSP schematic many times to try to suit others. No > matter what I do, someone will not be happy. As you can see, nobody > can agree one one schematic and I am still having trouble! > > The schematics from Microchip do not show a reset button, I think a > reset button is useful. If there is no reset button, you will need to > reset your circuit by disconnecting the power. Yes, there are other > ways of resetting your circuit, but some users may not know that. > > Mike, thank you for your schematic which may be most correct, but I am > looking for a simple/cheap schematic. At least yours had a reset > button unlike all others :) > > I think the fault here is not the schematic, it is the programmer. > Some programmers have not been created "to microchip standard", such > as Wisp628 that needs VDD to power it's self. > > Can someone please show me a ICSP schematic with a reset button that > is to Microchip standards that will work on PIC Kit 2? > > Matt. The circuit image I edited and upload will work perfect with PIC kit 2 and Wisp626. The only component over 1 or 2 c is the 1N58xx series Shottky D3. That can be replaced with a Jumper. In most cases the jumper can be left in. If the programmer has it's own VDD power take the jumper out to be sure.
See the boards on this page: http://www.dhmicro.com/product.html (scroll down to) RapidNNiXL Series PIC Prototyping Boards They have VDD jumper so only PIC is powered from ICSP if desired. Some have an RB3/RB4 jumper for disable or using LVP via PGM (last pin on ICSP marked AUX on some schematics). 16F877A needs pull down on LVP PGM pin to do HVP. Here is my programmer http://www.techtir.ie/forums/showthread.php?t=1751 I use it with Velleman K8076 "PIC prog 2009" software (free download) now rather than ICProg. It's kind of "JDM" compatible. It can be powered from Target or separate 5V supply. The Diode (D3) allows Target powered programmers or Self Powered Programmers automatically, and isolates the PSU or the rest of circuit. Some boards it may be inconvenient to power them when programming, but the rest of the circuit may take more power than self powered or USB powered programmer can supply, so in that case a D3 or a Jumper is good. I'm using a 1N5818 for USB slave and/or "rest of circuit" isolation from ICSP/PIC VDD pins. It's not as good as I spec for a new design. About 280mV at 30mA current, 300mV @ 50mA. However I got a load very cheap (about 2c each) and the circuits do work. 150mV drop is more ideal. But it depends on what chips you have. PIC of course is very tolerant. http://www.datasheetcatalog.com/datasheets_pdf/1/N/5/8/1N5818.shtml on datasheet they claim about 140mV at 30 mA :D! -- You received this message because you are subscribed to the Google Groups "jallib" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/jallib?hl=en.
