> I'm working on a design for a PIC18F452 based board that can be > programmed in the field, by folk who do not have the standard > Microchip > tools, such as a Picstart+ or an ICD-2. I don't wish to use a > bootloader, since this would require the user to have access to a > pre-loaded PIC, so I'm looking around for a simple circuit to > build into > my PCB to enable a blank PIC to be loaded with a .HEX file or similar. So you want a programmer build into your circuit. Depending on the interface (serial, parallel, USB) and the programming type (HVP, LVP) there are various options. Just look around for DIY programmers. Maybe you should reconsider your aversion to bootloaders. Bootloader hardware can be very simple (see my ZPL) and the users have to buy their PICs somewhere, so why not from you (or me :)) pre-loaded with a bootloader? Wouter van Ooijen -- ------------------------------------------- Van Ooijen Technische Informatica: www.voti.nl consultancy, development, PICmicro products -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu