Can someone tell me how USB programmers like Pickit 2 work. I mean they are only powered from the USB port +5v. How do they put the pic in prog.mode 13v on MCLR ?
Can someone tell me how USB programmers like Pickit 2 work. I mean they are only powered from the USB port +5v. How do they put the pic in prog.mode 13v on MCLR ?
They have a processor on board which does the actual programming, the USB is used to just transfer the data. The Vpp voltage is generated using a switch-mode system, usually direct from the on-board PIC.
Check the PICKIT2 circuit, or Bill's Junebug clone.