I work with PIC microcontrollers quite a bit and have never understood why Vpp (programming voltage) is higher than the max supply voltage that powers the PIC?
Electronic – Why is PIC Programming Voltage Higher Than Vsupply
picprogramming
Related Topic
- Electronic – Programming a PIC with a PIC
- Electronic – Why we use #pragma configs in PIC controllers
- Electronic – Programming PIC with PICkit3 – do I need enabled MCLR
- Electrical – How to connect a dsPic30f2010 to pickit3 icsp
- Electronic – PIC Programming commands
- Electronic – Capacitors in a Boost Convertor
- Electronic – Returning to PIC programming after a decade…hitting a brick wall
Best Answer
In older (EPROM) PICs the higher voltage was used directly to power the internal EPROM programming hardware. In the newer (FLASH) PICs the FLASH programming voltage is derived internally, and the Vpp is used only to enable the programming mode. Then why use a high voltage at all? This way you can use a single pin for multiple function, so you don't loose a pin exclusively for enabling programing. Note that a lot of PICs have an alternate method of enabling progamming (called LVP), which does dedicate a pin to enabling programming mode. But this can be disabled (so the pin can be used for its normal I/O purpose) by using HVP. Other modern PICs use a 'magical sequence' that must be clocked 'into' the reset pin to enable programming.