I am making a programmer using an Arduino using SPI and SD libraries . I need a command to delete the previous sketch from the target microcontroller but I cant find something on the arduino IDE . Do you know any such command ?
I need a command to delete the previous sketch from the target microcontroller
Why? The new program overwrites the old one when uploaded.
Indeed why ?
And if you erase the Flash before uploading a sketch, the bootloader will be erased.
Avrdude has options for this sort of thing (check the reference) but those are used by the PC when connected to a ISP programmer.
And when all else fails, READ THE DATASHEET. Special attention to chapters 30 and 31.