Provided are an application processor and a semiconductor system including the same. The semiconductor system includes the application processor, which may include a first register value and of which an operation is controlled by the first register value. The semiconductor system also includes a semiconductor device, which may include a second register value and of which an operation is controlled by the second register value, and a memory storing a third register value that is a copy of the first register value and a fourth register value that is a copy of the second register value. If the stored third register value is changed, the changed third register value is mapped onto the first register value of the processor, and if the fourth register value is changed, the changed fourth register value is mapped onto the second register value.