540P is a special scan rate and shows 60 full frames per second.
540P does not exist as a video system scan rate within the industry. The reason that it does exist and we use it is because of 1080I displays. If you are scaling standard definition signals to a 1080I native scan rate then this is what you would set the scaler for, 540P. The reason is 540P is progressive and by using progressive you can remove interlace artifacts from the image. The speed of the scan rate is the same making 1080I and 540P directly interchangeable and the display does not know the difference. Note that 540 is half of 1080. For more info check progressive.
For more information go to, Scan rate.