See the top level README for information on where to find documentation for the raspberry pi and the ARM processor inside. Also find information on how to load and run these programs. This example is for the pi2, see other directories for other flavors of raspberry pi. This example switches back to SVC mode from HYP mode. This example uses the free running ARM timer, not the 64 bit system timer as in blinker02 but the so called ARM timer. In free running mode which is a little different from blinker04 which uses the timer mode. The system clock appears to come up at 250MHz as documented. Divide that by 250 to get 1Mhz on this free running ARM timer. Then count to four million ticks between LED state changes and the led will change state every four seconds. Count to 20 million, 20 seconds.