Constants

GPIO

Adresses

• GPIO_BASE: The base address of the GPIO registers
• GPSET0: The Base address for setting pin outputs
• GPCLR0: The Base address for clearing pin outputs

Pins

• LED_ACT: Alias for LED_OK
• LED_OK: The pin controlling the OK LED
• LED_PWR: The pin controlling the PWR LED
• GPIO_MAX_PIN: The highest pin number

Other

• GPIO_HIGH: The value to switch on the pin (1 on B+, 0 on B)
• GPIO_LOW: The value to switch off the pin (0 on B+, 1 on B)
• GPIO_IN: The value for setting a pin to input mode (000)
• GPIO_OUT: The value for setting a pin to output mode (001)

System Timer

• ST_BASE: System Timer base address
• ST_CS: System Timer Control/Status (=ST_BASE)
• ST_CL: System Timer Counter (also ST_CL0, lower bits)
• ST_CL1: Counter, higher bits
• ST_Cn,: System Timer Compare n (n is 0 to 3)