AT32UC3A3256S_1 Datasheet, PDF (391/961 Pages) ATMEL Corporation – AVR32 32-Bit Microcontroller

AT32UC3A3
21.7 Programming Examples
21.7.1 8-bit LED-Chaser
// Set R0 to GPIO base address
mov R0, LO(AVR32_GPIO_ADDRESS)
orh R0, HI(AVR32_GPIO_ADDRESS)
// Enable GPIO control of pin 0-8
mov R1, 0xFF
st.w R0[AVR32_GPIO_GPERS], R1
// Set initial value of port
mov R2, 0x01
st.w R0[AVR32_GPIO_OVRS], R2
// Set up toggle value. Two pins are toggled
// in each round. The bit that is currently set,
// and the next bit to be set.
mov R2, 0x0303
orh R2, 0x0303
loop:
// Only change 8 LSB
mov R3, 0x00FF
and R3, R2
st.w R0[AVR32_GPIO_OVRT], R3
rol R2
rcall delay
rjmp loop
It is assumed in this example that a subroutine "delay" exists that returns after a given time.
21.7.2
Configuration of USART pins
The example below shows how to configure a peripheral module to control I/O pins. It assumed
in this example that the USART receive pin (RXD) is connected to PC16 and that the USART
transmit pin (TXD) is connected to PC17. For both pins, the USART is peripheral B. In this
example, the state of the GPIO registers is assumed to be unknown. The two USART pins are
therefore first set to be controlled by the GPIO with output drivers disabled. The pins can then be
assured to be tri-stated while changing the Peripheral Mux Registers.
// Set up pointer to GPIO, PORTC
mov R0, LO(AVR32_GPIO_ADDRESS + PORTC_OFFSET)
orh R0, HI(AVR32_GPIO_ADDRESS + PORTC_OFFSET)
// Disable output drivers
32072A–AVR32–03/09
391