Getting information about the hardware

1. Looking at the BCM2837 ARM Peripherals manual, we figure out how to use the Mini_UART interrupt.

Steps to setup the receive interrupts

1. Page 12. AUX_MU_IER_REG to enable receive interrupts. Changes in the "uart_init ( void )"
2. Enable uart interrupt on "enable_interrupt_controller()".
3. Page 9. Look at AUX_IRQ Bit 0 for mini UART interrupt pending in "handle_irq(void)".
4. Create interrupt handler: handle_uart_irq().