serial.c

#include <stdint.h>
#include "uart_irda_cir.h"
#include "soc_AM335x.h"
#include "interrupt.h"
#include "beaglebone.h"
#include "consoleUtils.h"
#include "hw_types.h"

#include "serial.h"

/******************************************************************************
 **              INTERNAL MACRO DEFINITIONS
 ******************************************************************************/
#define BAUD_RATE_115200          (115200)
#define UART_MODULE_INPUT_CLK     (48000000)

/******************************************************************************
 **              INTERNAL FUNCTION PROTOTYPES
 ******************************************************************************/
static void UARTIsr(void);
static void UartInterruptEnable(void);
static void UartBaudRateSet(void);

/******************************************************************************
 **              INTERNAL VARIABLES
 ******************************************************************************/
// Callback function pointer for when we receive a character
static void (*g_rxIsrCallback)(uint8_t) = 0;


/******************************************************************************
 **              FUNCTION DEFINITIONS
 ******************************************************************************/

void Serial_init(void)
{
	/* Configuring the system clocks for UART0 instance. */
	UART0ModuleClkConfig();
	/* Performing the Pin Multiplexing for UART0 instance. */
	UARTPinMuxSetup(0);
	/* Performing a module reset. */
	UARTModuleReset(SOC_UART_0_REGS);
	/* Performing Baud Rate settings. */
	UartBaudRateSet();
	/* Switching to Configuration Mode B. */
	UARTRegConfigModeEnable(SOC_UART_0_REGS, UART_REG_CONFIG_MODE_B);
	/* Programming the Line Characteristics. */
	UARTLineCharacConfig(SOC_UART_0_REGS,
	                     (UART_FRAME_WORD_LENGTH_8 | UART_FRAME_NUM_STB_1),
	                     UART_PARITY_NONE);
	/* Disabling write access to Divisor Latches. */
	UARTDivisorLatchDisable(SOC_UART_0_REGS);
	/* Disabling Break Control. */
	UARTBreakCtl(SOC_UART_0_REGS, UART_BREAK_COND_DISABLE);
	/* Switching to UART16x operating mode. */
	UARTOperatingModeSelect(SOC_UART_0_REGS, UART16x_OPER_MODE);
	/* Select the console type based on compile time check */
	ConsoleUtilsSetType(CONSOLE_UART);
	/* Performing Interrupt configurations. */
	UartInterruptEnable();
}

void Serial_setRxIsrCallback(void (*rxIsrCallback)(uint8_t))
{
	g_rxIsrCallback = rxIsrCallback;
}


/******************************************************************************
 **              INTERNAL FUNCTIONS
 ******************************************************************************/

/*
 ** A wrapper function performing Baud Rate settings.
 */
static void UartBaudRateSet(void)
{
	unsigned int divisorValue = 0;

	/* Computing the Divisor Value. */
	divisorValue = UARTDivisorValCompute(UART_MODULE_INPUT_CLK,
	                                     BAUD_RATE_115200,
	                                     UART16x_OPER_MODE,
	                                     UART_MIR_OVERSAMPLING_RATE_42);

	/* Programming the Divisor Latches. */
	UARTDivisorLatchWrite(SOC_UART_0_REGS, divisorValue);
}

/*
 ** A wrapper function performing Interrupt configurations.
 */
static void UartInterruptEnable(void)
{
	/* Enabling IRQ in CPSR of ARM processor. */
	IntMasterIRQEnable();

	/* Configuring AINTC to receive UART0 interrupts. */
	/* ..Initializing the ARM Interrupt Controller. */
	IntAINTCInit();
	/* ..Registering the Interrupt Service Routine(ISR). */
	IntRegister(SYS_INT_UART0INT, UARTIsr);
	/* ..Setting the priority for the system interrupt in AINTC. */
	IntPrioritySet(SYS_INT_UART0INT, 0, AINTC_HOSTINT_ROUTE_IRQ);
	/* ..Enabling the system interrupt in AINTC. */
	IntSystemEnable(SYS_INT_UART0INT);

	/* Enabling the specified UART interrupts. */
	UARTIntEnable(SOC_UART_0_REGS, (UART_INT_RHR_CTI));
}

/*
 ** Interrupt Service Routine for UART.
 */
static void UARTIsr(void)
{
	unsigned int intId = 0;

	/* Checking the source of UART interrupt. */
	intId = UARTIntIdentityGet(SOC_UART_0_REGS);

	switch (intId) {

	case UART_INTID_RX_THRES_REACH:
		// Call the user's RX function (if any)
		if (g_rxIsrCallback != 0) {
			uint8_t rxByte = UARTCharGetNonBlocking(SOC_UART_0_REGS);
			UARTCharPutNonBlocking(SOC_UART_0_REGS, rxByte);

			g_rxIsrCallback(rxByte);
		} else {
			// Indicate that there's no callback function registered.
			UARTCharPutNonBlocking(SOC_UART_0_REGS, '!');
		}
		break;

	default:
		break;
	}

}