File content as of revision 7:8443cecf62d1:

#ifndef __SERIAL_H__
#define __SERIAL_H__

#include "mbed_globals.h"
#include "interrupts.h"

/*    Simple Serial Managment     *
 * The interrupt handler is :     *
 * SERIAL_INTERRUPT_HANDLER(void) *
 * UART0 : Serial over USB        *
 * UART1 : TX p13, RX p14         *
 * UART2 : TX p28, RX p27         *
 * UART3 : TX p9,  RX p10         */
 
// Serial port (Choose UARTn (0,1,2,3))
#define UART_NUMBER UART0
#define UART_BASE TOKENPASTE2(LPC_,UART_NUMBER)

// Peripheral Clock Selection registers (See 4.7.3 p56)
#define UART0_PCLK_REG (LPC_SC->PCLKSEL0)
#define UART1_PCLK_REG (LPC_SC->PCLKSEL0)
#define UART2_PCLK_REG (LPC_SC->PCLKSEL1)
#define UART3_PCLK_REG (LPC_SC->PCLKSEL1)
#define UART_PCLK_REG  TOKENPASTE2(UART_NUMBER,_PCLK_REG)

#define UART0_PCLK_OFFSET   6
#define UART1_PCLK_OFFSET   8
#define UART2_PCLK_OFFSET  16
#define UART3_PCLK_OFFSET  18
#define UART_PCLK_OFFSET   TOKENPASTE2(UART_NUMBER,_PCLK_OFFSET)

#define UART0_PCLK ((LPC_SC->PCLKSEL0 >>  6) & 0x03)
#define UART1_PCLK ((LPC_SC->PCLKSEL0 >>  8) & 0x03)
#define UART2_PCLK ((LPC_SC->PCLKSEL1 >> 16) & 0x03)
#define UART3_PCLK ((LPC_SC->PCLKSEL1 >> 18) & 0x03)
#define UART_PCLK TOKENPASTE2(UART_NUMBER,_PCLK)

// Pin Function Select register (See 8.5.1-8 p108)
#define UART0RX_PINSEL_REG (LPC_PINCON->PINSEL0)
#define UART1RX_PINSEL_REG (LPC_PINCON->PINSEL1)
#define UART2RX_PINSEL_REG (LPC_PINCON->PINSEL0)
#define UART3RX_PINSEL_REG (LPC_PINCON->PINSEL0)
#define UARTRX_PINSEL_REG  TOKENPASTE2(UART_NUMBER,RX_PINSEL_REG)

#define UART0TX_PINSEL_REG (LPC_PINCON->PINSEL0)
#define UART1TX_PINSEL_REG (LPC_PINCON->PINSEL0)
#define UART2TX_PINSEL_REG (LPC_PINCON->PINSEL0)
#define UART3TX_PINSEL_REG (LPC_PINCON->PINSEL0)
#define UARTTX_PINSEL_REG  TOKENPASTE2(UART_NUMBER,TX_PINSEL_REG)

#define UART0RX_PINSEL_OFFSET   6
#define UART1RX_PINSEL_OFFSET   0
#define UART2RX_PINSEL_OFFSET  22
#define UART3RX_PINSEL_OFFSET   2
#define UARTRX_PINSEL_OFFSET    TOKENPASTE2(UART_NUMBER,RX_PINSEL_OFFSET)

#define UART0TX_PINSEL_OFFSET   4
#define UART1TX_PINSEL_OFFSET  30
#define UART2TX_PINSEL_OFFSET  20
#define UART3TX_PINSEL_OFFSET   0
#define UARTTX_PINSEL_OFFSET    TOKENPASTE2(UART_NUMBER,TX_PINSEL_OFFSET)

#define UART0_PINSEL_VALUE    1UL
#define UART1_PINSEL_VALUE    1UL
#define UART2_PINSEL_VALUE    1UL
#define UART3_PINSEL_VALUE    2UL
#define UART_PINSEL_VALUE     TOKENPASTE2(UART_NUMBER,_PINSEL_VALUE)

// Interrupt handlers
#define SERIAL_INTERRUPT_HANDLER extern "C" void __irq TOKENPASTE2(UART_NUMBER,_IRQHandler)

/** Bits **/
// RBR Interrupt Enable (UnIER, 14.4.4 p302)
#define RBR_INT_BIT 0
// Receiver Data Ready (UnLSR, 14.4.8 p306)
#define RDR_BIT 0
// Transmitter Holding Register Empty (UnLSR, 14.4.8 p306)
#define THRE_BIT 5
// RBR Interrupt Enable (UnIER, 14.4.4 p302)
#define SERIAL_INT_RX 1
// THRE Interrupt Enable (UnIER, 14.4.4 p302)
#define SERIAL_INT_TX 2
// Divisor Latch Access Bit (UnLCR, 14.4.7 p306)
#define DLA_BIT 7
// Power Control for Peripherals (PCONP, 4.8.7.1 p63)
#define UART0_PCONP_BIT  3
#define UART1_PCONP_BIT  4
#define UART2_PCONP_BIT 24
#define UART3_PCONP_BIT 25

/** Macros **/
#define SERIAL_PUTCHAR(c)               while (GET_BIT_VALUE(UART_BASE->LSR, THRE_BIT) == 0); \
                                        UART_BASE->THR = c;

#define SERIAL_DATA_TO_READ()           (GET_BIT_VALUE(UART_BASE->LSR, RDR_BIT) == 1)

#define SERIAL_GETCHAR()                (UART_BASE->RBR)

// Enable interrupt for RX or TX (SERIAL_INT_RX and SERIAL_INT_TX)
#define SERIAL_ENABLE_INTERRUPT(value)  UART_BASE->IER = value; \
                                        ENABLE_INTERRUPT(TOKENPASTE2(UART_NUMBER,_IRQn));

inline void SERIAL_INIT()
{
    // Enable UARTn
    SET_BIT_VALUE(LPC_SC->PCONP, TOKENPASTE2(UART_NUMBER,_PCONP_BIT) , 1);
    // Enable FIFO and reset RX/TX FIFO (See 14.4.6 p305)
    UART_BASE->FCR = 0x07;
    // 8-bits, No Parity, 1 stop bit (See 14.4.7 p306)
    UART_BASE->LCR = 0x03;
    // Set CCLK as Peripheral Clock for UART (96MHz with mbed library)
    UART_PCLK_REG = UART_PCLK_REG & ~(3UL << UART_PCLK_OFFSET) | (1UL << UART_PCLK_OFFSET);
    // Define Pin's functions as UART
    UARTRX_PINSEL_REG = UARTRX_PINSEL_REG & ~(3UL << UARTRX_PINSEL_OFFSET) | (UART_PINSEL_VALUE << UARTRX_PINSEL_OFFSET);
    UARTTX_PINSEL_REG = UARTTX_PINSEL_REG & ~(3UL << UARTTX_PINSEL_OFFSET) | (UART_PINSEL_VALUE << UARTTX_PINSEL_OFFSET);
}

// See 14.4.5 p303
inline int SERIAL_CHECK_INTERRUPT(void) {
    uint32_t serialStatus = UART_BASE->IIR;

    if (serialStatus & 1) // IntStatus, 1 = No Interrupt is pending.
        return 0;

    serialStatus = (serialStatus >> 1) & 0x3; // IntId, 2 = More than threshold data to read, 6 = Some caracters to read
    if (serialStatus != 2 && serialStatus != 6)
        return 0;

    return 1;
}

inline void SERIAL_SETBAUD(unsigned int baud) {
    // Peripheral Clock Selection register bit values (See Table 42, p57)
    static int divisors[4] = { 4, 1, 2, 8 };
    
    uint16_t divisorValue = ((SystemCoreClock / 16 / baud) * divisors[UART_PCLK]);
    
    UART_BASE->LCR |= (1 << DLA_BIT);
    UART_BASE->DLM = (uint8_t) (divisorValue >> 8);
    UART_BASE->DLL = (uint8_t)  divisorValue;
    UART_BASE->LCR &= ~(1 << DLA_BIT);
}

#endif