Diff: targets/TARGET_NXP/TARGET_LPC11U6X/serial_api.c

Revision:

149:156823d33999

Parent:

144:ef7eb2e8f9f7

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_NXP/TARGET_LPC11U6X/serial_api.c	Fri Oct 28 11:17:30 2016 +0100
@@ -0,0 +1,489 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2013 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// math.h required for floating point operations for baud rate calculation
+#include "mbed_assert.h"
+#include <math.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include "serial_api.h"
+#include "cmsis.h"
+#include "pinmap.h"
+
+#if DEVICE_SERIAL
+
+/******************************************************************************
+ * INITIALIZATION
+ ******************************************************************************/
+
+#define UART_NUM      5
+
+// CFG
+#define UART_EN       (0x01<<0)
+
+// CTL
+#define TXBRKEN       (0x01<<1)
+
+// STAT
+#define RXRDY         (0x01<<0)
+#define TXRDY         (0x01<<2)
+#define DELTACTS      (0x01<<5)
+#define RXBRK         (0x01<<10)
+#define DELTARXBRK    (0x01<<11)
+
+static const PinMap PinMap_UART_TX[] = {
+    {P0_19, UART_0, 1},
+    {P1_18, UART_0, 2},
+    {P1_27, UART_0, 2},
+    {P1_8 , UART_1, 2},
+    {P0_14, UART_1, 4},
+    {P1_0 , UART_2, 3},
+    {P1_23, UART_2, 3},
+    {P2_4 , UART_3, 1},
+    {P2_12, UART_4, 1},
+    { NC  , NC    , 0}
+};
+
+static const PinMap PinMap_UART_RX[] = {
+    {P0_18, UART_0, 1},
+    {P1_17, UART_0, 2},
+    {P1_26, UART_0, 2},
+    {P1_2 , UART_1, 3},
+    {P0_13, UART_1, 4},
+    {P0_20, UART_2, 2},
+    {P1_6 , UART_2, 2},
+    {P2_3 , UART_3, 1},
+    {P2_11, UART_4, 1},
+    {NC   , NC    , 0}
+};
+
+static uint32_t serial_irq_ids[UART_NUM] = {0};
+static uart_irq_handler irq_handler;
+
+int stdio_uart_inited = 0;
+serial_t stdio_uart;
+
+void serial_init(serial_t *obj, PinName tx, PinName rx) {
+    int is_stdio_uart = 0;
+    
+    // determine the UART to use
+    UARTName uart_tx = (UARTName)pinmap_peripheral(tx, PinMap_UART_TX);
+    UARTName uart_rx = (UARTName)pinmap_peripheral(rx, PinMap_UART_RX);
+    UARTName uart = (UARTName)pinmap_merge(uart_tx, uart_rx);
+    MBED_ASSERT((int)uart != NC);
+    
+    switch (uart) {
+        case UART_0:
+            obj->index = 0;
+            LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 12);
+            break;
+        case UART_1:
+            obj->index = 1;
+            LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 20);
+            LPC_SYSCON->PRESETCTRL |= (1 << 5);
+            break;
+        case UART_2:
+            obj->index = 2;
+            LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 21);
+            LPC_SYSCON->PRESETCTRL |= (1 << 6);
+            break;
+        case UART_3:
+            obj->index = 3;
+            LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 22);
+            LPC_SYSCON->PRESETCTRL |= (1 << 7);
+            break;
+        case UART_4:
+            obj->index = 4;
+            LPC_SYSCON->SYSAHBCLKCTRL |= (1 << 22);
+            LPC_SYSCON->PRESETCTRL |= (1 << 8);
+            break;
+    }
+
+    if (obj->index == 0)
+        obj->uart = (LPC_USART0_Type *)uart;
+    else
+        obj->mini_uart = (LPC_USART4_Type *)uart;
+    
+    if (obj->index == 0) {
+        // enable fifos and default rx trigger level
+        obj->uart->FCR = 1 << 0  // FIFO Enable - 0 = Disables, 1 = Enabled
+                       | 0 << 1  // Rx Fifo Clear
+                       | 0 << 2  // Tx Fifo Clear
+                       | 0 << 6; // Rx irq trigger level - 0 = 1 char, 1 = 4 chars, 2 = 8 chars, 3 = 14 chars
+        // disable irqs
+        obj->uart->IER = 0 << 0  // Rx Data available irq enable
+                       | 0 << 1  // Tx Fifo empty irq enable
+                       | 0 << 2; // Rx Line Status irq enable
+    }
+    else {
+        // Clear all status bits
+        obj->mini_uart->STAT = (DELTACTS | DELTARXBRK);
+        // Enable UART
+        obj->mini_uart->CFG |= UART_EN;
+    }
+    // set default baud rate and format
+    serial_baud  (obj, 9600);
+    serial_format(obj, 8, ParityNone, 1);
+    
+    // pinout the chosen uart
+    pinmap_pinout(tx, PinMap_UART_TX);
+    pinmap_pinout(rx, PinMap_UART_RX);
+    
+    // set rx/tx pins in PullUp mode
+    if (tx != NC) {
+        pin_mode(tx, PullUp);
+    }
+    if (rx != NC) {
+        pin_mode(rx, PullUp);
+    }
+    
+    is_stdio_uart = (uart == STDIO_UART) ? (1) : (0);
+    
+    if (is_stdio_uart && (obj->index == 0)) {
+        stdio_uart_inited = 1;
+        memcpy(&stdio_uart, obj, sizeof(serial_t));
+    }
+}
+
+void serial_free(serial_t *obj) {
+    serial_irq_ids[obj->index] = 0;
+}
+
+// serial_baud
+// set the baud rate, taking in to account the current SystemFrequency
+void serial_baud(serial_t *obj, int baudrate) {
+    LPC_SYSCON->USART0CLKDIV = 1;
+    LPC_SYSCON->FRGCLKDIV = 1;
+
+    if (obj->index == 0) {
+        uint32_t PCLK = SystemCoreClock;
+        // First we check to see if the basic divide with no DivAddVal/MulVal
+        // ratio gives us an integer result. If it does, we set DivAddVal = 0,
+        // MulVal = 1. Otherwise, we search the valid ratio value range to find
+        // the closest match. This could be more elegant, using search methods
+        // and/or lookup tables, but the brute force method is not that much
+        // slower, and is more maintainable.
+        uint16_t DL = PCLK / (16 * baudrate);
+        
+        uint8_t DivAddVal = 0;
+        uint8_t MulVal = 1;
+        int hit = 0;
+        uint16_t dlv;
+        uint8_t mv, dav;
+        if ((PCLK % (16 * baudrate)) != 0) {     // Checking for zero remainder
+            int err_best = baudrate, b;
+            for (mv = 1; mv < 16 && !hit; mv++)
+            {
+                for (dav = 0; dav < mv; dav++)
+                {
+                    // baudrate = PCLK / (16 * dlv * (1 + (DivAdd / Mul))
+                    // solving for dlv, we get dlv = mul * PCLK / (16 * baudrate * (divadd + mul))
+                    // mul has 4 bits, PCLK has 27 so we have 1 bit headroom which can be used for rounding
+                    // for many values of mul and PCLK we have 2 or more bits of headroom which can be used to improve precision
+                    // note: X / 32 doesn't round correctly. Instead, we use ((X / 16) + 1) / 2 for correct rounding
+
+                    if ((mv * PCLK * 2) & 0x80000000) // 1 bit headroom
+                        dlv = ((((2 * mv * PCLK) / (baudrate * (dav + mv))) / 16) + 1) / 2;
+                    else // 2 bits headroom, use more precision
+                        dlv = ((((4 * mv * PCLK) / (baudrate * (dav + mv))) / 32) + 1) / 2;
+
+                    // datasheet says if DLL==DLM==0, then 1 is used instead since divide by zero is ungood
+                    if (dlv == 0)
+                        dlv = 1;
+
+                    // datasheet says if dav > 0 then DL must be >= 2
+                    if ((dav > 0) && (dlv < 2))
+                        dlv = 2;
+
+                    // integer rearrangement of the baudrate equation (with rounding)
+                    b = ((PCLK * mv / (dlv * (dav + mv) * 8)) + 1) / 2;
+
+                    // check to see how we went
+                    b = abs(b - baudrate);
+                    if (b < err_best)
+                    {
+                        err_best  = b;
+
+                        DL        = dlv;
+                        MulVal    = mv;
+                        DivAddVal = dav;
+
+                        if (b == baudrate)
+                        {
+                            hit = 1;
+                            break;
+                        }
+                    }
+                }
+            }
+        }
+        
+        // set LCR[DLAB] to enable writing to divider registers
+        obj->uart->LCR |= (1 << 7);
+        
+        // set divider values
+        obj->uart->DLM = (DL >> 8) & 0xFF;
+        obj->uart->DLL = (DL >> 0) & 0xFF;
+        obj->uart->FDR = (uint32_t) DivAddVal << 0
+                       | (uint32_t) MulVal    << 4;
+        
+        // clear LCR[DLAB]
+        obj->uart->LCR &= ~(1 << 7);
+    }
+    else {
+        uint32_t UARTSysClk = SystemCoreClock / LPC_SYSCON->FRGCLKDIV;
+        obj->mini_uart->BRG = UARTSysClk / 16 / baudrate - 1;
+        
+        LPC_SYSCON->UARTFRGDIV = 0xFF;
+        LPC_SYSCON->UARTFRGMULT = ( ((UARTSysClk / 16) * (LPC_SYSCON->UARTFRGDIV + 1)) /
+                                    (baudrate * (obj->mini_uart->BRG + 1))
+                                  ) - (LPC_SYSCON->UARTFRGDIV + 1);
+    }
+}
+
+void serial_format(serial_t *obj, int data_bits, SerialParity parity, int stop_bits) {
+    MBED_ASSERT((stop_bits == 1) || (stop_bits == 2)); // 0: 1 stop bits, 1: 2 stop bits
+
+    stop_bits -= 1;
+
+    if (obj->index == 0) {
+        MBED_ASSERT((data_bits > 4) && (data_bits < 9)); // 0: 5 data bits ... 3: 8 data bits
+        MBED_ASSERT((parity == ParityNone) || (parity == ParityOdd) || (parity == ParityEven) ||
+                    (parity == ParityForced1) || (parity == ParityForced0));
+        data_bits -= 5;
+    
+        int parity_enable, parity_select;
+        switch (parity) {
+            case ParityNone: parity_enable = 0; parity_select = 0; break;
+            case ParityOdd : parity_enable = 1; parity_select = 0; break;
+            case ParityEven: parity_enable = 1; parity_select = 1; break;
+            case ParityForced1: parity_enable = 1; parity_select = 2; break;
+            case ParityForced0: parity_enable = 1; parity_select = 3; break;
+            default:
+                return;
+        }
+        
+        obj->uart->LCR = data_bits       << 0
+                       | stop_bits       << 2
+                       | parity_enable   << 3
+                       | parity_select   << 4;
+    }
+    else {
+        // 0: 7 data bits ... 2: 9 data bits
+        MBED_ASSERT((data_bits > 6) && (data_bits < 10));
+        MBED_ASSERT((parity == ParityNone) || (parity == ParityOdd) || (parity == ParityEven));
+        data_bits -= 7;
+
+        int paritysel;
+        switch (parity) {
+            case ParityNone: paritysel = 0; break;
+            case ParityEven: paritysel = 2; break;
+            case ParityOdd : paritysel = 3; break;
+            default:
+                return;
+        }
+        obj->mini_uart->CFG = (data_bits << 2)
+                            | (paritysel << 4)
+                            | (stop_bits << 6)
+                            | UART_EN;
+    }
+}
+
+/******************************************************************************
+ * INTERRUPTS HANDLING
+ ******************************************************************************/
+static inline void uart_irq(uint32_t iir, uint32_t index) {
+    SerialIrq irq_type;
+    switch (iir) {
+        case 1: irq_type = TxIrq; break;
+        case 2: irq_type = RxIrq; break;
+        default: return;
+    }
+    
+    if (serial_irq_ids[index] != 0)
+        irq_handler(serial_irq_ids[index], irq_type);
+}
+
+void uart0_irq()
+{
+    uart_irq((LPC_USART0->IIR >> 1) & 0x7, 0);
+}
+
+void uart1_irq()
+{
+    if(LPC_USART1->STAT & (1 << 2)){
+        uart_irq(1, 1);
+    }
+    if(LPC_USART1->STAT & (1 << 0)){
+        uart_irq(2, 1);
+    }
+}
+
+void uart2_irq()
+{
+    if(LPC_USART2->STAT & (1 << 2)){
+        uart_irq(1, 2);
+    }
+    if(LPC_USART2->STAT & (1 << 0)){
+        uart_irq(2, 2);
+    }
+}
+
+void uart3_irq()
+{
+    if(LPC_USART3->STAT & (1 << 2)){
+        uart_irq(1, 3);
+    }
+    if(LPC_USART3->STAT & (1 << 0)){
+        uart_irq(2, 3);
+    }
+}
+
+void uart4_irq()
+{
+    if(LPC_USART4->STAT & (1 << 2)){
+        uart_irq(1, 4);
+    }
+    if(LPC_USART4->STAT & (1 << 0)){
+        uart_irq(2, 4);
+    }
+}
+
+void serial_irq_handler(serial_t *obj, uart_irq_handler handler, uint32_t id) {
+    irq_handler = handler;
+    serial_irq_ids[obj->index] = id;
+}
+
+void serial_irq_set(serial_t *obj, SerialIrq irq, uint32_t enable) {
+    IRQn_Type irq_n = (IRQn_Type)0;
+    uint32_t vector = 0;
+    if(obj->index == 0){
+        irq_n = USART0_IRQn;   vector = (uint32_t)&uart0_irq;
+    }
+    else{
+        switch ((int)obj->mini_uart) {
+            case UART_0: irq_n = USART0_IRQn;   vector = (uint32_t)&uart0_irq; break;
+            case UART_1: irq_n = USART1_4_IRQn; vector = (uint32_t)&uart1_irq; break;
+            case UART_2: irq_n = USART2_3_IRQn; vector = (uint32_t)&uart2_irq; break;
+            case UART_3: irq_n = USART2_3_IRQn; vector = (uint32_t)&uart3_irq; break;
+            case UART_4: irq_n = USART1_4_IRQn; vector = (uint32_t)&uart4_irq; break;
+        }
+    }
+    
+    if (enable) {
+        if (obj->index == 0) {
+            obj->uart->IER |= (1 << irq);
+        }
+        else {
+            obj->mini_uart->INTENSET = (1 << ((irq == RxIrq) ? 0 : 2));
+        }
+        NVIC_SetVector(irq_n, vector);
+        NVIC_EnableIRQ(irq_n);
+    } else { // disable
+        int all_disabled = 0;
+        SerialIrq other_irq = (irq == RxIrq) ? (RxIrq) : (TxIrq);
+
+        if (obj->index == 0) {
+            obj->uart->IER &= ~(1 << irq);
+            all_disabled = (obj->uart->IER & (1 << other_irq)) == 0;
+        }
+        else {
+            obj->mini_uart->INTENCLR = (1 << ((irq == RxIrq) ? 0 : 2));
+            all_disabled = (obj->mini_uart->INTENSET) == 0;
+         }
+
+        if (all_disabled)
+            NVIC_DisableIRQ(irq_n);
+    }
+}
+
+/******************************************************************************
+ * READ/WRITE
+ ******************************************************************************/
+int serial_getc(serial_t *obj) {
+    while (!serial_readable(obj));
+    if (obj->index == 0) {
+        return obj->uart->RBR;
+    }
+    else {
+        return obj->mini_uart->RXDAT;
+    }
+}
+
+void serial_putc(serial_t *obj, int c) {
+    while (!serial_writable(obj));
+    if (obj->index == 0) {
+        obj->uart->THR = c;
+    }
+    else {
+        obj->mini_uart->TXDAT = c;
+    }
+}
+
+int serial_readable(serial_t *obj) {
+    if (obj->index == 0) {
+        return obj->uart->LSR & 0x01;
+    }
+    else {
+        return obj->mini_uart->STAT & RXRDY;
+    }
+}
+
+int serial_writable(serial_t *obj) {
+    if (obj->index == 0) {
+        return obj->uart->LSR & 0x20;
+    }
+    else {
+        return obj->mini_uart->STAT & TXRDY;
+    }
+}
+
+void serial_clear(serial_t *obj) {
+    if (obj->index == 0) {
+        obj->uart->FCR = 1 << 1  // rx FIFO reset
+                       | 1 << 2  // tx FIFO reset
+                       | 0 << 6; // interrupt depth
+    }
+    else {
+        obj->mini_uart->STAT = 0;
+    }
+}
+
+void serial_pinout_tx(PinName tx) {
+    pinmap_pinout(tx, PinMap_UART_TX);
+}
+
+void serial_break_set(serial_t *obj) {
+    if (obj->index == 0) {
+        obj->uart->LCR |= (1 << 6);
+    }
+    else {
+        obj->mini_uart->CTL |= TXBRKEN;
+    }
+}
+
+void serial_break_clear(serial_t *obj) {
+    if (obj->index == 0) {
+        obj->uart->LCR &= ~(1 << 6);
+    }
+    else {
+        obj->mini_uart->CTL &= ~TXBRKEN;
+    }
+}
+
+
+#endif