Diff: targets/TARGET_Freescale/TARGET_K20XX/serial_api.c

Revision:

0:f269e3021894

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_Freescale/TARGET_K20XX/serial_api.c	Sun Oct 23 15:10:02 2016 +0000
@@ -0,0 +1,301 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2015 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.
+ */
+#include "mbed_assert.h"
+#include "serial_api.h"
+
+#include <string.h>
+
+#include "cmsis.h"
+#include "pinmap.h"
+#include "clk_freqs.h"
+#include "PeripheralPins.h"
+
+#define UART_NUM    3
+
+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) {
+    // 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);
+
+    obj->uart = (UART_Type *)uart;
+    // enable clk
+    switch (uart) {
+        case UART_0: 
+            mcgpllfll_frequency();
+            SIM->SCGC4 |= SIM_SCGC4_UART0_MASK; 
+            break;
+        case UART_1:
+            mcgpllfll_frequency();
+            SIM->SCGC4 |= SIM_SCGC4_UART1_MASK;
+            break;
+        case UART_2:
+            SIM->SCGC4 |= SIM_SCGC4_UART2_MASK;
+            break;
+    }
+    // Disable UART before changing registers
+    obj->uart->C2 &= ~(UART_C2_RE_MASK | UART_C2_TE_MASK);
+
+    switch (uart) {
+        case UART_0:
+            obj->index = 0;
+            break;
+        case UART_1:
+            obj->index = 1;
+            break;
+        case UART_2:
+            obj->index = 2;
+            break;
+    }
+
+    // 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);
+    }
+
+    obj->uart->C2 |= (UART_C2_RE_MASK | UART_C2_TE_MASK);
+
+    if (uart == STDIO_UART) {
+        stdio_uart_inited = 1;
+        memcpy(&stdio_uart, obj, sizeof(serial_t));
+    }
+}
+
+void serial_free(serial_t *obj) {
+    serial_irq_ids[obj->index] = 0;
+}
+
+void serial_baud(serial_t *obj, int baudrate) {
+    // save C2 state
+    uint8_t c2_state = (obj->uart->C2 & (UART_C2_RE_MASK | UART_C2_TE_MASK));
+    
+    // Disable UART before changing registers
+    obj->uart->C2 &= ~(UART_C2_RE_MASK | UART_C2_TE_MASK);
+    
+    uint32_t PCLK;
+    if (obj->uart != UART2) {
+        PCLK = mcgpllfll_frequency();
+    }
+    else {
+        PCLK = bus_frequency();
+    }
+    
+    uint16_t DL = PCLK / (16 * baudrate);
+    uint32_t BRFA = (2 * PCLK) / baudrate - 32 * DL;
+
+    // set BDH and BDL
+    obj->uart->BDH = (obj->uart->BDH & ~(0x1f)) | ((DL >> 8) & 0x1f);
+    obj->uart->BDL = (obj->uart->BDL & ~(0xff)) | ((DL >> 0) & 0xff);
+    
+    obj->uart->C4 &= ~0x1F;
+    obj->uart->C4 |= BRFA & 0x1F;    
+    
+    // restore C2 state
+    obj->uart->C2 |= c2_state;
+}
+
+void serial_format(serial_t *obj, int data_bits, SerialParity parity, int stop_bits) {
+    MBED_ASSERT((stop_bits == 1) || (stop_bits == 2));
+    MBED_ASSERT((parity == ParityNone) || (parity == ParityOdd) || (parity == ParityEven));
+    MBED_ASSERT((data_bits == 8) || (data_bits == 9));
+
+    // save C2 state
+    uint32_t c2_state = (obj->uart->C2 & (UART_C2_RE_MASK | UART_C2_TE_MASK));
+
+    // Disable UART before changing registers
+    obj->uart->C2 &= ~(UART_C2_RE_MASK | UART_C2_TE_MASK);
+
+    // 8 data bits = 0 ... 9 data bits = 1
+    data_bits -= 8;
+
+    uint32_t parity_enable, parity_select;
+    switch (parity) {
+        case ParityNone:
+            parity_enable = 0;
+            parity_select = 0;
+            break;
+        case ParityOdd :
+            parity_enable = 1;
+            parity_select = 1;
+            data_bits++;
+            break;
+        case ParityEven:
+            parity_enable = 1;
+            parity_select = 0;
+            data_bits++;
+            break;
+        default:
+            break;
+    }
+
+    stop_bits -= 1;
+
+    uint32_t m10 = 0;
+
+    // 9 data bits + parity - only uart0 support
+    if (data_bits == 2) {
+        MBED_ASSERT(obj->index == 0);
+        data_bits = 0;
+        m10 = 1;
+    }
+
+    // data bits, parity and parity mode
+    obj->uart->C1 = ((data_bits << 4)
+                  |  (parity_enable << 1)
+                  |  (parity_select << 0));
+
+    //enable 10bit mode if needed
+    if (obj->index == 0) {
+        obj->uart->C4 &= ~UART_C4_M10_MASK;
+        obj->uart->C4 |= (m10 << UART_C4_M10_SHIFT);
+    }
+
+    // stop bits
+    obj->uart->BDH &= ~UART_BDH_SBR_MASK;
+    obj->uart->BDH |= (stop_bits << UART_BDH_SBR_SHIFT);
+
+    // restore C2 state
+    obj->uart->C2 |= c2_state;
+}
+
+/******************************************************************************
+ * INTERRUPTS HANDLING
+ ******************************************************************************/
+static inline void uart_irq(uint8_t status, uint32_t index) {
+    if (serial_irq_ids[index] != 0) {
+        if (status & UART_S1_TDRE_MASK)
+            irq_handler(serial_irq_ids[index], TxIrq);
+
+        if (status & UART_S1_RDRF_MASK)
+            irq_handler(serial_irq_ids[index], RxIrq);
+    }
+}
+
+void uart0_irq() {uart_irq(UART0->S1, 0);}
+void uart1_irq() {uart_irq(UART1->S1, 1);}
+void uart2_irq() {uart_irq(UART2->S1, 2);}
+
+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;
+    switch ((int)obj->uart) {
+        case UART_0:
+            irq_n=UART0_RX_TX_IRQn;
+            vector = (uint32_t)&uart0_irq;
+            break;
+        case UART_1:
+            irq_n=UART1_RX_TX_IRQn;
+            vector = (uint32_t)&uart1_irq;
+            break;
+        case UART_2:
+            irq_n=UART2_RX_TX_IRQn;
+            vector = (uint32_t)&uart2_irq;
+            break;
+    }
+
+    if (enable) {
+        switch (irq) {
+            case RxIrq:
+                obj->uart->C2 |= (UART_C2_RIE_MASK);
+                break;
+            case TxIrq:
+                obj->uart->C2 |= (UART_C2_TIE_MASK);
+                break;
+        }
+        NVIC_SetVector(irq_n, vector);
+        NVIC_EnableIRQ(irq_n);
+
+    } else { // disable
+        int all_disabled = 0;
+        SerialIrq other_irq = (irq == RxIrq) ? (TxIrq) : (RxIrq);
+        switch (irq) {
+            case RxIrq:
+                obj->uart->C2 &= ~(UART_C2_RIE_MASK);
+                break;
+            case TxIrq:
+                obj->uart->C2 &= ~(UART_C2_TIE_MASK);
+                break;
+        }
+        switch (other_irq) {
+            case RxIrq:
+                all_disabled = (obj->uart->C2 & (UART_C2_RIE_MASK)) == 0;
+                break;
+            case TxIrq:
+                all_disabled = (obj->uart->C2 & (UART_C2_TIE_MASK)) == 0;
+                break;
+        }
+        if (all_disabled)
+            NVIC_DisableIRQ(irq_n);
+    }
+}
+
+int serial_getc(serial_t *obj) {
+    while (!serial_readable(obj));
+    return obj->uart->D;
+}
+
+void serial_putc(serial_t *obj, int c) {
+    while (!serial_writable(obj));
+    obj->uart->D = c;
+}
+
+int serial_readable(serial_t *obj) {
+
+    return (obj->uart->S1 & UART_S1_RDRF_MASK);
+}
+
+int serial_writable(serial_t *obj) {
+
+    return (obj->uart->S1 & UART_S1_TDRE_MASK);
+}
+
+void serial_clear(serial_t *obj) {
+}
+
+void serial_pinout_tx(PinName tx) {
+    pinmap_pinout(tx, PinMap_UART_TX);
+}
+
+void serial_break_set(serial_t *obj) {
+    obj->uart->C2 |= UART_C2_SBK_MASK;
+}
+
+void serial_break_clear(serial_t *obj) {
+    obj->uart->C2 &= ~UART_C2_SBK_MASK;
+}