Diff: targets/TARGET_NXP/TARGET_LPC15XX/spi_api.c

Revision:

149:156823d33999

Parent:

144:ef7eb2e8f9f7

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_NXP/TARGET_LPC15XX/spi_api.c	Fri Oct 28 11:17:30 2016 +0100
@@ -0,0 +1,265 @@
+/* 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.
+ */
+#include "mbed_assert.h"
+#include <math.h>
+
+#include "spi_api.h"
+#include "cmsis.h"
+#include "pinmap.h"
+#include "mbed_error.h"
+
+static const SWM_Map SWM_SPI_SSEL[] = {
+    {4, 0},
+    {5, 24},
+};
+
+static const SWM_Map SWM_SPI_SCLK[] = {
+    {3, 8},
+    {5, 0},
+};
+
+static const SWM_Map SWM_SPI_MOSI[] = {
+    {3, 16},
+    {5, 8},
+};
+
+static const SWM_Map SWM_SPI_MISO[] = {
+    {3, 24},
+    {5, 16},
+};
+
+// bit flags for used SPIs
+static unsigned char spi_used = 0;
+static int get_available_spi(PinName mosi, PinName miso, PinName sclk, PinName ssel)
+{
+    if (spi_used == 0) {
+        return 0; // The first user
+    }
+
+    const SWM_Map *swm;
+    uint32_t regVal;
+
+    // Investigate if same pins as the used SPI0/1 - to be able to reuse it
+    for (int spi_n = 0; spi_n < 2; spi_n++) {
+        if (spi_used & (1<<spi_n)) {
+            if (sclk != NC) {
+                swm = &SWM_SPI_SCLK[spi_n];
+                regVal = LPC_SWM->PINASSIGN[swm->n] & (0xFF << swm->offset);
+                if (regVal != (sclk << swm->offset)) {
+                    // Existing pin is not the same as the one we want
+                    continue;
+                }
+            }
+
+            if (mosi != NC) {
+                swm = &SWM_SPI_MOSI[spi_n];
+                regVal = LPC_SWM->PINASSIGN[swm->n] & (0xFF << swm->offset);
+                if (regVal != (mosi << swm->offset)) {
+                    // Existing pin is not the same as the one we want
+                    continue;
+                }
+            }
+
+            if (miso != NC) {
+                swm = &SWM_SPI_MISO[spi_n];
+                regVal = LPC_SWM->PINASSIGN[swm->n] & (0xFF << swm->offset);
+                if (regVal != (miso << swm->offset)) {
+                    // Existing pin is not the same as the one we want
+                    continue;
+                }
+            }
+
+            if (ssel != NC) {
+                swm = &SWM_SPI_SSEL[spi_n];
+                regVal = LPC_SWM->PINASSIGN[swm->n] & (0xFF << swm->offset);
+                if (regVal != (ssel << swm->offset)) {
+                    // Existing pin is not the same as the one we want
+                    continue;
+                }
+            }
+
+            // The pins for the currently used SPIx are the same as the
+            // ones we want so we will reuse it
+            return spi_n;
+        }
+    }
+
+    // None of the existing SPIx pin setups match the pins we want
+    // so the last hope is to select one unused SPIx
+    if ((spi_used & 1) == 0) {
+        return 0;
+    } else if ((spi_used & 2) == 0) {
+        return 1;
+    }
+
+    // No matching setup and no free SPIx
+    return -1;
+}
+
+static inline void spi_disable(spi_t *obj);
+static inline void spi_enable(spi_t *obj);
+
+void spi_init(spi_t *obj, PinName mosi, PinName miso, PinName sclk, PinName ssel)
+{
+    int spi_n = get_available_spi(mosi, miso, sclk, ssel);
+    if (spi_n == -1) {
+        error("No available SPI");
+    }
+
+    obj->spi_n = spi_n;
+    spi_used |= (1 << spi_n);
+
+    obj->spi = (spi_n) ? (LPC_SPI0_Type *)(LPC_SPI1_BASE) : (LPC_SPI0_Type *)(LPC_SPI0_BASE);
+
+    const SWM_Map *swm;
+    uint32_t regVal;
+
+    if (sclk != NC) {
+        swm = &SWM_SPI_SCLK[obj->spi_n];
+        regVal = LPC_SWM->PINASSIGN[swm->n] & ~(0xFF << swm->offset);
+        LPC_SWM->PINASSIGN[swm->n] = regVal |  (sclk   << swm->offset);
+    }
+
+    if (mosi != NC) {
+        swm = &SWM_SPI_MOSI[obj->spi_n];
+        regVal = LPC_SWM->PINASSIGN[swm->n] & ~(0xFF << swm->offset);
+        LPC_SWM->PINASSIGN[swm->n] = regVal |  (mosi   << swm->offset);
+    }
+
+    if (miso != NC) {
+        swm = &SWM_SPI_MISO[obj->spi_n];
+        regVal = LPC_SWM->PINASSIGN[swm->n] & ~(0xFF << swm->offset);
+        LPC_SWM->PINASSIGN[swm->n] = regVal |  (miso   << swm->offset);
+    }
+
+    if (ssel != NC) {
+        swm = &SWM_SPI_SSEL[obj->spi_n];
+        regVal = LPC_SWM->PINASSIGN[swm->n] & ~(0xFF << swm->offset);
+        LPC_SWM->PINASSIGN[swm->n] = regVal |  (ssel   << swm->offset);
+    }
+
+    // clear interrupts
+    obj->spi->INTENCLR = 0x3f;
+
+    // enable power and clocking
+    LPC_SYSCON->SYSAHBCLKCTRL1 |=  (0x1 << (obj->spi_n + 9));
+    LPC_SYSCON->PRESETCTRL1    |=  (0x1 << (obj->spi_n + 9));
+    LPC_SYSCON->PRESETCTRL1    &= ~(0x1 << (obj->spi_n + 9));
+}
+
+void spi_free(spi_t *obj)
+{
+}
+
+void spi_format(spi_t *obj, int bits, int mode, int slave)
+{
+    spi_disable(obj);
+    MBED_ASSERT((bits >= 1 && bits <= 16) && (mode >= 0 && mode <= 3));
+
+    int polarity = (mode & 0x2) ? 1 : 0;
+    int phase = (mode & 0x1) ? 1 : 0;
+
+    // set it up
+    int LEN = bits - 1;             // LEN  - Data Length
+    int CPOL = (polarity) ? 1 : 0;  // CPOL - Clock Polarity select
+    int CPHA = (phase) ? 1 : 0;     // CPHA - Clock Phase select
+
+    uint32_t tmp = obj->spi->CFG;
+    tmp &= ~((1 << 5) | (1 << 4) | (1 << 2));
+    tmp |= (CPOL << 5) | (CPHA << 4) | ((slave ? 0 : 1) << 2);
+    obj->spi->CFG = tmp;
+
+    // select frame length
+    tmp = obj->spi->TXCTL;
+    tmp &= ~(0xf << 24);
+    tmp |= (LEN << 24);
+    obj->spi->TXCTL = tmp;
+
+    spi_enable(obj);
+}
+
+void spi_frequency(spi_t *obj, int hz)
+{
+    spi_disable(obj);
+
+    // rise DIV value if it cannot be divided
+    obj->spi->DIV = (SystemCoreClock + (hz - 1))/hz - 1;
+    obj->spi->DLY = 0;
+
+    spi_enable(obj);
+}
+
+static inline void spi_disable(spi_t *obj)
+{
+    obj->spi->CFG &= ~(1 << 0);
+}
+
+static inline void spi_enable(spi_t *obj)
+{
+    obj->spi->CFG |= (1 << 0);
+}
+
+static inline int spi_readable(spi_t *obj)
+{
+    return obj->spi->STAT & (1 << 0);
+}
+
+static inline int spi_writeable(spi_t *obj)
+{
+    return obj->spi->STAT & (1 << 1);
+}
+
+static inline void spi_write(spi_t *obj, int value)
+{
+    while (!spi_writeable(obj));
+    // end of transfer
+    obj->spi->TXCTL |= (1 << 20);
+    obj->spi->TXDAT = (value & 0xffff);
+}
+
+static inline int spi_read(spi_t *obj)
+{
+    while (!spi_readable(obj));
+    return obj->spi->RXDAT & 0xffff; // Only the lower 16 bits contain data
+}
+
+int spi_busy(spi_t *obj)
+{
+    // checking RXOV(Receiver Overrun interrupt flag)
+    return obj->spi->STAT & (1 << 2);
+}
+
+int spi_master_write(spi_t *obj, int value)
+{
+    spi_write(obj, value);
+    return spi_read(obj);
+}
+
+int spi_slave_receive(spi_t *obj)
+{
+    return (spi_readable(obj) && !spi_busy(obj)) ? (1) : (0);
+}
+
+int spi_slave_read(spi_t *obj)
+{
+    return obj->spi->RXDAT & 0xffff; // Only the lower 16 bits contain data
+}
+
+void spi_slave_write(spi_t *obj, int value)
+{
+    while (spi_writeable(obj) == 0) ;
+    obj->spi->TXDAT = value;
+}