Diff: mbed-dev/targets/TARGET_NXP/TARGET_LPC82X/spi_api.c

Revision:

18:6a4db94011d3

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed-dev/targets/TARGET_NXP/TARGET_LPC82X/spi_api.c	Sun May 14 23:18:57 2017 +0000
@@ -0,0 +1,199 @@
+/* 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 "spi_api.h"
+#include "cmsis.h"
+#include "pinmap.h"
+#include "mbed_error.h"
+
+#if DEVICE_SPI
+
+static const SWM_Map SWM_SPI_SSEL[] = {
+    {4, 16},
+    {6, 8},
+};
+
+static const SWM_Map SWM_SPI_SCLK[] = {
+    {3, 24},
+    {5, 16},
+};
+
+static const SWM_Map SWM_SPI_MOSI[] = {
+    {4, 0},
+    {5, 24},
+};
+
+static const SWM_Map SWM_SPI_MISO[] = {
+    {4, 8},
+    {6, 0},
+};
+
+// bit flags for used SPIs
+static unsigned char spi_used = 0;
+
+static int get_available_spi(void)
+{
+    int i;
+    for (i=0; i<2; i++) {
+        if ((spi_used & (1 << i)) == 0)
+            return i;
+    }
+    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();
+    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 != (PinName)NC) {
+        swm = &SWM_SPI_SCLK[obj->spi_n];
+        regVal = LPC_SWM->PINASSIGN[swm->n] & ~(0xFF << swm->offset);
+        LPC_SWM->PINASSIGN[swm->n] = regVal |  ((sclk >> PIN_SHIFT) << swm->offset);
+    }
+
+    if (mosi != (PinName)NC) {
+        swm = &SWM_SPI_MOSI[obj->spi_n];
+        regVal = LPC_SWM->PINASSIGN[swm->n] & ~(0xFF << swm->offset);
+        LPC_SWM->PINASSIGN[swm->n] = regVal |  ((mosi >> PIN_SHIFT) << swm->offset);
+    }
+
+    if (miso != (PinName)NC) {
+        swm = &SWM_SPI_MISO[obj->spi_n];
+        regVal = LPC_SWM->PINASSIGN[swm->n] & ~(0xFF << swm->offset);
+        LPC_SWM->PINASSIGN[swm->n] = regVal |  ((miso >> PIN_SHIFT) << swm->offset);
+    }
+
+    if (ssel != (PinName)NC) {
+        swm = &SWM_SPI_SSEL[obj->spi_n];
+        regVal = LPC_SWM->PINASSIGN[swm->n] & ~(0xFF << swm->offset);
+        LPC_SWM->PINASSIGN[swm->n] = regVal |  ((ssel >> PIN_SHIFT) << swm->offset);
+    }
+
+    // clear interrupts
+    obj->spi->INTENCLR = 0x3f;
+
+    LPC_SYSCON->SYSAHBCLKCTRL |=  (1 << (11 + obj->spi_n));
+    LPC_SYSCON->PRESETCTRL    &= ~(1 << obj->spi_n);
+    LPC_SYSCON->PRESETCTRL    |=  (1 << obj->spi_n);
+
+    obj->spi->DLY = 2;             // 2 SPI clock times pre-delay
+}
+
+void spi_free(spi_t *obj)
+{
+}
+
+void spi_format(spi_t *obj, int bits, int mode, int slave)
+{
+    MBED_ASSERT(((bits >= 1) && (bits <= 16)) && ((mode >= 0) && (mode <= 3)));
+    spi_disable(obj);
+
+    obj->spi->CFG &= ~((0x3 << 4) | (1 << 2));
+    obj->spi->CFG |=  ((mode & 0x3) << 4) | ((slave ? 0 : 1) << 2);
+
+    obj->spi->TXCTL &= ~( 0xF << 24);
+    obj->spi->TXCTL |=  ((bits - 1) << 24);
+
+    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;
+
+    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);
+}
+
+int spi_master_write(spi_t *obj, int value)
+{
+    spi_write(obj, value);
+    return spi_read(obj);
+}
+
+int spi_busy(spi_t *obj)
+{
+    // checking RXOV(Receiver Overrun interrupt flag)
+    return obj->spi->STAT & (1 << 2);
+}
+
+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);
+}
+
+void spi_slave_write(spi_t *obj, int value)
+{
+    while (spi_writeable(obj) == 0);
+    obj->spi->TXDAT = value;
+}
+
+#endif