Diff: targets/TARGET_NXP/TARGET_LPC81X/spi_api.c

Revision:

0:f269e3021894

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_NXP/TARGET_LPC81X/spi_api.c	Sun Oct 23 15:10:02 2016 +0000
@@ -0,0 +1,196 @@
+/* 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, 16},
+    {5, 16},
+};
+
+static const SWM_Map SWM_SPI_SCLK[] = {
+    {3, 24},
+    {4, 24},
+};
+
+static const SWM_Map SWM_SPI_MOSI[] = {
+    {4, 0},
+    {5, 0},
+};
+
+static const SWM_Map SWM_SPI_MISO[] = {
+    {4, 8},
+    {5, 16},
+};
+
+// 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 int ssp_disable(spi_t *obj);
+static inline int ssp_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_SPI_TypeDef *)(LPC_SPI1_BASE) : (LPC_SPI_TypeDef *)(LPC_SPI0_BASE);
+    
+    const SWM_Map *swm;
+    uint32_t regVal;
+    
+    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);
+    
+    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);
+    
+    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);
+    
+    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
+    switch (obj->spi_n) {
+        case 0:
+            LPC_SYSCON->SYSAHBCLKCTRL |= (1<<11);
+            LPC_SYSCON->PRESETCTRL &= ~(0x1<<0);
+            LPC_SYSCON->PRESETCTRL |= (0x1<<0);
+            break;
+        case 1:
+            LPC_SYSCON->SYSAHBCLKCTRL |= (1<<12);
+            LPC_SYSCON->PRESETCTRL &= ~(0x1<<1);
+            LPC_SYSCON->PRESETCTRL |= (0x1<<1);
+            break;
+    }
+}
+
+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)));
+    ssp_disable(obj);
+    
+    int polarity = (mode & 0x2) ? 1 : 0;
+    int phase = (mode & 0x1) ? 1 : 0;
+    
+    // set it up
+    int DSS = bits - 1;            // DSS (data select size)
+    int SPO = (polarity) ? 1 : 0;  // SPO - clock out polarity
+    int SPH = (phase) ? 1 : 0;     // SPH - clock out phase
+    
+    uint32_t tmp = obj->spi->CFG;
+    tmp &= ~((1 << 2) | (1 << 4) | (1 << 5));
+    tmp |= (SPH << 4) | (SPO << 5) | ((slave ? 0 : 1) << 2);
+    obj->spi->CFG = tmp;
+    
+    // select frame length
+    tmp = obj->spi->TXDATCTL;
+    tmp &= ~(0xf << 24);
+    tmp |= (DSS << 24);
+    obj->spi->TXDATCTL = tmp;
+    
+    ssp_enable(obj);
+}
+
+void spi_frequency(spi_t *obj, int hz) {
+    ssp_disable(obj);
+    
+    uint32_t PCLK = SystemCoreClock;
+    
+    obj->spi->DIV = PCLK/hz - 1;
+    obj->spi->DLY = 0;
+    ssp_enable(obj);
+}
+
+static inline int ssp_disable(spi_t *obj) {
+    return obj->spi->CFG &= ~(1 << 0);
+}
+
+static inline int ssp_enable(spi_t *obj) {
+    return obj->spi->CFG |= (1 << 0);
+}
+
+static inline int ssp_readable(spi_t *obj) {
+    return obj->spi->STAT & (1 << 0);
+}
+
+static inline int ssp_writeable(spi_t *obj) {
+    return obj->spi->STAT & (1 << 1);
+}
+
+static inline void ssp_write(spi_t *obj, int value) {
+    while (!ssp_writeable(obj));
+    // end of transfer
+    obj->spi->TXDATCTL |= (1 << 20);
+    obj->spi->TXDAT = value;
+}
+
+static inline int ssp_read(spi_t *obj) {
+    while (!ssp_readable(obj));
+    return obj->spi->RXDAT;
+}
+
+static inline int ssp_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) {
+    ssp_write(obj, value);
+    return ssp_read(obj);
+}
+
+int spi_slave_receive(spi_t *obj) {
+    return (ssp_readable(obj) && !ssp_busy(obj)) ? (1) : (0);
+}
+
+int spi_slave_read(spi_t *obj) {
+    return obj->spi->RXDAT;
+}
+
+void spi_slave_write(spi_t *obj, int value) {
+    while (ssp_writeable(obj) == 0) ;
+    obj->spi->TXDAT = value;
+}
+
+int spi_busy(spi_t *obj) {
+    return ssp_busy(obj);
+}