Diff: vendor/Freescale/KL25Z/hal/spi_api.c

Revision:

10:3bc89ef62ce7

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/vendor/Freescale/KL25Z/hal/spi_api.c	Fri Jun 14 17:49:17 2013 +0100
@@ -0,0 +1,175 @@
+/* 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 "spi_api.h"
+
+#include <math.h>
+
+#include "cmsis.h"
+#include "pinmap.h"
+#include "error.h"
+
+static const PinMap PinMap_SPI_SCLK[] = {
+    {PTE2, SPI_1, 2},
+    {PTC5, SPI_0, 2},
+    {PTD1, SPI_0, 2},
+    {NC  , NC   , 0}
+};
+
+static const PinMap PinMap_SPI_MOSI[] = {
+    {PTE1, SPI_1, 2},
+    {PTC6, SPI_0, 2},
+    {PTD2, SPI_0, 2},
+    {NC  , NC   , 0}
+};
+
+static const PinMap PinMap_SPI_MISO[] = {
+    {PTE3, SPI_1, 2},
+    {PTC7, SPI_0, 2},
+    {PTD3, SPI_0, 2},
+    {NC   , NC   , 0}
+};
+
+static const PinMap PinMap_SPI_SSEL[] = {
+    {PTE4, SPI_1, 2},
+    {PTC4, SPI_0, 2},
+    {PTD0, SPI_0, 2},
+    {NC  , NC   , 0}
+};
+
+void spi_init(spi_t *obj, PinName mosi, PinName miso, PinName sclk, PinName ssel) {
+    // determine the SPI to use
+    SPIName spi_mosi = (SPIName)pinmap_peripheral(mosi, PinMap_SPI_MOSI);
+    SPIName spi_miso = (SPIName)pinmap_peripheral(miso, PinMap_SPI_MISO);
+    SPIName spi_sclk = (SPIName)pinmap_peripheral(sclk, PinMap_SPI_SCLK);
+    SPIName spi_ssel = (SPIName)pinmap_peripheral(ssel, PinMap_SPI_SSEL);
+    SPIName spi_data = (SPIName)pinmap_merge(spi_mosi, spi_miso);
+    SPIName spi_cntl = (SPIName)pinmap_merge(spi_sclk, spi_ssel);
+
+    obj->spi = (SPI_Type*)pinmap_merge(spi_data, spi_cntl);
+    if ((int)obj->spi == NC) {
+        error("SPI pinout mapping failed");
+    }
+
+    // enable power and clocking
+    switch ((int)obj->spi) {
+        case SPI_0: SIM->SCGC5 |= 1 << 11; SIM->SCGC4 |= 1 << 22; break;
+        case SPI_1: SIM->SCGC5 |= 1 << 13; SIM->SCGC4 |= 1 << 23; break;
+    }
+
+    // set default format and frequency
+    if (ssel == NC) {
+        spi_format(obj, 8, 0, 0);  // 8 bits, mode 0, master
+    } else {
+        spi_format(obj, 8, 0, 1);  // 8 bits, mode 0, slave
+    }
+    spi_frequency(obj, 1000000);
+
+    // enable SPI
+    obj->spi->C1 |= SPI_C1_SPE_MASK;
+
+    // pin out the spi pins
+    pinmap_pinout(mosi, PinMap_SPI_MOSI);
+    pinmap_pinout(miso, PinMap_SPI_MISO);
+    pinmap_pinout(sclk, PinMap_SPI_SCLK);
+    if (ssel != NC) {
+        pinmap_pinout(ssel, PinMap_SPI_SSEL);
+    }
+}
+
+void spi_free(spi_t *obj) {
+    // [TODO]
+}
+void spi_format(spi_t *obj, int bits, int mode, int slave) {
+    if (bits != 8) {
+        error("Only 8bits SPI supported");
+    }
+
+    if ((mode < 0) || (mode > 3)) {
+        error("SPI mode unsupported");
+    }
+
+    uint8_t polarity = (mode & 0x2) ? 1 : 0;
+    uint8_t phase = (mode & 0x1) ? 1 : 0;
+    uint8_t c1_data = ((!slave) << 4) | (polarity << 3) | (phase << 2);
+
+    // clear MSTR, CPOL and CPHA bits
+    obj->spi->C1 &= ~(0x7 << 2);
+
+    // write new value
+    obj->spi->C1 |= c1_data;
+}
+
+void spi_frequency(spi_t *obj, int hz) {
+    uint32_t error = 0;
+    uint32_t p_error = 0xffffffff;
+    uint32_t ref = 0;
+    uint8_t  spr = 0;
+    uint8_t  ref_spr = 0;
+    uint8_t  ref_prescaler = 0;
+
+    // bus clk
+    uint32_t PCLK = 48000000u;
+    uint8_t prescaler = 1;
+    uint8_t divisor = 2;
+
+    for (prescaler = 1; prescaler <= 8; prescaler++) {
+        divisor = 2;
+        for (spr = 0; spr <= 8; spr++) {
+            ref = PCLK / (prescaler*divisor);
+            error = (ref > hz) ? ref - hz : hz - ref;
+            if (error < p_error) {
+                ref_spr = spr;
+                ref_prescaler = prescaler - 1;
+                p_error = error;
+            }
+            divisor *= 2;
+        }
+    }
+
+    // set SPPR and SPR
+    obj->spi->BR = ((ref_prescaler & 0x7) << 4) | (ref_spr & 0xf);
+}
+
+static inline int spi_writeable(spi_t * obj) {
+    return (obj->spi->S & SPI_S_SPTEF_MASK) ? 1 : 0;
+}
+
+static inline int spi_readable(spi_t * obj) {
+    return (obj->spi->S & SPI_S_SPRF_MASK) ? 1 : 0;
+}
+
+int spi_master_write(spi_t *obj, int value) {
+    // wait tx buffer empty
+    while(!spi_writeable(obj));
+    obj->spi->D = (value & 0xff);
+
+    // wait rx buffer full
+    while (!spi_readable(obj));
+    return obj->spi->D & 0xff;
+}
+
+int spi_slave_receive(spi_t *obj) {
+    return spi_readable(obj);
+}
+
+int spi_slave_read(spi_t *obj) {
+    return obj->spi->D;
+}
+
+void spi_slave_write(spi_t *obj, int value) {
+    while (!spi_writeable(obj));
+    obj->spi->D = value;
+}