Lee Kai Xuan
mbed-os
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erkin yucel
Diff: targets/TARGET_NXP/TARGET_LPC15XX/spi_api.c
- Revision:
- 0:f269e3021894
diff -r 000000000000 -r f269e3021894 targets/TARGET_NXP/TARGET_LPC15XX/spi_api.c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_NXP/TARGET_LPC15XX/spi_api.c Sun Oct 23 15:10:02 2016 +0000
@@ -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;
+}