Lee Kai Xuan
mbed-os
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mbed-os
by 
erkin yucel
Diff: targets/TARGET_NXP/TARGET_LPC2460/spi_api.c
- Revision:
- 0:f269e3021894
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_NXP/TARGET_LPC2460/spi_api.c Sun Oct 23 15:10:02 2016 +0000
@@ -0,0 +1,219 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2015 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 PinMap PinMap_SPI_SCLK[] = {
+ {P0_7 , SPI_1, 2},
+ {P0_15, SPI_0, 2},
+ {P1_20, SPI_0, 3},
+ {P1_31, SPI_1, 2},
+ {NC , NC , 0}
+};
+
+static const PinMap PinMap_SPI_MOSI[] = {
+ {P0_9 , SPI_1, 2},
+ {P0_13, SPI_1, 2},
+ {P0_18, SPI_0, 2},
+ {P1_24, SPI_0, 3},
+ {NC , NC , 0}
+};
+
+static const PinMap PinMap_SPI_MISO[] = {
+ {P0_8 , SPI_1, 2},
+ {P0_12, SPI_1, 2},
+ {P0_17, SPI_0, 2},
+ {P1_23, SPI_0, 3},
+ {NC , NC , 0}
+};
+
+static const PinMap PinMap_SPI_SSEL[] = {
+ {P0_6 , SPI_1, 2},
+ {P0_14, SPI_1, 3},
+ {P0_16, SPI_0, 2},
+ {P1_21, SPI_0, 3},
+ {NC , NC , 0}
+};
+
+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) {
+ // 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 = (LPC_SSP_TypeDef*)pinmap_merge(spi_data, spi_cntl);
+ MBED_ASSERT((int)obj->spi != NC);
+
+ // enable power and clocking
+ switch ((int)obj->spi) {
+ case SPI_0: LPC_SC->PCONP |= 1 << PCSSP0; break;
+ case SPI_1: LPC_SC->PCONP |= 1 << PCSSP1; 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 the ssp channel
+ ssp_enable(obj);
+
+ // 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) {}
+
+void spi_format(spi_t *obj, int bits, int mode, int slave) {
+ MBED_ASSERT(((bits >= 4) && (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
+
+ int FRF = 0; // FRF (frame format) = SPI
+ uint32_t tmp = obj->spi->CR0;
+ tmp &= ~(0xFFFF);
+ tmp |= DSS << 0
+ | FRF << 4
+ | SPO << 6
+ | SPH << 7;
+ obj->spi->CR0 = tmp;
+
+ tmp = obj->spi->CR1;
+ tmp &= ~(0xD);
+ tmp |= 0 << 0 // LBM - loop back mode - off
+ | ((slave) ? 1 : 0) << 2 // MS - master slave mode, 1 = slave
+ | 0 << 3; // SOD - slave output disable - na
+ obj->spi->CR1 = tmp;
+
+ ssp_enable(obj);
+}
+
+void spi_frequency(spi_t *obj, int hz) {
+ ssp_disable(obj);
+
+ // setup the spi clock diveder to /1
+ switch ((int)obj->spi) {
+ case SPI_0:
+ LPC_SC->PCLKSEL1 &= ~(3 << 10);
+ LPC_SC->PCLKSEL1 |= (1 << 10);
+ break;
+ case SPI_1:
+ LPC_SC->PCLKSEL0 &= ~(3 << 20);
+ LPC_SC->PCLKSEL0 |= (1 << 20);
+ break;
+ }
+
+ uint32_t PCLK = SystemCoreClock;
+
+ int prescaler;
+
+ for (prescaler = 2; prescaler <= 254; prescaler += 2) {
+ int prescale_hz = PCLK / prescaler;
+
+ // calculate the divider
+ int divider = floor(((float)prescale_hz / (float)hz) + 0.5f);
+
+ // check we can support the divider
+ if (divider < 256) {
+ // prescaler
+ obj->spi->CPSR = prescaler;
+
+ // divider
+ obj->spi->CR0 &= ~(0xFFFF << 8);
+ obj->spi->CR0 |= (divider - 1) << 8;
+ ssp_enable(obj);
+ return;
+ }
+ }
+ error("Couldn't setup requested SPI frequency");
+}
+
+static inline int ssp_disable(spi_t *obj) {
+ return obj->spi->CR1 &= ~(1 << 1);
+}
+
+static inline int ssp_enable(spi_t *obj) {
+ return obj->spi->CR1 |= (1 << 1);
+}
+
+static inline int ssp_readable(spi_t *obj) {
+ return obj->spi->SR & (1 << 2);
+}
+
+static inline int ssp_writeable(spi_t *obj) {
+ return obj->spi->SR & (1 << 1);
+}
+
+static inline void ssp_write(spi_t *obj, int value) {
+ while (!ssp_writeable(obj));
+ obj->spi->DR = value;
+}
+
+static inline int ssp_read(spi_t *obj) {
+ while (!ssp_readable(obj));
+ return obj->spi->DR;
+}
+
+static inline int ssp_busy(spi_t *obj) {
+ return (obj->spi->SR & (1 << 4)) ? (1) : (0);
+}
+
+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->DR;
+}
+
+void spi_slave_write(spi_t *obj, int value) {
+ while (ssp_writeable(obj) == 0) ;
+ obj->spi->DR = value;
+}
+
+int spi_busy(spi_t *obj) {
+ return ssp_busy(obj);
+}