Diff: targets/TARGET_NUVOTON/TARGET_NUC472/spi_api.c

Revision:

149:156823d33999

Child:

153:fa9ff456f731

diff -r 21d94c44109e -r 156823d33999 targets/TARGET_NUVOTON/TARGET_NUC472/spi_api.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_NUVOTON/TARGET_NUC472/spi_api.c	Fri Oct 28 11:17:30 2016 +0100
@@ -0,0 +1,768 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2015-2016 Nuvoton
+ *
+ * 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"
+
+#if DEVICE_SPI
+
+#include "cmsis.h"
+#include "pinmap.h"
+#include "PeripheralPins.h"
+#include "nu_modutil.h"
+#include "nu_miscutil.h"
+#include "nu_bitutil.h"
+
+#if DEVICE_SPI_ASYNCH
+#include "dma_api.h"
+#include "dma.h"
+#endif
+
+#define NU_SPI_FRAME_MIN    8
+#define NU_SPI_FRAME_MAX    32
+#define NU_SPI_FIFO_DEPTH   8
+
+struct nu_spi_var {
+#if DEVICE_SPI_ASYNCH
+    uint8_t     pdma_perp_tx;
+    uint8_t     pdma_perp_rx;
+#endif
+};
+
+static struct nu_spi_var spi0_var = {
+#if DEVICE_SPI_ASYNCH
+    .pdma_perp_tx       =   PDMA_SPI0_TX,
+    .pdma_perp_rx       =   PDMA_SPI0_RX
+#endif
+};
+static struct nu_spi_var spi1_var = {
+#if DEVICE_SPI_ASYNCH
+    .pdma_perp_tx       =   PDMA_SPI1_TX,
+    .pdma_perp_rx       =   PDMA_SPI1_RX
+#endif
+};
+static struct nu_spi_var spi2_var = {
+#if DEVICE_SPI_ASYNCH
+    .pdma_perp_tx       =   PDMA_SPI2_TX,
+    .pdma_perp_rx       =   PDMA_SPI2_RX
+#endif
+};
+static struct nu_spi_var spi3_var = {
+#if DEVICE_SPI_ASYNCH
+    .pdma_perp_tx       =   PDMA_SPI3_TX,
+    .pdma_perp_rx       =   PDMA_SPI3_RX
+#endif
+};
+
+#if DEVICE_SPI_ASYNCH
+static void spi_enable_vector_interrupt(spi_t *obj, uint32_t handler, uint8_t enable);
+static void spi_master_enable_interrupt(spi_t *obj, uint8_t enable);
+static uint32_t spi_master_write_asynch(spi_t *obj, uint32_t tx_limit);
+static uint32_t spi_master_read_asynch(spi_t *obj);
+static uint32_t spi_event_check(spi_t *obj);
+static void spi_enable_event(spi_t *obj, uint32_t event, uint8_t enable);
+static void spi_buffer_set(spi_t *obj, const void *tx, size_t tx_length, void *rx, size_t rx_length);
+static void spi_check_dma_usage(DMAUsage *dma_usage, int *dma_ch_tx, int *dma_ch_rx);
+static uint8_t spi_get_data_width(spi_t *obj);
+static int spi_is_tx_complete(spi_t *obj);
+static int spi_is_rx_complete(spi_t *obj);
+static int spi_writeable(spi_t * obj);
+static int spi_readable(spi_t * obj);
+static void spi_dma_handler_tx(uint32_t id, uint32_t event_dma);
+static void spi_dma_handler_rx(uint32_t id, uint32_t event_dma);
+#endif
+
+static uint32_t spi_modinit_mask = 0;
+
+static const struct nu_modinit_s spi_modinit_tab[] = {
+    {SPI_0, SPI0_MODULE, 0, 0, SPI0_RST, SPI0_IRQn, &spi0_var},
+    {SPI_1, SPI1_MODULE, 0, 0, SPI1_RST, SPI1_IRQn, &spi1_var},
+    {SPI_2, SPI2_MODULE, 0, 0, SPI2_RST, SPI2_IRQn, &spi2_var},
+    {SPI_3, SPI3_MODULE, 0, 0, SPI3_RST, SPI3_IRQn, &spi3_var},
+    
+    {NC, 0, 0, 0, 0, (IRQn_Type) 0, NULL}
+};
+
+void spi_init(spi_t *obj, PinName mosi, PinName miso, PinName sclk, PinName ssel) {
+    // Determine which SPI_x the pins are used for
+    uint32_t spi_mosi = pinmap_peripheral(mosi, PinMap_SPI_MOSI);
+    uint32_t spi_miso = pinmap_peripheral(miso, PinMap_SPI_MISO);
+    uint32_t spi_sclk = pinmap_peripheral(sclk, PinMap_SPI_SCLK);
+    uint32_t spi_ssel = pinmap_peripheral(ssel, PinMap_SPI_SSEL);
+    uint32_t spi_data = pinmap_merge(spi_mosi, spi_miso);
+    uint32_t spi_cntl = pinmap_merge(spi_sclk, spi_ssel);
+    obj->spi.spi = (SPIName) pinmap_merge(spi_data, spi_cntl);
+    MBED_ASSERT((int)obj->spi.spi != NC);
+
+    const struct nu_modinit_s *modinit = get_modinit(obj->spi.spi, spi_modinit_tab);
+    MBED_ASSERT(modinit != NULL);
+    MBED_ASSERT(modinit->modname == obj->spi.spi);
+    
+    // Reset this module
+    SYS_ResetModule(modinit->rsetidx);
+    
+    // Enable IP clock
+    CLK_EnableModuleClock(modinit->clkidx);
+
+    //SPI_T *spi_base = (SPI_T *) NU_MODBASE(obj->spi.spi);
+    
+    pinmap_pinout(mosi, PinMap_SPI_MOSI);
+    pinmap_pinout(miso, PinMap_SPI_MISO);
+    pinmap_pinout(sclk, PinMap_SPI_SCLK);
+    pinmap_pinout(ssel, PinMap_SPI_SSEL);
+        
+    obj->spi.pin_mosi = mosi;
+    obj->spi.pin_miso = miso;
+    obj->spi.pin_sclk = sclk;
+    obj->spi.pin_ssel = ssel;
+    
+    // Configure the SPI data format and frequency
+    //spi_format(obj, 8, 0, SPI_MSB); // 8 bits, mode 0
+    //spi_frequency(obj, 1000000);
+    
+#if DEVICE_SPI_ASYNCH
+    obj->spi.dma_usage = DMA_USAGE_NEVER;
+    obj->spi.event = 0;
+    obj->spi.dma_chn_id_tx = DMA_ERROR_OUT_OF_CHANNELS;
+    obj->spi.dma_chn_id_rx = DMA_ERROR_OUT_OF_CHANNELS;
+#endif
+
+    // Mark this module to be inited.
+    int i = modinit - spi_modinit_tab;
+    spi_modinit_mask |= 1 << i;
+}
+
+void spi_free(spi_t *obj)
+{
+#if DEVICE_SPI_ASYNCH
+    if (obj->spi.dma_chn_id_tx != DMA_ERROR_OUT_OF_CHANNELS) {
+        dma_channel_free(obj->spi.dma_chn_id_tx);
+        obj->spi.dma_chn_id_tx = DMA_ERROR_OUT_OF_CHANNELS;
+    }
+    if (obj->spi.dma_chn_id_rx != DMA_ERROR_OUT_OF_CHANNELS) {
+        dma_channel_free(obj->spi.dma_chn_id_rx);
+        obj->spi.dma_chn_id_rx = DMA_ERROR_OUT_OF_CHANNELS;
+    }
+#endif
+
+    SPI_Close((SPI_T *) NU_MODBASE(obj->spi.spi));
+    
+    const struct nu_modinit_s *modinit = get_modinit(obj->spi.spi, spi_modinit_tab);
+    MBED_ASSERT(modinit != NULL);
+    MBED_ASSERT(modinit->modname == obj->spi.spi);
+    
+    SPI_DisableInt(((SPI_T *) NU_MODBASE(obj->spi.spi)), (SPI_FIFO_RXOVIEN_MASK | SPI_FIFO_RXTHIEN_MASK | SPI_FIFO_TXTHIEN_MASK));
+    NVIC_DisableIRQ(modinit->irq_n);
+    
+    // Disable IP clock
+    CLK_DisableModuleClock(modinit->clkidx);
+    
+    //((struct nu_spi_var *) modinit->var)->obj = NULL;
+    
+    // Mark this module to be deinited.
+    int i = modinit - spi_modinit_tab;
+    spi_modinit_mask &= ~(1 << i);
+}
+void spi_format(spi_t *obj, int bits, int mode, int slave)
+{
+    MBED_ASSERT(bits >= NU_SPI_FRAME_MIN && bits <= NU_SPI_FRAME_MAX);
+    
+    SPI_T *spi_base = (SPI_T *) NU_MODBASE(obj->spi.spi);
+    
+    // NOTE 1: All configurations should be ready before enabling SPI peripheral.
+    // NOTE 2: Re-configuration is allowed only as SPI peripheral is idle.
+    while (SPI_IS_BUSY(spi_base));
+    SPI_DISABLE(spi_base);
+    
+    SPI_Open(spi_base,
+        slave ? SPI_SLAVE : SPI_MASTER,
+        (mode == 0) ? SPI_MODE_0 : (mode == 1) ? SPI_MODE_1 : (mode == 2) ? SPI_MODE_2 : SPI_MODE_3,
+        bits,
+        SPI_GetBusClock(spi_base));
+    // NOTE: Hardcode to be MSB first.
+    SPI_SET_MSB_FIRST(spi_base);
+    
+    if (! slave) {
+        // Master
+        if (obj->spi.pin_ssel != NC) {
+            // Configure SS as low active.            
+            SPI_EnableAutoSS(spi_base, SPI_SS0, SPI_SS_ACTIVE_LOW);
+            // NOTE: In NUC472 series, all SPI SS pins are SS0, so we can hardcode SS0 here.
+        }
+        else {
+            SPI_DisableAutoSS(spi_base);
+        }
+    }
+    else {
+        // Slave
+        // Configure SS as low active.
+        spi_base->SSCTL &= ~SPI_SSCTL_SSACTPOL_Msk;
+        // NOTE: SPI_SS0 is defined as the slave select input in Slave mode.
+    }
+}
+
+void spi_frequency(spi_t *obj, int hz)
+{
+    SPI_T *spi_base = (SPI_T *) NU_MODBASE(obj->spi.spi);
+    
+    while (SPI_IS_BUSY(spi_base));
+    SPI_DISABLE(spi_base);
+    
+    SPI_SetBusClock((SPI_T *) NU_MODBASE(obj->spi.spi), hz);
+}
+
+
+int spi_master_write(spi_t *obj, int value)
+{
+    SPI_T *spi_base = (SPI_T *) NU_MODBASE(obj->spi.spi);
+    
+    // NOTE: Data in receive FIFO can be read out via ICE.
+    SPI_ENABLE(spi_base);
+    
+    // Wait for tx buffer empty
+    while(! spi_writeable(obj));
+    SPI_WRITE_TX(spi_base, value);
+
+    // Wait for rx buffer full
+    while (! spi_readable(obj));
+    int value2 = SPI_READ_RX(spi_base);
+    
+    SPI_DISABLE(spi_base);
+    
+    return value2;
+}
+
+#if DEVICE_SPISLAVE
+int spi_slave_receive(spi_t *obj)
+{
+    SPI_T *spi_base = (SPI_T *) NU_MODBASE(obj->spi.spi);
+    
+    SPI_ENABLE(spi_base);
+    
+    return spi_readable(obj);
+};
+
+int spi_slave_read(spi_t *obj)
+{
+    SPI_T *spi_base = (SPI_T *) NU_MODBASE(obj->spi.spi);
+    
+    SPI_ENABLE(spi_base);
+    
+    // Wait for rx buffer full
+    while (! spi_readable(obj));
+    int value = SPI_READ_RX(spi_base);
+    return value;
+}
+
+void spi_slave_write(spi_t *obj, int value)
+{
+    SPI_T *spi_base = (SPI_T *) NU_MODBASE(obj->spi.spi);
+    
+    SPI_ENABLE(spi_base);
+    
+    // Wait for tx buffer empty
+    while(! spi_writeable(obj));
+    SPI_WRITE_TX(spi_base, value);
+}
+#endif
+
+#if DEVICE_SPI_ASYNCH
+void spi_master_transfer(spi_t *obj, const void *tx, size_t tx_length, void *rx, size_t rx_length, uint8_t bit_width, uint32_t handler, uint32_t event, DMAUsage hint)
+{
+    //MBED_ASSERT(bits >= NU_SPI_FRAME_MIN && bits <= NU_SPI_FRAME_MAX);
+    SPI_T *spi_base = (SPI_T *) NU_MODBASE(obj->spi.spi);
+    SPI_SET_DATA_WIDTH(spi_base, bit_width);
+    
+    obj->spi.dma_usage = hint;
+    spi_check_dma_usage(&obj->spi.dma_usage, &obj->spi.dma_chn_id_tx, &obj->spi.dma_chn_id_rx);
+    uint32_t data_width = spi_get_data_width(obj);
+    // Conditions to go DMA way:
+    // (1) No DMA support for non-8 multiple data width.
+    // (2) tx length >= rx length. Otherwise, as tx DMA is done, no bus activity for remaining rx.
+    if ((data_width % 8) ||
+        (tx_length < rx_length)) {
+        obj->spi.dma_usage = DMA_USAGE_NEVER;
+        dma_channel_free(obj->spi.dma_chn_id_tx);
+        obj->spi.dma_chn_id_tx = DMA_ERROR_OUT_OF_CHANNELS;
+        dma_channel_free(obj->spi.dma_chn_id_rx);
+        obj->spi.dma_chn_id_rx = DMA_ERROR_OUT_OF_CHANNELS;
+    }
+    
+    // SPI IRQ is necessary for both interrupt way and DMA way
+    spi_enable_event(obj, event, 1);
+    spi_buffer_set(obj, tx, tx_length, rx, rx_length);
+            
+    SPI_ENABLE(spi_base);
+    
+    if (obj->spi.dma_usage == DMA_USAGE_NEVER) {
+        // Interrupt way
+        spi_master_write_asynch(obj, NU_SPI_FIFO_DEPTH / 2);
+        spi_enable_vector_interrupt(obj, handler, 1);
+        spi_master_enable_interrupt(obj, 1);
+    } else {
+        // DMA way
+        const struct nu_modinit_s *modinit = get_modinit(obj->spi.spi, spi_modinit_tab);
+        MBED_ASSERT(modinit != NULL);
+        MBED_ASSERT(modinit->modname == obj->spi.spi);
+    
+        // Configure tx DMA
+        PDMA->CHCTL |= 1 << obj->spi.dma_chn_id_tx;  // Enable this DMA channel
+        PDMA_SetTransferMode(obj->spi.dma_chn_id_tx,
+            ((struct nu_spi_var *) modinit->var)->pdma_perp_tx,    // Peripheral connected to this PDMA
+            0,  // Scatter-gather disabled
+            0); // Scatter-gather descriptor address
+        PDMA_SetTransferCnt(obj->spi.dma_chn_id_tx, 
+            (data_width == 8) ? PDMA_WIDTH_8 : (data_width == 16) ? PDMA_WIDTH_16 : PDMA_WIDTH_32, 
+            tx_length);
+        PDMA_SetTransferAddr(obj->spi.dma_chn_id_tx, 
+            ((uint32_t) tx) + (data_width / 8) * tx_length,   // NOTE: End of source address
+            PDMA_SAR_INC,   // Source address incremental
+            (uint32_t) &spi_base->TX,   // Destination address
+            PDMA_DAR_FIX);  // Destination address fixed
+        PDMA_SetBurstType(obj->spi.dma_chn_id_tx, 
+            PDMA_REQ_SINGLE,    // Single mode
+            0); // Burst size
+        PDMA_EnableInt(obj->spi.dma_chn_id_tx,
+            0); // Interrupt type. No use here
+        // Register DMA event handler
+        dma_set_handler(obj->spi.dma_chn_id_tx, (uint32_t) spi_dma_handler_tx, (uint32_t) obj, DMA_EVENT_ALL);
+        
+        // Configure rx DMA
+        PDMA->CHCTL |= 1 << obj->spi.dma_chn_id_rx;  // Enable this DMA channel
+        PDMA_SetTransferMode(obj->spi.dma_chn_id_rx,
+            ((struct nu_spi_var *) modinit->var)->pdma_perp_rx,    // Peripheral connected to this PDMA
+            0,  // Scatter-gather disabled
+            0); // Scatter-gather descriptor address
+        PDMA_SetTransferCnt(obj->spi.dma_chn_id_rx, 
+            (data_width == 8) ? PDMA_WIDTH_8 : (data_width == 16) ? PDMA_WIDTH_16 : PDMA_WIDTH_32, 
+            rx_length);
+        PDMA_SetTransferAddr(obj->spi.dma_chn_id_rx,
+            (uint32_t) &spi_base->RX,   // Source address
+            PDMA_SAR_FIX,   // Source address fixed
+            ((uint32_t) rx) + (data_width / 8) * rx_length,   // NOTE: End of destination address
+            PDMA_DAR_INC);  // Destination address incremental
+        PDMA_SetBurstType(obj->spi.dma_chn_id_rx, 
+            PDMA_REQ_SINGLE,    // Single mode
+            0); // Burst size
+        PDMA_EnableInt(obj->spi.dma_chn_id_rx,
+            0); // Interrupt type. No use here
+        // Register DMA event handler
+        dma_set_handler(obj->spi.dma_chn_id_rx, (uint32_t) spi_dma_handler_rx, (uint32_t) obj, DMA_EVENT_ALL);
+        
+        // Start tx/rx DMA transfer
+        spi_enable_vector_interrupt(obj, handler, 1);
+        // NOTE: It is safer to start rx DMA first and then tx DMA. Otherwise, receive FIFO is subject to overflow by tx DMA.
+        SPI_TRIGGER_RX_PDMA(((SPI_T *) NU_MODBASE(obj->spi.spi)));
+        SPI_TRIGGER_TX_PDMA(((SPI_T *) NU_MODBASE(obj->spi.spi)));
+        spi_master_enable_interrupt(obj, 1);
+    }
+}
+
+/**
+ * Abort an SPI transfer
+ * This is a helper function for event handling. When any of the events listed occurs, the HAL will abort any ongoing
+ * transfers
+ * @param[in] obj The SPI peripheral to stop
+ */
+void spi_abort_asynch(spi_t *obj)
+{
+    SPI_T *spi_base = (SPI_T *) NU_MODBASE(obj->spi.spi);
+    
+    if (obj->spi.dma_usage != DMA_USAGE_NEVER) {
+        // Receive FIFO Overrun in case of tx length > rx length on DMA way
+        if (spi_base->STATUS & SPI_STATUS_RXOVIF_Msk) {
+            spi_base->STATUS = SPI_STATUS_RXOVIF_Msk;
+        }
+        
+        if (obj->spi.dma_chn_id_tx != DMA_ERROR_OUT_OF_CHANNELS) {
+            PDMA_DisableInt(obj->spi.dma_chn_id_tx, 0);
+            // FIXME: Next PDMA transfer will fail with PDMA_STOP() called. Cause is unknown.
+            //PDMA_STOP(obj->spi.dma_chn_id_tx);
+            PDMA->CHCTL &= ~(1 << obj->spi.dma_chn_id_tx);
+        }
+        SPI_DISABLE_TX_PDMA(((SPI_T *) NU_MODBASE(obj->spi.spi)));
+        
+        if (obj->spi.dma_chn_id_rx != DMA_ERROR_OUT_OF_CHANNELS) {
+            PDMA_DisableInt(obj->spi.dma_chn_id_rx, 0);
+            // FIXME: Next PDMA transfer will fail with PDMA_STOP() called. Cause is unknown.
+            //PDMA_STOP(obj->spi.dma_chn_id_rx);
+            PDMA->CHCTL &= ~(1 << obj->spi.dma_chn_id_rx);
+        }
+        SPI_DISABLE_RX_PDMA(((SPI_T *) NU_MODBASE(obj->spi.spi)));
+    }
+    
+    // Necessary for both interrupt way and DMA way
+    spi_enable_vector_interrupt(obj, 0, 0);
+    spi_master_enable_interrupt(obj, 0);
+    
+    // FIXME: SPI H/W may get out of state without the busy check.
+    while (SPI_IS_BUSY(spi_base));
+    SPI_DISABLE(spi_base);
+    
+    SPI_ClearRxFIFO(spi_base);
+    SPI_ClearTxFIFO(spi_base);
+}
+
+/**
+ * Handle the SPI interrupt
+ * Read frames until the RX FIFO is empty.  Write at most as many frames as were read.  This way,
+ * it is unlikely that the RX FIFO will overflow.
+ * @param[in] obj The SPI peripheral that generated the interrupt
+ * @return
+ */
+uint32_t spi_irq_handler_asynch(spi_t *obj)
+{
+    // Check for SPI events
+    uint32_t event = spi_event_check(obj);
+    if (event) {
+        spi_abort_asynch(obj);
+    }
+
+    return (obj->spi.event & event) | ((event & SPI_EVENT_COMPLETE) ? SPI_EVENT_INTERNAL_TRANSFER_COMPLETE : 0);
+}
+
+uint8_t spi_active(spi_t *obj)
+{
+    SPI_T *spi_base = (SPI_T *) NU_MODBASE(obj->spi.spi);
+    // FIXME
+    /*
+    if ((obj->rx_buff.buffer && obj->rx_buff.pos < obj->rx_buff.length)
+            || (obj->tx_buff.buffer && obj->tx_buff.pos < obj->tx_buff.length) ){
+        return 1;
+    } else  {
+        // interrupts are disabled, all transaction have been completed
+        // TODO: checking rx fifo, it reports data eventhough RFDF is not set
+        return DSPI_HAL_GetIntMode(obj->spi.address, kDspiRxFifoDrainRequest);
+    }*/
+    
+    //return SPI_IS_BUSY(spi_base);
+    return (spi_base->CTL & SPI_CTL_SPIEN_Msk);
+}
+
+int spi_allow_powerdown(void)
+{
+    uint32_t modinit_mask = spi_modinit_mask;
+    while (modinit_mask) {
+        int spi_idx = nu_ctz(modinit_mask);
+        const struct nu_modinit_s *modinit = spi_modinit_tab + spi_idx;
+        if (modinit->modname != NC) {
+            SPI_T *spi_base = (SPI_T *) NU_MODBASE(modinit->modname);
+            // Disallow entering power-down mode if SPI transfer is enabled.
+            if (spi_base->CTL & SPI_CTL_SPIEN_Msk) {
+                return 0;
+            }
+        }
+        modinit_mask &= ~(1 << spi_idx);
+    }
+    
+    return 1;
+}
+
+static int spi_writeable(spi_t * obj)
+{
+    // Receive FIFO must not be full to avoid receive FIFO overflow on next transmit/receive
+    //return (! SPI_GET_TX_FIFO_FULL_FLAG(((SPI_T *) NU_MODBASE(obj->spi.spi)))) && (SPI_GET_RX_FIFO_COUNT(((SPI_T *) NU_MODBASE(obj->spi.spi))) < NU_SPI_FIFO_DEPTH);
+    return (! SPI_GET_TX_FIFO_FULL_FLAG(((SPI_T *) NU_MODBASE(obj->spi.spi))));
+}
+
+static int spi_readable(spi_t * obj)
+{
+    return ! SPI_GET_RX_FIFO_EMPTY_FLAG(((SPI_T *) NU_MODBASE(obj->spi.spi)));
+}
+
+static void spi_enable_event(spi_t *obj, uint32_t event, uint8_t enable)
+{   
+    obj->spi.event &= ~SPI_EVENT_ALL;
+    obj->spi.event |= (event & SPI_EVENT_ALL);
+    if (event & SPI_EVENT_RX_OVERFLOW) {
+        SPI_EnableInt((SPI_T *) NU_MODBASE(obj->spi.spi), SPI_FIFO_RXOVIEN_MASK);
+    }
+}
+
+static void spi_enable_vector_interrupt(spi_t *obj, uint32_t handler, uint8_t enable)
+{
+    const struct nu_modinit_s *modinit = get_modinit(obj->spi.spi, spi_modinit_tab);
+    MBED_ASSERT(modinit != NULL);
+    MBED_ASSERT(modinit->modname == obj->spi.spi);
+    
+    if (enable) {
+        NVIC_SetVector(modinit->irq_n, handler);
+        NVIC_EnableIRQ(modinit->irq_n);
+    }
+    else {
+        //NVIC_SetVector(modinit->irq_n, handler);
+        NVIC_DisableIRQ(modinit->irq_n);
+    }
+}
+
+static void spi_master_enable_interrupt(spi_t *obj, uint8_t enable)
+{   
+    SPI_T *spi_base = (SPI_T *) NU_MODBASE(obj->spi.spi);
+    
+    if (enable) {
+        SPI_SetFIFOThreshold(spi_base, 4, 4);
+        //SPI_SET_SUSPEND_CYCLE(spi_base, 4);
+        // Enable tx/rx FIFO threshold interrupt
+        SPI_EnableInt(spi_base, SPI_FIFO_RXTHIEN_MASK | SPI_FIFO_TXTHIEN_MASK);
+    }
+    else {
+        SPI_DisableInt(spi_base, SPI_FIFO_RXTHIEN_MASK | SPI_FIFO_TXTHIEN_MASK);
+    }
+}
+
+static uint32_t spi_event_check(spi_t *obj)
+{
+    SPI_T *spi_base = (SPI_T *) NU_MODBASE(obj->spi.spi);
+    uint32_t event = 0;
+    
+    if (obj->spi.dma_usage == DMA_USAGE_NEVER) {
+        uint32_t n_rec = spi_master_read_asynch(obj);
+        spi_master_write_asynch(obj, n_rec);
+    }
+    
+    if (spi_is_tx_complete(obj) && spi_is_rx_complete(obj)) {
+        event |= SPI_EVENT_COMPLETE;
+    }
+    
+    // Receive FIFO Overrun
+    if (spi_base->STATUS & SPI_STATUS_RXOVIF_Msk) {
+        spi_base->STATUS = SPI_STATUS_RXOVIF_Msk;
+        // In case of tx length > rx length on DMA way
+        if (obj->spi.dma_usage == DMA_USAGE_NEVER) {
+            event |= SPI_EVENT_RX_OVERFLOW;
+        }
+    }
+    
+    // Receive Time-Out
+    if (spi_base->STATUS & SPI_STATUS_RXTOIF_Msk) {
+        spi_base->STATUS = SPI_STATUS_RXTOIF_Msk;
+        //event |= SPI_EVENT_ERROR;
+    }
+    // Transmit FIFO Under-Run
+    if (spi_base->STATUS & SPI_STATUS_TXUFIF_Msk) {
+        spi_base->STATUS = SPI_STATUS_TXUFIF_Msk;
+        event |= SPI_EVENT_ERROR;
+    }
+    
+    return event;
+}
+
+/**
+ * Send words from the SPI TX buffer until the send limit is reached or the TX FIFO is full
+ * tx_limit is provided to ensure that the number of SPI frames (words) in flight can be managed.
+ * @param[in] obj       The SPI object on which to operate
+ * @param[in] tx_limit  The maximum number of words to send
+ * @return The number of SPI words that have been transfered
+ */
+static uint32_t spi_master_write_asynch(spi_t *obj, uint32_t tx_limit)
+{
+    uint32_t n_words = 0;
+    uint32_t tx_rmn = obj->tx_buff.length - obj->tx_buff.pos;
+    uint32_t rx_rmn = obj->rx_buff.length - obj->rx_buff.pos;
+    uint32_t max_tx = NU_MAX(tx_rmn, rx_rmn);
+    max_tx = NU_MIN(max_tx, tx_limit);
+    uint8_t data_width = spi_get_data_width(obj);
+    uint8_t bytes_per_word = (data_width + 7) / 8;
+    uint8_t *tx = (uint8_t *)(obj->tx_buff.buffer) + bytes_per_word * obj->tx_buff.pos;
+    SPI_T *spi_base = (SPI_T *) NU_MODBASE(obj->spi.spi);
+    
+    while ((n_words < max_tx) && spi_writeable(obj)) {
+        if (spi_is_tx_complete(obj)) {
+            // Transmit dummy as transmit buffer is empty
+            SPI_WRITE_TX(spi_base, 0);
+        }
+        else {
+            switch (bytes_per_word) {
+                case 4:
+                    SPI_WRITE_TX(spi_base, nu_get32_le(tx));
+                    tx += 4;
+                    break;
+                case 2:
+                    SPI_WRITE_TX(spi_base, nu_get16_le(tx));
+                    tx += 2;
+                    break;
+                case 1:
+                    SPI_WRITE_TX(spi_base, *((uint8_t *) tx));
+                    tx += 1;
+                    break;
+            }
+        
+            obj->tx_buff.pos ++;
+        }
+        n_words ++;
+    }
+    
+    //Return the number of words that have been sent
+    return n_words;
+}
+
+/**
+ * Read SPI words out of the RX FIFO
+ * Continues reading words out of the RX FIFO until the following condition is met:
+ * o There are no more words in the FIFO
+ * OR BOTH OF:
+ * o At least as many words as the TX buffer have been received
+ * o At least as many words as the RX buffer have been received
+ * This way, RX overflows are not generated when the TX buffer size exceeds the RX buffer size
+ * @param[in] obj The SPI object on which to operate
+ * @return Returns the number of words extracted from the RX FIFO
+ */
+static uint32_t spi_master_read_asynch(spi_t *obj)
+{
+    uint32_t n_words = 0;
+    uint32_t tx_rmn = obj->tx_buff.length - obj->tx_buff.pos;
+    uint32_t rx_rmn = obj->rx_buff.length - obj->rx_buff.pos;
+    uint32_t max_rx = NU_MAX(tx_rmn, rx_rmn);
+    uint8_t data_width = spi_get_data_width(obj);
+    uint8_t bytes_per_word = (data_width + 7) / 8;
+    uint8_t *rx = (uint8_t *)(obj->rx_buff.buffer) + bytes_per_word * obj->rx_buff.pos;
+    SPI_T *spi_base = (SPI_T *) NU_MODBASE(obj->spi.spi);
+    
+    while ((n_words < max_rx) && spi_readable(obj)) {
+        if (spi_is_rx_complete(obj)) {
+            // Disregard as receive buffer is full
+            SPI_READ_RX(spi_base);
+        }
+        else {
+            switch (bytes_per_word) {
+                case 4: {
+                    uint32_t val = SPI_READ_RX(spi_base);
+                    nu_set32_le(rx, val);
+                    rx += 4;
+                    break;
+                }
+                case 2: {
+                    uint16_t val = SPI_READ_RX(spi_base);
+                    nu_set16_le(rx, val);
+                    rx += 2;
+                    break;
+                }
+                case 1:
+                    *rx ++ = SPI_READ_RX(spi_base);
+                    break;
+            }
+        
+            obj->rx_buff.pos ++;
+        }
+        n_words ++;
+    }
+    
+    // Return the number of words received
+    return n_words;
+}
+
+static void spi_buffer_set(spi_t *obj, const void *tx, size_t tx_length, void *rx, size_t rx_length)
+{
+    obj->tx_buff.buffer = (void *) tx;
+    obj->tx_buff.length = tx_length;
+    obj->tx_buff.pos = 0;
+    obj->tx_buff.width = spi_get_data_width(obj);
+    obj->rx_buff.buffer = rx;
+    obj->rx_buff.length = rx_length;
+    obj->rx_buff.pos = 0;
+    obj->rx_buff.width = spi_get_data_width(obj);
+}
+
+static void spi_check_dma_usage(DMAUsage *dma_usage, int *dma_ch_tx, int *dma_ch_rx)
+{
+    if (*dma_usage != DMA_USAGE_NEVER) {
+        if (*dma_ch_tx == DMA_ERROR_OUT_OF_CHANNELS) {
+            *dma_ch_tx = dma_channel_allocate(DMA_CAP_NONE);
+        }
+        if (*dma_ch_rx == DMA_ERROR_OUT_OF_CHANNELS) {
+            *dma_ch_rx = dma_channel_allocate(DMA_CAP_NONE);
+        }
+        
+        if (*dma_ch_tx == DMA_ERROR_OUT_OF_CHANNELS || *dma_ch_rx == DMA_ERROR_OUT_OF_CHANNELS) {
+            *dma_usage = DMA_USAGE_NEVER;
+        }
+    }
+    
+    if (*dma_usage == DMA_USAGE_NEVER) {
+        dma_channel_free(*dma_ch_tx);
+        *dma_ch_tx = DMA_ERROR_OUT_OF_CHANNELS;
+        dma_channel_free(*dma_ch_rx);
+        *dma_ch_rx = DMA_ERROR_OUT_OF_CHANNELS;
+    }
+}
+
+static uint8_t spi_get_data_width(spi_t *obj)
+{    
+    SPI_T *spi_base = (SPI_T *) NU_MODBASE(obj->spi.spi);
+    
+    return ((spi_base->CTL & SPI_CTL_DWIDTH_Msk) >> SPI_CTL_DWIDTH_Pos);
+}
+
+static int spi_is_tx_complete(spi_t *obj)
+{
+    // ???: Exclude tx fifo empty check due to no such interrupt on DMA way
+    return (obj->tx_buff.pos == obj->tx_buff.length);
+    //return (obj->tx_buff.pos == obj->tx_buff.length && SPI_GET_TX_FIFO_EMPTY_FLAG(((SPI_T *) NU_MODBASE(obj->spi.spi))));
+}
+
+static int spi_is_rx_complete(spi_t *obj)
+{
+    return (obj->rx_buff.pos == obj->rx_buff.length);
+}
+
+static void spi_dma_handler_tx(uint32_t id, uint32_t event_dma)
+{
+    spi_t *obj = (spi_t *) id;
+    
+    // FIXME: Pass this error to caller
+    if (event_dma & DMA_EVENT_ABORT) {
+    }
+    // Expect SPI IRQ will catch this transfer done event
+    if (event_dma & DMA_EVENT_TRANSFER_DONE) {
+        obj->tx_buff.pos = obj->tx_buff.length;
+    }
+    // FIXME: Pass this error to caller
+    if (event_dma & DMA_EVENT_TIMEOUT) {
+    }
+    
+    const struct nu_modinit_s *modinit = get_modinit(obj->spi.spi, spi_modinit_tab);
+    MBED_ASSERT(modinit != NULL);
+    MBED_ASSERT(modinit->modname == obj->spi.spi);
+    
+    void (*vec)(void) = (void (*)(void)) NVIC_GetVector(modinit->irq_n);
+    vec();
+}
+
+static void spi_dma_handler_rx(uint32_t id, uint32_t event_dma)
+{
+    spi_t *obj = (spi_t *) id;
+    
+    // FIXME: Pass this error to caller
+    if (event_dma & DMA_EVENT_ABORT) {
+    }
+    // Expect SPI IRQ will catch this transfer done event
+    if (event_dma & DMA_EVENT_TRANSFER_DONE) {
+        obj->rx_buff.pos = obj->rx_buff.length;
+    }
+    // FIXME: Pass this error to caller
+    if (event_dma & DMA_EVENT_TIMEOUT) {
+    }
+    
+    const struct nu_modinit_s *modinit = get_modinit(obj->spi.spi, spi_modinit_tab);
+    MBED_ASSERT(modinit != NULL);
+    MBED_ASSERT(modinit->modname == obj->spi.spi);
+    
+    void (*vec)(void) = (void (*)(void)) NVIC_GetVector(modinit->irq_n);
+    vec();
+}
+
+#endif
+
+#endif