include/platform/nrf52/nrf52-dk.h

@@ -4,6 +4,7 @@
 #include "driver.h"
 
 #include "gpio.h"
+#include "spi.h"
 
 // LED 1
 const struct gpio nrf_led_1 = {
@@ -49,4 +50,15 @@ const struct driver led_4 = {
     .dev = &nrf_led_4
 };
 
+const struct spi nrf_spi_0 = {
+    .sck_pin = 2,
+    .mosi_pin = 3,
+    .miso_pin = 4
+};
+const struct driver spi_0 = {
+    .name = "SPI0",
+    .fp = &spi_fp,
+    .dev = &nrf_spi_0
+};
+
 #endif

include/spi.h

@@ -0,0 +1,18 @@
+int spi_open(const struct driver *drv);
+int spi_close(const struct driver *drv);
+
+int spi_write(const struct driver *drv, const char *buffer, unsigned int len);
+
+struct spi {
+    unsigned int sck_pin;
+    unsigned int mosi_pin;
+    unsigned int miso_pin;
+};
+
+static const struct driver_fp spi_fp = {
+    .open = spi_open,
+    .close = spi_close,
+    .read = NULL,
+    .write = spi_write,
+    .ioctl = NULL
+};

src/application/spi/main.c

@@ -1,43 +1,3 @@
-/**
- * Copyright (c) 2015 - 2019, Nordic Semiconductor ASA
- *
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without modification,
- * are permitted provided that the following conditions are met:
- *
- * 1. Redistributions of source code must retain the above copyright notice, this
- *    list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form, except as embedded into a Nordic
- *    Semiconductor ASA integrated circuit in a product or a software update for
- *    such product, must reproduce the above copyright notice, this list of
- *    conditions and the following disclaimer in the documentation and/or other
- *    materials provided with the distribution.
- *
- * 3. Neither the name of Nordic Semiconductor ASA nor the names of its
- *    contributors may be used to endorse or promote products derived from this
- *    software without specific prior written permission.
- *
- * 4. This software, with or without modification, must only be used with a
- *    Nordic Semiconductor ASA integrated circuit.
- *
- * 5. Any software provided in binary form under this license must not be reverse
- *    engineered, decompiled, modified and/or disassembled.
- *
- * THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS
- * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA OR CONTRIBUTORS BE
- * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
- * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
- * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
-#include "nrf_drv_spi.h"
 #include "app_util_platform.h"
 #include "nrf_gpio.h"
 #include "nrf_delay.h"
@@ -48,63 +8,29 @@
 #include "nrf_log_ctrl.h"
 #include "nrf_log_default_backends.h"
 
-#define SPI_INSTANCE  0 /**< SPI instance index. */
+#include "board.h"
-static const nrf_drv_spi_t spi = NRF_DRV_SPI_INSTANCE(SPI_INSTANCE);  /**< SPI instance. */
+#include "driver.h"
-static volatile bool spi_xfer_done;  /**< Flag used to indicate that SPI instance completed the transfer. */
 
-#define TEST_STRING "Nordic"
+const char buf[] = "Test";
-static uint8_t       m_tx_buf[] = TEST_STRING;           /**< TX buffer. */
-static uint8_t       m_rx_buf[sizeof(TEST_STRING) + 1];    /**< RX buffer. */
-static const uint8_t m_length = sizeof(m_tx_buf);        /**< Transfer length. */
-
-/**
- * @brief SPI user event handler.
- * @param event
- */
-void spi_event_handler(nrf_drv_spi_evt_t const * p_event,
-                       void *                    p_context)
-{
-    spi_xfer_done = true;
-    NRF_LOG_INFO("Transfer completed.");
-    if (m_rx_buf[0] != 0)
-    {
-        NRF_LOG_INFO(" Received:");
-        NRF_LOG_HEXDUMP_INFO(m_rx_buf, strlen((const char *)m_rx_buf));
-    }
-}
 
 int main(void)
 {
-    bsp_board_init(BSP_INIT_LEDS);
+    unsigned int cnt = 0;
-
     APP_ERROR_CHECK(NRF_LOG_INIT(NULL));
     NRF_LOG_DEFAULT_BACKENDS_INIT();
 
-    nrf_drv_spi_config_t spi_config = NRF_DRV_SPI_DEFAULT_CONFIG;
+    drv_open(&led_1);
-    spi_config.ss_pin   = SPI_SS_PIN;
+    drv_open(&spi_0);
-    spi_config.miso_pin = SPI_MISO_PIN;
-    spi_config.mosi_pin = SPI_MOSI_PIN;
-    spi_config.sck_pin  = SPI_SCK_PIN;
-    APP_ERROR_CHECK(nrf_drv_spi_init(&spi, &spi_config, spi_event_handler, NULL));
 
     NRF_LOG_INFO("SPI example started.");
 
-    while (1)
+    while(1) {
-    {
+        char c = (cnt++ % 2) + 0x30;
-        // Reset rx buffer and transfer done flag
+        drv_write(&led_1, &c, 1);
-        memset(m_rx_buf, 0, m_length);
+        drv_write(&spi_0, buf, sizeof(buf));
-        spi_xfer_done = false;
-
-        APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, m_tx_buf, m_length, m_rx_buf, m_length));
-
-        while (!spi_xfer_done)
-        {
-            __WFE();
-        }
 
         NRF_LOG_FLUSH();
 
-        bsp_board_led_invert(BSP_BOARD_LED_0);
         nrf_delay_ms(200);
     }
 }

src/platform/nrf52/spi.c

@@ -0,0 +1,62 @@
+#include <assert.h>
+#include <stddef.h>
+
+#include "nrf.h"
+
+#include "driver.h"
+#include "spi.h"
+
+static inline int spi_transfer(uint32_t t);
+
+
+int spi_open(const struct driver *drv)
+{
+    assert(NULL != drv);
+
+    struct spi *this = (struct spi *)drv->dev;
+
+    NRF_SPI0->ENABLE = 0;
+    NRF_SPI0->PSELSCK = this->sck_pin;
+    NRF_SPI0->PSELMOSI = this->mosi_pin;
+    NRF_SPI0->PSELMISO = this->miso_pin;
+    NRF_SPI0->FREQUENCY = SPI_FREQUENCY_FREQUENCY_M8;
+
+    NRF_SPI0->CONFIG = (0x03 << 1); //Sample on trailing edge of clock, shift serial data on leading edge, SCK polarity Active low
+    NRF_SPI0->EVENTS_READY = 0;
+    NRF_SPI0->ENABLE = (SPI_ENABLE_ENABLE_Enabled << SPI_ENABLE_ENABLE_Pos);
+
+    return 0;
+}
+
+int spi_close(const struct driver *drv)
+{
+    NRF_SPI0->ENABLE = 0;
+
+    return 0;
+}
+
+int spi_write(const struct driver *drv, const char *buffer, unsigned int len)
+{
+    assert(NULL != buffer);
+
+    //FIXME: missing CS handling
+
+    for(unsigned int i = 0; i < len; i++) {
+        spi_transfer(buffer[i]);
+    }
+
+    //FIXME: missing CS handling
+
+    return len;
+}
+
+static inline int spi_transfer(uint32_t t)
+{
+    volatile uint32_t r;
+    NRF_SPI0->EVENTS_READY = 0;           // ready
+    NRF_SPI0->TXD = t;          // out
+    while(NRF_SPI0->EVENTS_READY == 0) {
+    }
+    r = NRF_SPI0->RXD;                    // in
+    return (int)r;
+}