Hi,
I have a doubt regarding buffer setting in SPIS.
In the SDK15 SPIS example, buffers are set using nrfx_spis_buffers_set(...) and it works perfectly.
I was wondering if it's possible to avoid the buffer_set cal, setting a fixed RAM region using, for example:
NRF_SPIS1->TXD.PTR = &my_data
NRF_SPIS1->TXD.MAXCNT = my_data_size
(my_data is updated periodically every 500us)
Does nrfx_spis_buffers_set have to be called for every SPI transaction or is there any alternative method?
Marco
If you want to re-use your tx/rx buffers then you only need to call nrfx_spis_buffers_set once during initialization. The SPIS will use whatever's in the RXD/TXD registers and it does not reset the register after a transaction is completed.
If you want to re-use your tx/rx buffers then you only need to call nrfx_spis_buffers_set once during initialization. The SPIS will use whatever's in the RXD/TXD registers and it does not reset the register after a transaction is completed.
Thank you haakonsh for your reply.
Starting from the SDK example I deleted the nrf_drv_spis_buffers_set row in while(1) and I made these attempts:
NRF_LOG_INFO("SPIS example");
nrf_drv_spis_config_t spis_config = NRF_DRV_SPIS_DEFAULT_CONFIG;
spis_config.csn_pin = APP_SPIS_CS_PIN;
spis_config.miso_pin = APP_SPIS_MISO_PIN;
spis_config.mosi_pin = APP_SPIS_MOSI_PIN;
spis_config.sck_pin = APP_SPIS_SCK_PIN;
APP_ERROR_CHECK(nrf_drv_spis_init(&spis, &spis_config, spis_event_handler));
nrf_drv_spis_buffers_set(&spis, m_tx_buf, m_length, m_rx_buf, m_length);
In this way the SPIS sends correctly only during the fist HITOLO transition of master chip select, then the MISO becomes HIGH and doesn't trasmit data anymore.
void spis_event_handler(nrf_drv_spis_event_t event)
{
if (event.evt_type == NRF_DRV_SPIS_XFER_DONE)
{
spis_xfer_done = true;
NRF_LOG_INFO(" Transfer completed. Received: %s",(uint32_t)m_rx_buf);
nrf_drv_spis_buffers_set(&spis, m_tx_buf, m_length, m_rx_buf, m_length);
}
}
In this way the SPIS works fine but I have to recall nrf_drv_spis_buffers_set for every transition.
I didn't change anything also from the example code, I report it for completeness:
/**
* Copyright (c) 2015 - 2018, 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 "sdk_config.h"
#include "nrf_drv_spis.h"
#include "nrf_gpio.h"
#include "boards.h"
#include "app_error.h"
#include <string.h>
#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"
#define SPIS_INSTANCE 1 /**< SPIS instance index. */
static const nrf_drv_spis_t spis = NRF_DRV_SPIS_INSTANCE(SPIS_INSTANCE);/**< SPIS instance. */
#define TEST_STRING "Nordic"
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. */
static volatile bool spis_xfer_done; /**< Flag used to indicate that SPIS instance completed the transfer. */
/**
* @brief SPIS user event handler.
*
* @param event
*/
void spis_event_handler(nrf_drv_spis_event_t event)
{
if (event.evt_type == NRF_DRV_SPIS_XFER_DONE)
{
spis_xfer_done = true;
NRF_LOG_INFO(" Transfer completed. Received: %s",(uint32_t)m_rx_buf);
nrf_drv_spis_buffers_set(&spis, m_tx_buf, m_length, m_rx_buf, m_length);
}
}
int main(void)
{
// Enable the constant latency sub power mode to minimize the time it takes
// for the SPIS peripheral to become active after the CSN line is asserted
// (when the CPU is in sleep mode).
NRF_POWER->TASKS_CONSTLAT = 1;
bsp_board_init(BSP_INIT_LEDS);
APP_ERROR_CHECK(NRF_LOG_INIT(NULL));
NRF_LOG_DEFAULT_BACKENDS_INIT();
NRF_LOG_INFO("SPIS example");
nrf_drv_spis_config_t spis_config = NRF_DRV_SPIS_DEFAULT_CONFIG;
spis_config.csn_pin = APP_SPIS_CS_PIN;
spis_config.miso_pin = APP_SPIS_MISO_PIN;
spis_config.mosi_pin = APP_SPIS_MOSI_PIN;
spis_config.sck_pin = APP_SPIS_SCK_PIN;
APP_ERROR_CHECK(nrf_drv_spis_init(&spis, &spis_config, spis_event_handler));
nrf_drv_spis_buffers_set(&spis, m_tx_buf, m_length, m_rx_buf, m_length);
while (1)
{
memset(m_rx_buf, 0, m_length);
spis_xfer_done = false;
// APP_ERROR_CHECK(nrf_drv_spis_buffers_set(&spis, m_tx_buf, m_length, m_rx_buf, m_length));
while (!spis_xfer_done)
{
__WFE();
}
NRF_LOG_FLUSH();
bsp_board_led_invert(BSP_BOARD_LED_0);
}
}
Did I make any mistake during the initialization?
I am connecting 2 nrf52832 boards. The SPI master works with the "spi" SDK example.