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#104 Angle Brick

Overview

ボリューム抵抗を使ったBrickです。

I/Oピンからアナログ値を取得することができます。

LED Brickの明るさを調節する際などに使用します。

Connecting

Schematic

Code explanation

nRF52832は、ADCが使えるピンは決まっており、P0.03は、AIN1となります。

アナログ値はターミナルソフト(Teratermなど)から確認しましょう。

ドライバはPPI（Programmable peripheral interconnect）ドライバを使います。A/D変換するの にARMコアを起動するのは消費電力の無駄であり、PPIという仕組みを利用して、PPIのチャンネルを指定 、コアを起動しないで、イベントメモリとタスクで計測データをPPIのメモリに保存します。

User Include Directories

Solution Option -> Preprocessor -> User Include Directoriesに以下を追加する。(../nRF5_SDKの部分は適宜変えてください。)

Path
../nRF5_SDK/modules/nrfx/drivers/src/prs
../nRF5_SDK/modules/nrfx/drivers/src
../nRF5_SDK/components/libraries/mutex
../nRF5_SDK/components/libraries/atomic
../nRF5_SDK/components/libraries/ringbuf
../nRF5_SDK/external/fprintf
../nRF5_SDK/components/libraries/strerror
../nRF5_SDK/components/libraries/balloc
../nRF5_SDK/components/libraries/memobj
../nRF5_SDK/components/libraries/log
../nRF5_SDK/components/libraries/experimental_section_vars
../nRF5_SDK/components/libraries/pwr_mgmt
../nRF5_SDK/components/libraries/delay
../nRF5_SDK/modules/nrfx/hal
../nRF5_SDK/components/boards
../nRF5_SDK/components/drivers_nrf/nrf_soc_nosd
../nRF5_SDK/components/libraries/util
../nRF5_SDK/integration/nrfx
../nRF5_SDK/modules/nrfx
../nRF5_SDK/modules/nrfx/drivers/include
../nRF5_SDK/integration/nrfx/legacy
../nRF5_SDK/components/toolchain/cmsis/include
../nRF5_SDK/modules/nrfx/mdk
.

Preprocessor Definitions

Solution Option -> Preprocessor -> Preprocessor Definitionsに以下を追加する。

COPT
SAADC_ENABLED
PPI_ENABLED
POWER_ENABLED
TIMER0_ENABLED
TIMER_ENABLED
NRFX_SAADC_ENABLED
NRFX_PPI_ENABLED
NRFX_POWER_ENABLED
NRFX_TIMER0_ENABLED
NRFX_TIMER_ENABLED
BOARD_CUSTOM
NRF52832_XXAB
DEBUG

SDK File

Projectに以下のファイルを追加する。(../nRF5_SDKの部分は適宜変えてください。)

File Path
app_error_handler_gcc.c ../nRF5_SDK/components/libraries/util
app_error_weak.c ../nRF5_SDK/components/libraries/util
app_error.c ../nRF5_SDK/components/libraries/util
app_util_platform.c ../nRF5_SDK/components/libraries/util
nrf_atomic.c ../nRF5_SDK/components/libraries/atomic
nrf_balloc.c ../nRF5_SDK/components/libraries/balloc
nrf_drv_power.c ../nRF5_SDK/integration/nrfx/legacy
nrf_drv_ppi.c ../nRF5_SDK/integration/nrfx/legacy
nrf_drv_uart.c ../nRF5_SDK/integration/nrfx/legacy
nrf_fprintf_format.c ../nRF5_SDK/external/fprintf
nrf_fprintf.c ../nRF5_SDK/external/fprintf
nrf_log_backend_serial.c ../nRF5_SDK/components/libraries/log/src
nrf_log_backend_uart.c ../nRF5_SDK/components/libraries/log/src
nrf_log_default_backends.c ../nRF5_SDK/components/libraries/log/src
nrf_log_frontend.c ../nRF5_SDK/components/libraries/log/src
nrf_log_str_formatter.c ../nRF5_SDK/components/libraries/log/src
nrf_memobj.c ../nRF5_SDK/components/libraries/memobj
nrf_pwr_mgmt.c ../nRF5_SDK/components/libraries/pwr_mgmt
nrf_ringbuf.c ../nRF5_SDK/components/libraries/ringbuf
nrf_section_iter.c ../nRF5_SDK/components/libraries/experimental_section_vars
nrf_strerror.c ../nRF5_SDK/components/libraries/strerror
nrfx_power.c ../nRF5_SDK/modules/nrfx/drivers/src
nrfx_ppi.c ../nRF5_SDK/modules/nrfx/drivers/src
nrfx_prs.c ../nRF5_SDK/modules/nrfx/drivers/src/prs
nrfx_saadc.c ../nRF5_SDK/modules/nrfx/drivers/src
nrfx_timer.c ../nRF5_SDK/modules/nrfx/drivers/src
nrfx_uart.c ../nRF5_SDK/modules/nrfx/drivers/src
nrfx_uarte.c ../nRF5_SDK/modules/nrfx/drivers/src

Section

SEGGER_Flash.icfファイルを編集する。(SEGGER_Flash.icfはProject配下に自動生成されている。以下抜粋)

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 :

define block log_const_data_start with size = 8 { symbol __start_log_const_data };
define block log_const_data_list { section .log_const_data* };
define block log_const_data_stop with size = 8 { symbol __stop_log_const_data };
define block log_const_data with fixed order { block log_const_data_start, block log_const_data_list, block log_const_data_stop };

 :

place in FLASH                           {
                                           block tdata_load,                       // Thread-local-storage load image
                                           section .log_backends,
                                           section .nrf_balloc,
                                           block log_const_data
                                         };
 :

IRQHandler

Cortex_M_Startup.sファイルを編集する。(長いので抜粋)

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ISR_HANDLER ExternalISR0
ISR_HANDLER ExternalISR1
ISR_HANDLER UARTE0_UART0_IRQHandler //ExternalISR2
ISR_HANDLER ExternalISR3
ISR_HANDLER ExternalISR4
ISR_HANDLER ExternalISR5
ISR_HANDLER ExternalISR6
ISR_HANDLER SAADC_IRQHandler        //ExternalISR7
ISR_HANDLER ExternalISR8
ISR_HANDLER ExternalISR9
ISR_HANDLER ExternalISR10

Sample Code

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#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include "nrf.h"
#include "nrf_drv_saadc.h"
#include "nrf_drv_ppi.h"
#include "nrf_drv_timer.h"
#include "boards.h"
#include "app_error.h"
#include "nrf_delay.h"
#include "app_util_platform.h"
#include "nrf_pwr_mgmt.h"
#include "nrf_drv_power.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"
#define NRF_LOG_MODULE_NAME FABO_104_ANGLE
#include "nrf_log.h"
NRF_LOG_MODULE_REGISTER();

#define SAMPLES_IN_BUFFER 10
volatile uint8_t state = 1;

static const nrf_drv_timer_t m_timer = NRF_DRV_TIMER_INSTANCE(0);
static nrf_saadc_value_t     m_buffer_pool[2][SAMPLES_IN_BUFFER];
static nrf_ppi_channel_t     m_ppi_channel;
static uint32_t              m_adc_evt_counter;

nrf_log_module_const_data_t*    __start_log_const_data;
nrf_log_module_dynamic_data_t*  __start_log_dynamic_data;
void*                           __start_pwr_mgmt_data;
void*                           __stop_log_const_data;
void*                           __stop_log_dynamic_data;
void*                           __stop_pwr_mgmt_data;

void timer_handler(nrf_timer_event_t event_type, void * p_context)
{

}

void saadc_sampling_event_init(void)
{
    ret_code_t err_code;

    err_code = nrf_drv_ppi_init();
    APP_ERROR_CHECK(err_code);

    nrf_drv_timer_config_t timer_cfg = NRF_DRV_TIMER_DEFAULT_CONFIG;
    timer_cfg.bit_width = NRF_TIMER_BIT_WIDTH_32;
    err_code = nrf_drv_timer_init(&m_timer, &timer_cfg, timer_handler);
    APP_ERROR_CHECK(err_code);

    uint32_t ticks = nrf_drv_timer_ms_to_ticks(&m_timer, 100);
    nrf_drv_timer_extended_compare(&m_timer,
                                   NRF_TIMER_CC_CHANNEL0,
                                   ticks,
                                   NRF_TIMER_SHORT_COMPARE0_CLEAR_MASK,
                                   false);
    nrf_drv_timer_enable(&m_timer);

    uint32_t timer_compare_event_addr = nrf_drv_timer_compare_event_address_get(&m_timer,
                                                                                NRF_TIMER_CC_CHANNEL0);
    uint32_t saadc_sample_task_addr   = nrf_drv_saadc_sample_task_get();

    /* setup ppi channel so that timer compare event is triggering sample task in SAADC */
    err_code = nrf_drv_ppi_channel_alloc(&m_ppi_channel);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_drv_ppi_channel_assign(m_ppi_channel,
                                          timer_compare_event_addr,
                                          saadc_sample_task_addr);
    APP_ERROR_CHECK(err_code);
}


void saadc_sampling_event_enable(void)
{
    ret_code_t err_code = nrf_drv_ppi_channel_enable(m_ppi_channel);

    APP_ERROR_CHECK(err_code);
}


void saadc_callback(nrf_drv_saadc_evt_t const * p_event)
{
    if (p_event->type == NRF_DRV_SAADC_EVT_DONE)
    {
        ret_code_t err_code;

        err_code = nrf_drv_saadc_buffer_convert(p_event->data.done.p_buffer, SAMPLES_IN_BUFFER);
        APP_ERROR_CHECK(err_code);

        int i;
        NRF_LOG_INFO("ADC event number: %d", (int)m_adc_evt_counter);

        for (i = 0; i < SAMPLES_IN_BUFFER; i++)
        {
            NRF_LOG_INFO("%d", p_event->data.done.p_buffer[i]);
        }
        m_adc_evt_counter++;
    }
}


void saadc_init(void)
{
    ret_code_t err_code;
    nrf_saadc_channel_config_t channel_config =
        NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN1);

    err_code = nrf_drv_saadc_init(NULL, saadc_callback);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_drv_saadc_channel_init(0, &channel_config);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_drv_saadc_buffer_convert(m_buffer_pool[0], SAMPLES_IN_BUFFER);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_drv_saadc_buffer_convert(m_buffer_pool[1], SAMPLES_IN_BUFFER);
    APP_ERROR_CHECK(err_code);

}

int main(void)
{
    APP_ERROR_CHECK(NRF_LOG_INIT(NULL));
    NRF_LOG_DEFAULT_BACKENDS_INIT();

    APP_ERROR_CHECK(nrf_drv_power_init(NULL));

    APP_ERROR_CHECK(nrf_pwr_mgmt_init());

    NRF_LOG_INFO("Fabo Shinobi Sample Angle Brick 104");

    saadc_init();
    saadc_sampling_event_init();
    saadc_sampling_event_enable();

    while (1)
    {
        nrf_pwr_mgmt_run();
        NRF_LOG_FLUSH();
    }
}

構成Parts

  • ボリューム抵抗器A 10k

GitHub