Published March 13, 2020 © CC0

IMX-RT Drum Pad

This is simple Drum Pad built with Cap-sense touch and IMX-RT.

IntermediateShowcase (no instructions)2 days1,099

Runner Ups

Crossover Code Challenge

Things used in this project

Hardware components

NXP IMX RT 1010 EVK

Boat Speaker

Power Bank

Aux cable

Cypress CY8CKIT-032 PSoC® Analog Front End Kit

Story

This Drum Pad is one of my old idea and wish too. I submitted this idea during "Sony Spresense" contest unfortunately I did not received the board. So the idea was lying on my head for over a year.

Finally its breaks out with the NXP's IMX RT Crossover MCU, I was having IMXRT1015 so initially I started the project with that, later I ported the code into IMXRT1011.

I used AFE shield board from Cypress, this can be seated on top of the IMX RT over Arduino connector. The board has PSoC4 analog processor (MUC) in it.

AFE shield has interfaces for OLED, Capsense, Switches and LED's and accessed through i2C interface.

IMX RT side, using SAI to play the audio file at 16KHZ. I have created 12 samples (.wav file) and the raw data is stored in the music file. Based on the capsense button press triggering the sound effect.

Speaker I used is from Boat, it has internal battery so only thing required is to feed the Aux input from IMXRT EVK.

I felt that, button sense over I2C bit slow due to that having the limitation of playing the music as faster. Anyway its just demonstration of my concept.

This drum has 3 modes of music set. The mode can be changed with the help of mechanical switch (push button). Also the volume can be controlled via Potentiometer.

The working video is here.

Code

Main

#include "board.h"
#include "fsl_debug_console.h"
#include "fsl_sai.h"
#include "music.h"
#include "afe_shield.h"
#include "fsl_codec_common.h"

#include "fsl_wm8960.h"
#include "pin_mux.h"
#include "clock_config.h"
#include "fsl_codec_adapter.h"
/*******************************************************************************
 * Definitions
 ******************************************************************************/
/* SAI instance and clock */
#define DEMO_CODEC_WM8960
#define DEMO_SAI SAI1
#define DEMO_SAI_CHANNEL (0)
#define DEMO_SAI_BITWIDTH (kSAI_WordWidth16bits)
//#define DEMO_SAI_IRQ SAI1_IRQn
//#define SAI_TxIRQHandler SAI1_IRQHandler

/* Select Audio/Video PLL (786.48 MHz) as sai1 clock source */
#define DEMO_SAI1_CLOCK_SOURCE_SELECT (2U)
/* Clock pre divider for sai1 clock source */
#define DEMO_SAI1_CLOCK_SOURCE_PRE_DIVIDER (0U)
/* Clock divider for sai1 clock source */
#define DEMO_SAI1_CLOCK_SOURCE_DIVIDER (63U)
/* Get frequency of sai1 clock */
#define DEMO_SAI_CLK_FREQ                                                        \
    (CLOCK_GetFreq(kCLOCK_AudioPllClk) / (DEMO_SAI1_CLOCK_SOURCE_DIVIDER + 1U) / \
     (DEMO_SAI1_CLOCK_SOURCE_PRE_DIVIDER + 1U))

/* I2C instance and clock */
#define DEMO_I2C LPI2C1

/* Select USB1 PLL (480 MHz) as master lpi2c clock source */
#define DEMO_LPI2C_CLOCK_SOURCE_SELECT (0U)
/* Clock divider for master lpi2c clock source */
#define DEMO_LPI2C_CLOCK_SOURCE_DIVIDER (5U)
/* Get frequency of lpi2c clock */
#define DEMO_I2C_CLK_FREQ ((CLOCK_GetFreq(kCLOCK_Usb1PllClk) / 8) / (DEMO_LPI2C_CLOCK_SOURCE_DIVIDER + 1U))

#define OVER_SAMPLE_RATE (384U)

#define DEMO_AUDIO_SAMPLE_RATE (kSAI_SampleRate16KHz)

#if (defined FSL_FEATURE_SAI_HAS_MCLKDIV_REGISTER && FSL_FEATURE_SAI_HAS_MCLKDIV_REGISTER) || \
    (defined FSL_FEATURE_PCC_HAS_SAI_DIVIDER && FSL_FEATURE_PCC_HAS_SAI_DIVIDER)
#define DEMO_AUDIO_MASTER_CLOCK OVER_SAMPLE_RATE *DEMO_AUDIO_SAMPLE_RATE
#else
#define DEMO_AUDIO_MASTER_CLOCK DEMO_SAI_CLK_FREQ
#endif
/* demo audio data channel */
#define DEMO_AUDIO_DATA_CHANNEL (2U)
/* demo audio bit width */
#define DEMO_AUDIO_BIT_WIDTH kSAI_WordWidth16bits

#ifndef DEMO_SAI_TX_SYNC_MODE
#define DEMO_SAI_TX_SYNC_MODE kSAI_ModeAsync
#endif
#ifndef DEMO_SAI_RX_SYNC_MODE
#define DEMO_SAI_RX_SYNC_MODE kSAI_ModeSync
#endif
/*******************************************************************************
 * Prototypes
 ******************************************************************************/

/*******************************************************************************
 * Variables
 ******************************************************************************/
sai_handle_t txHandle           = {0};
static volatile bool isFinished = false;
extern codec_config_t boardCodecConfig;
#if (defined(FSL_FEATURE_SAI_HAS_MCR) && (FSL_FEATURE_SAI_HAS_MCR)) || \
    (defined(FSL_FEATURE_SAI_HAS_MCLKDIV_REGISTER) && (FSL_FEATURE_SAI_HAS_MCLKDIV_REGISTER))
sai_master_clock_t mclkConfig = {
#if defined(FSL_FEATURE_SAI_HAS_MCR) && (FSL_FEATURE_SAI_HAS_MCR)
    .mclkOutputEnable = true,
#if !(defined(FSL_FEATURE_SAI_HAS_NO_MCR_MICS) && (FSL_FEATURE_SAI_HAS_NO_MCR_MICS))
    .mclkSource = kSAI_MclkSourceSysclk,
#endif
#endif
};
#endif
codec_handle_t codecHandle;
volatile uint8_t drum_play=1;
volatile uint32_t sample_count=0;
volatile uint32_t sample_count_inv=0;
volatile uint8_t capbutton_value;
volatile uint8_t swbutton_value;
volatile uint32_t pot_value;
volatile uint8_t capbutton_prev_value;
volatile uint8_t drum_array=0;

extern void IMX_RT_ProcessMusic();
/*******************************************************************************
 * Code
 ******************************************************************************/
wm8960_config_t wm8960Config = {
    .i2cConfig = {.codecI2CInstance = BOARD_CODEC_I2C_INSTANCE, .codecI2CSourceClock = BOARD_CODEC_I2C_CLOCK_FREQ},
    .route     = kWM8960_RoutePlaybackandRecord,
    .rightInputSource = kWM8960_InputDifferentialMicInput2,
    .playSource       = kWM8960_PlaySourceDAC,
    .slaveAddress     = WM8960_I2C_ADDR,
    .bus              = kWM8960_BusI2S,
    .format = {.mclk_HZ = 6144000U, .sampleRate = kWM8960_AudioSampleRate16KHz, .bitWidth = kWM8960_AudioBitWidth16bit},
    .master_slave = false,
};
codec_config_t boardCodecConfig = {.codecDevType = kCODEC_WM8960, .codecDevConfig = &wm8960Config};
/*
 * AUDIO PLL setting: Frequency = Fref * (DIV_SELECT + NUM / DENOM)
 *                              = 24 * (32 + 77/100)
 *                              = 786.48 MHz
 */
const clock_audio_pll_config_t audioPllConfig = {
    .loopDivider = 32,  /* PLL loop divider. Valid range for DIV_SELECT divider value: 27~54. */
    .postDivider = 1,   /* Divider after the PLL, should only be 1, 2, 4, 8, 16. */
    .numerator   = 77,  /* 30 bit numerator of fractional loop divider. */
    .denominator = 100, /* 30 bit denominator of fractional loop divider */
};

static void Delay(uint32_t dly){

	while(dly--);
}

void BOARD_EnableSaiMclkOutput(bool enable)
{
    if (enable)
    {
        IOMUXC_GPR->GPR1 |= IOMUXC_GPR_GPR1_SAI1_MCLK_DIR_MASK;
    }
    else
    {
        IOMUXC_GPR->GPR1 &= (~IOMUXC_GPR_GPR1_SAI1_MCLK_DIR_MASK);
    }
}

static void callback(I2S_Type *base, sai_handle_t *handle, status_t status, void *userData)
{
    isFinished = true;
}

/*!
 * @brief Main function
 */
int main(void)
{
    sai_transfer_t xfer;
    uint32_t temp = 0;
    sai_transceiver_t config;

    BOARD_ConfigMPU();
    BOARD_InitPins();
    BOARD_BootClockRUN();
    CLOCK_InitAudioPll(&audioPllConfig);
    BOARD_InitDebugConsole();

    /*Clock setting for LPI2C*/
    CLOCK_SetMux(kCLOCK_Lpi2cMux, DEMO_LPI2C_CLOCK_SOURCE_SELECT);
    CLOCK_SetDiv(kCLOCK_Lpi2cDiv, DEMO_LPI2C_CLOCK_SOURCE_DIVIDER);


    /*Clock setting for SAI1*/
    CLOCK_SetMux(kCLOCK_Sai1Mux, DEMO_SAI1_CLOCK_SOURCE_SELECT);
    CLOCK_SetDiv(kCLOCK_Sai1PreDiv, DEMO_SAI1_CLOCK_SOURCE_PRE_DIVIDER);
    CLOCK_SetDiv(kCLOCK_Sai1Div, DEMO_SAI1_CLOCK_SOURCE_DIVIDER);

    /*Enable MCLK clock*/
    BOARD_EnableSaiMclkOutput(true);

    PRINTF("Drum Pad started!\n\r");

    /* Set up i2c master to send data to slave*/

      I2C_Init();
      OLED_Init();

      OLED_Clear_Screen();

      OLED_Print_Screen1();

    /* SAI init */
    SAI_Init(DEMO_SAI);
    SAI_TransferTxCreateHandle(DEMO_SAI, &txHandle, callback, NULL);
    /* I2S mode configurations */
    SAI_GetClassicI2SConfig(&config, DEMO_AUDIO_BIT_WIDTH, kSAI_Stereo, kSAI_Channel0Mask);
    config.syncMode = DEMO_SAI_TX_SYNC_MODE;
    SAI_TransferTxSetConfig(DEMO_SAI, &txHandle, &config);

#if DEMO_SAI_RX_SYNC_MODE == kSAI_ModeAsync
    config.syncMode = DEMO_SAI_RX_SYNC_MODE;
    SAI_RxSetConfig(DEMO_SAI, &config);
    SAI_RxSetBitClockRate(DEMO_SAI, DEMO_AUDIO_MASTER_CLOCK, DEMO_AUDIO_SAMPLE_RATE, DEMO_AUDIO_BIT_WIDTH,
                          DEMO_AUDIO_DATA_CHANNEL);
#endif

    /* set bit clock divider */
    SAI_TxSetBitClockRate(DEMO_SAI, DEMO_AUDIO_MASTER_CLOCK, DEMO_AUDIO_SAMPLE_RATE, DEMO_AUDIO_BIT_WIDTH,
                          DEMO_AUDIO_DATA_CHANNEL);

    /* master clock configurations */
#if (defined(FSL_FEATURE_SAI_HAS_MCR) && (FSL_FEATURE_SAI_HAS_MCR)) || \
    (defined(FSL_FEATURE_SAI_HAS_MCLKDIV_REGISTER) && (FSL_FEATURE_SAI_HAS_MCLKDIV_REGISTER))
#if defined(FSL_FEATURE_SAI_HAS_MCLKDIV_REGISTER) && (FSL_FEATURE_SAI_HAS_MCLKDIV_REGISTER)
    mclkConfig.mclkHz          = DEMO_AUDIO_MASTER_CLOCK;
    mclkConfig.mclkSourceClkHz = DEMO_SAI_CLK_FREQ;
#endif
    SAI_SetMasterClockConfig(DEMO_SAI, &mclkConfig);
#endif

    /* Use default setting to init codec */
    CODEC_Init(&codecHandle, &boardCodecConfig);


    while (1)
    {

		AFE_ReadData();

		if(swbutton_value ==1 ){

			drum_array++;

			Delay(20000);
			if(drum_array>2) drum_array=0;
			Delay(20000);
		}

		PRINTF("CapSense CT Value= %d\n\r",capbutton_value);
	  PRINTF("CapSense PV Value= %d\n\r",capbutton_prev_value);

    IMX_RT_ProcessMusic();

    }

}