TUSS4470: Issues Initializing TUSS4470

Hi everyone,

I’m working on a project using the STM32F103RBT6 to interface with the TUSS4470. However, I’ve encountered several issues during the initialization process:

1. Unexpected Reset Values: The register values I read after powering on do not match the reset values specified in the TUSS4470 datasheet.
2. Write/Read Inconsistency: When I try to write to a register and read it back, the value does not update as expected.
3. Abnormal SDO Feedback: After writing to a register, the feedback on the SDO line appears incorrect.

Additional Notes:

• I’m using a custom-designed circuit board that I assembled using SMT (surface mount technology). I’ve tested two separate PCBs, and both show the same issues.
• My development environment is IAR Embedded Workbench 8.32.1.

Has anyone encountered similar issues with the TUSS4470? I would appreciate any advice on debugging or identifying potential causes.

Below are the code snippet and snipaste I am using for initialization and SPI communication. 

#include "TUSS4470.h"

uint16_t init_check_buffer[13] = {0};
uint16_t write_back[13] = {0};

static uint8_t calculateParity(uint8_t txbuffer[]);

void TUSS4470_init()
{
    TUSS4470_Write_Register(BPF_CONFIG_1, 0x0, &write_back[0]);
    TUSS4470_Write_Register(BPF_CONFIG_2, 0x0, &write_back[1]);
    TUSS4470_Write_Register(DEV_CTRL_1, 0x0, &write_back[2]);
    TUSS4470_Write_Register(DEV_CTRL_2, 0x0, &write_back[3]);
    TUSS4470_Write_Register(DEV_CTRL_3, 0x0, &write_back[4]);
    TUSS4470_Write_Register(VDRV_CTRL, 0x20, &write_back[5]);
    TUSS4470_Write_Register(ECHO_INT_CONFIG, 0x7, &write_back[6]);
    TUSS4470_Write_Register(ZC_CONFIG, 0x14, &write_back[7]);
    TUSS4470_Write_Register(BURST_PULSE, 0x1, &write_back[8]);
    TUSS4470_Write_Register(TOF_CONFIG, 0x0, &write_back[9]);
    TUSS4470_Write_Register(DEV_STAT, 0x0, &write_back[10]);
    TUSS4470_Write_Register(DEVICE_ID, 0xB9, &write_back[11]);
    TUSS4470_Write_Register(REV_ID, 0x2, &write_back[12]);

    HAL_Delay(500);
    TUSS4470_Read_Register(BPF_CONFIG_1, &init_check_buffer[0]);
    TUSS4470_Read_Register(BPF_CONFIG_2, &init_check_buffer[1]);
    TUSS4470_Read_Register(DEV_CTRL_1, &init_check_buffer[2]);
    TUSS4470_Read_Register(DEV_CTRL_2, &init_check_buffer[3]);
    TUSS4470_Read_Register(DEV_CTRL_3, &init_check_buffer[4]);
    TUSS4470_Read_Register(VDRV_CTRL, &init_check_buffer[5]);
    TUSS4470_Read_Register(ECHO_INT_CONFIG, &init_check_buffer[6]);
    TUSS4470_Read_Register(ZC_CONFIG, &init_check_buffer[7]);
    TUSS4470_Read_Register(BURST_PULSE, &init_check_buffer[8]);
    TUSS4470_Read_Register(TOF_CONFIG, &init_check_buffer[9]);
    TUSS4470_Read_Register(DEV_STAT, &init_check_buffer[10]);
    TUSS4470_Read_Register(DEVICE_ID, &init_check_buffer[11]);
    TUSS4470_Read_Register(REV_ID, &init_check_buffer[12]);
}

void TUSS4470_Read_Register(uint8_t regAddr, uint16_t *data)
{
    uint8_t txbuffer[2] = {0}; // SPI transmit buffer
    uint8_t rxbuffer[2] = {0}; // SPI receive buffer

    txbuffer[0] = 0x80 + ((regAddr & 0x3F) << 1); // High byte: RW bit + address bits
    txbuffer[1] = 0x00;                           // Low byte: always 0
    txbuffer[0] |= calculateParity(txbuffer);     // Add parity bit

    TUSS4470_CSN_LOW(); // Pull chip select low
    HAL_Delay(500);
    HAL_SPI_TransmitReceive(&hspi1, txbuffer, rxbuffer, 2, HAL_MAX_DELAY);
    HAL_Delay(500);
    TUSS4470_CSN_HIGH(); // Pull chip select high

    *data = (rxbuffer[0] << 8) | rxbuffer[1]; // Combine received bytes
}

void TUSS4470_Write_Register(uint8_t regAddr, uint8_t data, uint16_t *write_back)
{
    uint8_t txbuffer[2] = {0}; // SPI transmit buffer
    uint8_t rxbuffer[2] = {0}; // SPI receive buffer

    txbuffer[0] = (regAddr & 0x3F) << 1;      // High byte: address bits
    txbuffer[1] = data;                       // Low byte: data
    txbuffer[0] |= calculateParity(txbuffer); // Add parity bit

    TUSS4470_CSN_LOW(); // Pull chip select low
    HAL_Delay(500);
    HAL_SPI_TransmitReceive(&hspi1, txbuffer, rxbuffer, 2, HAL_MAX_DELAY);
    HAL_Delay(500);
    TUSS4470_CSN_HIGH(); // Pull chip select high

    *write_back = (rxbuffer[0] << 8) | rxbuffer[1]; // Combine received bytes
}

static uint8_t calculateParity(uint8_t txbuffer[])
{
    uint8_t parity = 0;
    for (int i = 0; i < 2; i++)
    {
        uint8_t byte = txbuffer[i];
        while (byte)
        {
            parity ^= (byte & 1);
            byte >>= 1;
        }
    }
    return parity; // Return calculated parity bit
}

Thank you in advance for your help!