ksz8895.c

////////////////////////////////////////////////////////////////////////////////
/// @file
/// @brief KSZ8895 Ethernet switch.
////////////////////////////////////////////////////////////////////////////////

// *****************************************************************************
// ************************** System Include Files *****************************
// *****************************************************************************

// *****************************************************************************
// ************************** User Include Files *******************************
// *****************************************************************************

#include "tcpip/tcpip.h"
#include "ksz8895.h"
#include "softspi.h"

// *****************************************************************************
// ************************** Macros *******************************************
// *****************************************************************************

// *****************************************************************************
// ************************** Defines ******************************************
// *****************************************************************************

// *****************************************************************************
// ************************** Definitions **************************************
// *****************************************************************************

// *****************************************************************************
// ************************** Function Prototypes ******************************
// *****************************************************************************

// *****************************************************************************
// ************************** Global Functions *********************************
// *****************************************************************************

int KSZ8895Init( void )
{
    uint8_t readData;

    // Read chip family ID to verify SPI bus functionality. ---------
    do {
        // Read contents of register 0x00.
        while (KSZ8895ReadReg(0x00, &readData) != 0);
    }
    while (readData != 0x95);

    // Write/Read/Verify the start switch bit. ----------------------
    do {
        // Write "Start Switch" bit to register 0x01.
        while (KSZ8895WriteReg(0x01, 0x01) != 0);
        // Read contents of register 0x01.
        while (KSZ8895ReadReg(0x01, &readData) != 0);
    }
    while ((readData & 0x01) != 0x01);   // Verify "Start Switch" bit is set.

    return 0;
}

//==============================================================================

int KSZ8895ReadReg(uint8_t address, uint8_t *data)
{
    uint32_t rxData;
    
    SOFTSPI_TRANSFER readCmd =
    {
        .dev = SOFTSPI_KSZ8895,
        .txDat = 0x00030000 | (((uint32_t)address) << 8),
        .rxBuf = &rxData,
        .numOfBits = 24,
        .freq = 50000,
    };

    if (SoftSPIXfer(&readCmd) != 0)
    {
        return -1;
    }
    
    while (!readCmd.xferDone);      // Wait for transfer to complete.
    *data = rxData & 0x000000FF;

    return 0;
}

//==============================================================================

int KSZ8895WriteReg(uint8_t address, uint8_t data)
{
    SOFTSPI_TRANSFER xfer =
    {
        .dev = SOFTSPI_KSZ8895,
        .txDat = 0x00020000 | (((uint32_t)address) << 8) | data,
        .rxBuf = 0,
        .numOfBits = 24,
        .freq = 50000,
        .xferDone = 0
    };

    return SoftSPIXfer(&xfer);
}

//==============================================================================

void KSZ8895Reset( void )
{    
    LATDCLR = _LATD_LATD5_MASK; // Low
    DelayMs(100);               // Allow time for capacitive load to switch.
    LATDSET = _LATD_LATD5_MASK; // High
    DelayMs(300);               // Allow time for switch to power up.
}

// *****************************************************************************
// ************************** Static Functions *********************************
// *****************************************************************************