SPI from HPS through FPGA not working

Hi ask

I have the same issue as you described in this thread. How did you manage to get it to work?

I'm not using Linux but uCos, but I still can't make the SPI controller start transmitting data. It just puts the data into the FIFO buffer.

I have verified that my pin mapping is correct:

- CS pin can be toggled (Can be set low by SPI controller or by PIO CS pin, both works)

- SS pin can be toggled (selecting SPI mode 0 or 3).

I can break in my code and using the debugger I can select another SPI frameformat (TI instead of Motorola).

After this "trick" I can write data into the DR register and data gets transmitted (until SPI driver is disabled/enabled again).

Here is my init function:

ALT_STATUS_CODE FramDriver_Init(ALT_SPI_CTLR_t eAltSPIModNum){
    static uint8_t u8RunOnce = 1;
    ALT_STATUS_CODE eAltStatusCode = ALT_E_SUCCESS;
    ALT_SPI_CONFIG_t cfg =
    {
        .frame_size    = ALT_SPI_DFS_8BIT,
        .frame_format  = ALT_SPI_FRF_SPI, 
        .clk_phase     = ALT_SPI_SCPH_TOGGLE_START, 
        .clk_polarity  = ALT_SPI_SCPOL_INACTIVE_HIGH, 
        .transfer_mode = ALT_SPI_TMOD_TXRX,
        .loopback_mode = false,
	.slave_output_enable = true
    };
    // Make sure CS pin is high before initializing SPI peripheral. Is also pulled up externally...
    SET_CS_PIN_HIGH;
    if (1 == u8RunOnce)
    {
    	u8RunOnce = 0;
    	eAltStatusCode = alt_spi_init(eAltSPIModNum, &stAltSPIdevice);
    }
    eAltStatusCode = alt_spi_disable(&stAltSPIdevice);
    if (eAltStatusCode == ALT_E_SUCCESS)
    {
    	eAltStatusCode = alt_spi_config_set(&stAltSPIdevice, &cfg);
    }
    if (eAltStatusCode == ALT_E_SUCCESS)
    {
        eAltStatusCode = alt_spi_speed_set(&stAltSPIdevice, SPI_SPEED);
    }
    if (eAltStatusCode == ALT_E_SUCCESS)
    {
    	eAltStatusCode = alt_spi_slave_select_enable(&stAltSPIdevice, SPI_SLAVE_DEVICE);
    }
    if (eAltStatusCode == ALT_E_SUCCESS)
    {
        eAltStatusCode = alt_spi_enable(&stAltSPIdevice);
    }
    return eAltStatusCode;
}

Here is my write function:

ALT_STATUS_CODE FramDriverReadStatusRegister(uint8_t *uip8Status){
    ALT_STATUS_CODE eAltStatusCode = ALT_E_SUCCESS;
    const uint16_t au16TxOpCodeBuffer = {(uint16_t)OP_CODE_RDSR, 0x0000};
    uint16_t au16RxBuffer = {0x0000, 0x0000};
    // Check if SPI is initialized!
    if (0 == stAltSPIdevice.location)
    {
        // SPI is not initialized -> Return BAD_OPERATION
        return ALT_E_BAD_OPERATION;
    }
    // Handle CS pin manually!!!
    SET_CS_PIN_LOW;
    // Debug
    alt_spi_int_clear(&stAltSPIdevice, ALT_SPI_STATUS_TXEI);
    alt_spi_int_clear(&stAltSPIdevice, ALT_SPI_STATUS_RXUI);
    alt_spi_int_clear(&stAltSPIdevice, ALT_SPI_STATUS_ALL);
    // Write Op Code for Read Status register (OP_CODE_RDSR)
    eAltStatusCode = alt_spi_tx_fifo_enq(&stAltSPIdevice, au16TxOpCodeBuffer);
    // Wait for FIFO to be empty
    while(ALT_E_TRUE != alt_spi_tx_fifo_is_empty(&stAltSPIdevice));
    // Wait for transfer to complete! -> Poll busy flag!
    while (ALT_E_TRUE == alt_spi_is_busy(&stAltSPIdevice));
    // Read back Status Register from device (Size is specified to 1 byte)
    eAltStatusCode = alt_spi_rx_fifo_deq(&stAltSPIdevice, au16RxBuffer);
    // Return status register in uip8Status
    *uip8Status = (uint8_t) (au16RxBuffer & 0x00FF);
    // Handle CS pin manually!!!
    SET_CS_PIN_HIGH;
    return eAltStatusCode;
}

I have read all manuals for HPS and Cyclone V regarding SPI and TX should start if the following conditions are met:

--- Quote Start ---

The SPI master starts data transfers when all the following conditions are met:

• The SPI master is enabled

• There is at least one valid entry in the transmit FIFO buffer

• A slave device is selected

--- Quote End ---

I can see all three conditions in my SPI status registers, but still no output.

Any help would be appreciated!

Best regards

Brian

P.S.

I tried the command sequence above from u-boot, but I can't make it write out data...