[ECOS] SPI send data

[jayant biswas <biswasj@gmail.com>]

Hi Ilija,

Thank you for your response to the previous question, I am using SPI1
and have changed the config accordingly and have noticed with a
voltmeter that the pin PA8 does stay high and goes low when the SPI is
active. I have another question now about sending data. If you take a
look at the timing diagrams on page 10 of the datasheet
(http://www.analog.com/static/imported-files/data_sheets/AD8400_8402_8403.pdf)
for the programmable potentiometer that I am using and then my code
below, could you maybe hint at what I am doing wrong?

Regards,
Jayant

So this code based on the loopback test that comes with the spi package in ecos.

#include <cyg/infra/cyg_type.h>
#include <cyg/infra/testcase.h>         // Test macros
#include <cyg/infra/cyg_ass.h>          // Assertion macros
#include <cyg/infra/diag.h>             // Diagnostic output

#include <cyg/hal/hal_arch.h>           // CYGNUM_HAL_STACK_SIZE_TYPICAL
#include <cyg/kernel/kapi.h>

#include <cyg/io/spi.h>                 // Common SPI API
#include <cyg/io/spi_stm32.h>           // STM32 data structures

#include <string.h>

//---------------------------------------------------------------------------
// Thread data structures.

cyg_uint8 stack [CYGNUM_HAL_STACK_SIZE_TYPICAL];
cyg_thread thread_data;
cyg_handle_t thread_handle;

externC cyg_spi_cortexm_stm32_bus_t cyg_spi_stm32_bus2;

//---------------------------------------------------------------------------
// SPI loopback device driver data structures.

cyg_spi_cortexm_stm32_device_t loopback_device = {
    .spi_device.spi_bus = &cyg_spi_stm32_bus1.spi_bus,
    .dev_num = 0 ,                      // Only 1 device.
    .cl_pol = 1,
    .cl_pha = 1,
    .cl_brate = 8000000,                // Nominal 8Mhz.
    .cs_up_udly = 1,
    .cs_dw_udly = 1,
    .tr_bt_udly = 1,
    .bus_16bit = true, // *** MODIFIED this because my data is 10 bits
};

//---------------------------------------------------------------------------

//const char tx_data[] = {0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1}; // To set
maximum resistance at address 00
const char tx_data[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; // To set
minimim resistance at address 00
const char tx_data1[] = "Testing extended API...";
const char tx_data2[] = "Testing extended API for a second transaction.";

char rx_data [sizeof(tx_data)];
char rx_data1 [sizeof(tx_data1)];
char rx_data2 [sizeof(tx_data2)];

//---------------------------------------------------------------------------
// Run single loopback transaction using simple transfer API call.

void run_test_1 (cyg_bool polled)
{
    diag_printf ("Test 1 : Simple transfer test (polled = %d).\n",
polled ? 1 : 0);
    cyg_spi_transfer (&loopback_device.spi_device, polled, sizeof (tx_data),
        (const cyg_uint8*) &tx_data[0], (cyg_uint8*) &rx_data[0]);

    diag_printf ("    Tx data : %s\n", tx_data);
    diag_printf ("    Rx data : %s\n", rx_data);
    CYG_ASSERT (memcmp (tx_data, rx_data, sizeof (tx_data)) == 0,
        "Simple transfer loopback failed - mismatched data.\n");
}


//---------------------------------------------------------------------------
// Run all PL022 SPI interface loopback tests.

void run_tests (void)
{
    diag_printf ("Running STM32 SPI driver loopback tests.\n");
    run_test_1 (true);
    CYG_TEST_PASS_FINISH ("Loopback tests ran OK");
}

//---------------------------------------------------------------------------
// User startup - tests are run in their own thread.

void cyg_user_start(void)
{
    CYG_TEST_INIT();
    cyg_thread_create(
        10,                                   // Arbitrary priority
        (cyg_thread_entry_t*) run_tests,      // Thread entry point
        0,                                    //
        "test_thread",                        // Thread name
        &stack[0],                            // Stack
        CYGNUM_HAL_STACK_SIZE_TYPICAL,        // Stack size
        &thread_handle,                       // Thread handle
        &thread_data                          // Thread data structure
    );
    cyg_thread_resume(thread_handle);
    cyg_scheduler_start();
}

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

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