Writing to an external SD card in BLE stack w/ CC2540

Thank you for your reply, Oleg

I think I understand what you are saying. Basically I can use a single new profile with the included 8051 header files to read in my data through an ADC and other inputs and to isolate the relevant input data. In that same profile, I can take the data and put them into strings that come from sampling the sensors, then send this using the header files I have found for writing to an external SD card through the SPI interface. This file would then be sent as a .txt file (though admittedly I'm not sure how to actually set this to be a type of file, so maybe it will just be understood by the iOS app without any file extension) "

The co-existence problem hopefully will not be an issue, because it will basically be recording data until something triggers it to stop, then when it stops it would close that .txt file and send it to the phone. That's how I see it working anyway. 

Thank you very much for your help on this. 

Crippling the radio is definitely a problem, or better said, having reads/writes to SDCard in the same CPU cycles/memory pool than the BLE stack is pretty much impossible to the best of my experience.

I have accomplished reads/writes to SDCard in CC2540, and separately had application code to relay serial port data to a BLE enabled iPhone, but when attempting both at the same time, the radio (BLE) always breaks at some point in execution.

As of now, our project has used Chan's FatFS and PetitFS with SD-SPI through bit-banging (_hal_uart_spi.h/.c doesn't really work on cc2540, even on the supposedly working ALT2 configuration so bit-banging had to be implemented). Both to no success as BLE breaks at about 20-30 ticks (20-30 seconds, 1 open/write/close per second).

Needless to say this is surely a memory issue. PetitFS supposedly restricts heap usage to under 100B since it writes only from sector start and only writes whole sectors, but in real scenarios where you want to efficiently append to a sector of data with PetitFS, you have to keep a 512B buffer in application memory which pretty much emulates the standard, non-petit FatFS, so it's back to square one on memory usage.

Just to give a better overview of the issues arising on these kinds of implementations, we are considering adding another CC2540 to our design, and placing 2 of them in series dividing the workload of SDCard operations and BLE operation between them so as not to break BLE. It's overkill, but after 3 months of testing it's the only real solution we can think of.

Hello,

Could anyone give us some guidelines about how one can read/write a file on a sd card through cc2540 ? I am working with FATFS by Chan and the SimpleBLEPeripheral example. Could anyone help me? Unfortunately my code doesn't work.

thank you in advance,

Hello,

Thank you very very much for your message. The first problems is with Chan's FATFS, specifically with diskio.c. It gives as warnings the "MMC_disk_initialize", "ATA_disk_read", "MMC_disk_read" and "USB_disk_read". 

My target is to send a file "message.txt" to the SD card. I am based on the SimpleBLEPeripheral Example and the spi_master_send.c example with a rate for the SPI = 115200 .

The SD card is 2GB. And my code is the following:

/* Initialize SPI interface and external memory */
void memInit(void)
{
    //*** Setup USART 0 SPI at alternate location 1 *** //
    // Configure USART0 for Alternative 1 => Port P0 (PERCFG.U0CFG = 0).
    PERCFG = (PERCFG & ~PERCFG_U0CFG) | PERCFG_U0CFG_ALT1;    
    // Give priority to USART 0 over Timer 1 for port 0 pins.
    P2DIR &= P2DIR_PRIP0_USART0;
   // Set pins 2, 3 and 5 as peripheral I/O and pin 4 as GPIO output.
    P0SEL = (P0SEL & ~BIT4) | BIT5 | BIT3 | BIT2;
    P0DIR |= BIT4;
    // Configure CS (P1_7/P1_2) as output

    // Configure P1_0 as GPIO output for LED1.
    P1SEL &= BIT0;      // GPIO.
    P1DIR |= BIT0;      // Output.
    P1_0 = 0;           // LED1 off.
    
    CS = CS_DISABLED;

//*** Configuration - Setup the SPI interface ***
    // Fill array with bytes to send.
    uint8 value = 0x00;
    int i;
    for (i = 0; i < BUFFER_SIZE; i++)
    {
        txBufferMaster[i] = value++;
    }
    
    // Set USART to SPI mode and Master mode.
    U0CSR &= ~(U0CSR_MODE | U0CSR_SLAVE);
    
        
     // Set:
    // - mantissa value
    // - exponent value
    // - clock phase to be centered on first edge of SCK period
    // - negative clock polarity (SCK low when idle)
    // - bit order for transfers to LSB first
    U0BAUD = SPI_BAUD_M;
    U0GCR = (U0GCR & ~(U0GCR_BAUD_E | U0GCR_CPOL | U0GCR_CPHA | U0GCR_ORDER))
        | SPI_BAUD_E;
    
/* Transfer data */
    // Clear SSN, the SPI slave is active when SSN is low.
     CS = CS_DISABLED;
    
     for (i = 0; i < BUFFER_SIZE; i++)
    {
        // Write byte to USART0 buffer (transmit data).
        U0DBUF = txBufferMaster[i];

        // Check if byte is transmitted.
        while(!(U0CSR & U0CSR_TX_BYTE));

        // Clear transmit byte status.
        U0CSR &= ~U0CSR_TX_BYTE;
    }
    
    CS = CS_ENABLED;
 
    FATFS FatFs;   /* Work area (file system object) for logical drive */
    /* Register work area to the default drive */
    if(f_mount(&FatFs, "", 1)==FR_OK) {
      FIL fil;       /* File object */
      UINT bw;
      CS = CS_ENABLED;
      WAIT_1_3US(2);
     
    /* Open a text file */
      f_open(&fil, "message.txt", FA_OPEN_ALWAYS | FA_READ | FA_WRITE | FA_CREATE_ALWAYS);
      WAIT_1_3US(80);

    /* Read all lines and display it */
      f_write(&fil, "Hello world!\r\n", 14, &bw);
      WAIT_1_3US(80);
    
    /* Close the file */
      f_close(&fil);
      CS = CS_DISABLED;   
    }
 
    while(1);

}

Which is the problem ? It is the first time I am programming the cc2540 and I don't understand.

Thank you in advance,

Hello,

Firstly, thank you very much for your message and help. I am using the IAR Embedded Workbench. The thread you sent me says that "Unfortunately, the page you've requested no longer exists. Please use the search form above to locate the information you're interested in."

I have started from the scratch with cc2540. To notice that now I don't have any error or warning! I resolve these! I finally use only the diskio.h, the ff.h and the integer.h. Nothing else.

Any advice about my code. Is something wrong? As I told I have based on the spi_master_send.c from the peripheral exampes of cc2540 and the SimpleBLEPeripheral project. The reason that the file is not created is possibly the baud rate or the definition of the clock? Should I possibly create another file for the sd card, based on the spi_slave_receive.c?  

Could you please tell me which file of Chan's Library you use in order to recognize the existence of the SD card ?

Thank you again,

Thank you for the link! I have already read it. However, it doesn't help me. I will try to contact with Tiago Borba.

My project need to use sd card to save files. And then , I would like to send the file to the central BLE (the mobile phone).
Can the cc2540 support this function?
So, I use the FATFs of Chan's library and I try to create a file "message.txt" in the SD card through SPI.

Thank you again,

Dear Oleg Komlev,

My answer is above! I don't understand why it is above! In addition to my previous message, when I will transfer files to the memory, I will disable the BLE radio.

Thank you again for your help!

Kind Regards,

Hello,

Thank you very much for your help and your time. I am sorry for disturbing you again.

For the SPI I use the examples, I have already mentioned in order to be more sure that this will work. Now I use the generic example of

http://elm-chan.org/fsw/ff/ff12.zip

and I cannot initialize SDCard  (diskio.c, sdcard,.h).

Also, some here at the forum mention that the best speed of SPI is 400KHz. Has anyone achieved this experiment in order to give us some guidelines ?

Thank you very much.

Thank you very much!

Do you know where I should call my function that initializes SPI and SD card?

I call it in the  osalInitTasks() and it gives me a linking error! I don't understand why!

void osalInitTasks()

{

  ... ... ...

memorySPIinit();

  ... ... ...

}

It gives "Linking Error[e27]: Entry "SD_Command::?relay" in module OSAL_SimpleBLEPeripheral ( C:\Texas  ..... ..... .... "

Have a nice day,

Hello,

I have built the code without errors and when I am trying to call the SD_SPI_initialization() function I get the error :

What am I missing? I don't understand! I call my function from the "performPeriodicTask()" function of SimpleBLEPeripheral.c .

Could anyone help me ? I am using cc2540 with 128K flash and INT_HEAP_LEN=3072.

Thank you,