Library Description

The library demonstrates the operation of the software single wire interface implementation.

Key functions:

• int8_t secureswi_init(T_SECURESWI_DIRSET inSet, T_SECURESWI_DIRSET outSet) - Initialize the SWI interface and pass the pin direction setting functions.
• void secureswi_sendBytes(uint8_t len,uint8_t *stBuf) - Encode data buffer and send the data to the SWI bus.
• void secureswi_receiveBytes(uint8_t len,uint8_t *stBuf) - Receive and decode data from the SWI bus.

Examples description

The application is composed of three sections :

• System Initialization - Initialize the GPIO sturcture and configure the serial port for logging data.
• Application Initialization - Initialize the driver and configure swi for communication.
• Application Task - Data is read from the secure chip. If the readout is successful the data is then printed on the serial port in the hex format.

void applicationTask()
{
     uint8_t bufferOut[128];

     cfg_atsha204a_swi_default.iface_type  = ATCA_SWI_IFACE;
     cfg_atsha204a_swi_default.devtype     = ATSHA204A;
     cfg_atsha204a_swi_default.atcaswi.bus = 1;
     cfg_atsha204a_swi_default.wake_delay  = 2560;
     cfg_atsha204a_swi_default.rx_retries  = 10;

     atcab_init(&cfg_atsha204a_swi_default);

     mikrobus_logWrite("Starting test",_LOG_LINE);

     memset(bufferOut,0,127);

     if (atcab_read_serial_number(bufferOut) == ATCA_SUCCESS)
     {
         mikrobus_logWrite("rn Serial number: ",_LOG_LINE);
         secureswi_printHex(bufferOut,9);
     }
     else
     {
         mikrobus_logWrite("rn Reading serial number failed...",_LOG_LINE);
         secureswi_printHex(bufferOut,sizeof(bufferOut));
     }

     Delay_ms (1500);
     memset (bufferOut, 0x00, 128);
     if (atcab_read_config_zone(bufferOut) == ATCA_SUCCESS)
     {
        mikrobus_logWrite("rnrn First 32 bytes of device configuration: ",_LOG_LINE);
        secureswi_printHex(bufferOut,32);
     }
     else
     {
        mikrobus_logWrite("rnrn Reading config zone failed...",_LOG_LINE);
        secureswi_printHex(bufferOut,sizeof(bufferOut));
     }

     while(1)
     {

     }
}

Other mikroE Libraries used in the example:

• Conversions
• C_String
• UART

Additional notes and informations

Depending on the development board you are using, you may need USB UART click, USB UART 2 click or RS232 click to connect to your PC, for development systems with no UART to USB interface available on the board. The terminal available in all MikroElektronika compilers, or any other terminal application of your choice, can be used to read the message.