It might be required in some cases (when using an external Entry Point for example) to call Agnos only after SELECT PPSE and FINAL SELECT have been performed. Agnos is capable of handling such a scenario. Below the steps to perform (once the application selection was made).

Transaction Execution

 The following Steps shall be executed for each Transaction.

Step 1

Each transaction must begin with a call to ola_contactless_flush_aid_supported().

Step 2

Transaction Related Data (TRD) must be passed to OLA using ola_emv_set_tag() for each TRD data elements (i.e., Transaction Type '9C', Transaction Date '9A', Transaction Time '9F21', Authorized Amount '9F02', Other Amount '9F03',...).

...

ola_emv_set_tag(0x9C, “\x00”, 1);
ola_emv_set_tag(0x9A, “\x23\x05\x18”, 3);
… 

Step 3

Pass the FCI returned by the FINAL SELECT ‘6F’ using ola_emv_set_tag()

...

uint8_t fci[] = {
        0x6F,0x3F,0x84,0x08,0xA0,0x00,0x00,0x00,0x25,0x01,
        0x04,0x03,0xA5,0x33,0x50,0x10,0x50,0x65,0x72,0x73,
        0x6F,0x6E,0x61,0x6C,0x20,0x41,0x63,0x63,0x6F,0x75,
        0x6E,0x74,0x5F,0x2D,0x04,0x45,0x4E,0x46,0x52,0x9F,
        0x38,0x14,0x9F,0x6E,0x04,0x9F,0x35,0x01,0x9F,0x37,
        0x04,0x95,0x05,0x9F,0x34,0x03,0x9F,0x02,0x06,0x9F,
        0x03,0x06,0x87,0x01,0x01
};

ola_emv_set_tag(0x6F, fci, sizeof(fci));

Step 4

Pass the Kernel ID of the Kernel to activate with Tag ‘9F2A’ using ola_emv_set_tag().

...

ola_emv_set_tag(0x9F2A, 0x04, 1); 

Step 5

Set Configuration Data of Selected Candidate (Reader Combination) for the transaction using ola_contactless_add_aid_supported().

...

ola_contactless_add_aid_supported(aid, sizeof(aid), partial_selection_indicator, kernel_id, cfg_data, sizeof(cfg_data));

Step 6

Execution the Transaction using ola_contacless_do_transaction().

Step 7

Get Outcome Parameters, UI Request Messages and retrieval of Authorization Data Elements

...

uint8_t un[4];
uint8_t pan[10];
uint16_t len;

ola_emv_get_tag(0x9F37, un, &len);
ola_emv_get_tag(0x5A, pan, &len);
…

Step 8

It is important calling the function ola_contacless_clean() once the Transaction is completed.