AN2319

Application examples

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3

Application examples

Acquiring the UID is quite easy when using high-level SRIxx tags, but additional actions are

required when using low-level SR176 memories.

After sending the INITIATE() and SELECT() command sequence to the tag(s), send a

GET_UID()

command to identify UID values.

SRIxx tags directly return the UID after receiving the GET_UID() command, while SR176

tags do not reply to this command.

If a tag is detected in the reader RF field but no reply is returned after a GET_UID()

command, it is probably a SR176 tag. In this case, the reader must read a specific memory

address to retrieve its UID as shown in Example 2.

The example shown in Section 3.2 is the body of the CRX14_Get_UID() function used in

Example 1.

3.1

Example 1: high-level mnemonic source code

This is an example of a UID acquisition loop using a high-level mnemonic source code.

UCHAR UID[8];

UCHAR blockSize, NoOfBlock, WriteblockAddress;

/********************************************

****

Manage all SRxx

********************************************/

CRX14_Set_Param(0x00);

//RF Off (accessing the Parameter Register of CRX14)

CRX14_Set_Param(0x10);

//RF On

if (CRX14_Initiate())

// (INITIATE() command)

{

CRX14_Select(Chip_ID); (SELECT() command)

CRX14_Get_UID(UID);

if((UID[7]==0xd0)&&(UID[6]==0x02))

switch (((UID[5] & 0xFC)>>2))

{

case 2: //SR176

blockSize=2; NoOfBlock=16; WriteblockAddress=4;

break;

case 3: //SRIX4K

blockSize=4; NoOfBlock=128; WriteblockAddress=7;

break;

}

}