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Problem with NFC-ST25R95 tag detection

Ashish_
Associate II

Hello,

I'm use ST25R95. I'm facing problem with Tag detection in WEF mode.

Its working fine with WEF from Time out and IRQ_In low pulse, But not get wake from sleep mode

when I configured it for a Tag detection.

Observation: I seen during Tag Calibration that there is no change appear in result of calibration Idle command with

Tag or Without Tag, all time the pattern of response even without Tag or with Tag calibration is same. Obvious that

calibration should be without Tag, but I tried with tag to check what changes happen in response from slave, but there is no change, I get always same response pattern.

I'm use these commands for calibration and to put in WEF mode respectively, 

{ST25R95_COMMAND_IDLE, 0x0E, 0x03, 0xA1, 0x00, 0xF8, 0x01, 0x18, 0x00, 0x00, 0x60, 0x60, 0x00, 0x00, 0x3F, 0x01};

{ST25R95_COMMAND_IDLE, 0x0E, 0x0A, 0x21, 0x00, 0x79, 0x01, 0x18, 0x00, 0x00, 0x60, 0x60, 0x74, 0x84, 0x3F, 0x08};

Also with value of gRFAL.wum.cfg.indAmp.delta = 4U, Its woke up without Tag and response is 02(Tag detection),

when I change this value from 4U to 8U, I don't get wake up event. 

 

Kindly help me out.

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10 REPLIES 10

Hello,

the ST25R95 antenna matching circuit shall be calculated based on the antenna impedance measured on the input of antenna cable. A good impedance matching in free air is necessary to maximize the tg detection mechanism. 5R/3uH impedance is measured at cable input or antenna without cable? 

best regards,

Henry Crane