Other Parts Discussed in Thread: TIDA-00217, RF430CL330H, TRF7970A
Hello,
I was through the Firmware designed to Interface DLP-7970ABP and MSP430G2 Launch pad. I came across these lines to communicate with ISO14443B tags in nfc_appISO14443B()
TRF79xxA_setupInitiator(0x0C); // Configure the TRF79xxA for ISO14443B @ 106kbps
// When a PICC is exposed to an un-modulated operating field
// it shall be able to accept a quest within 5 ms.
// PCDs should periodically present an un-modulated field of at least
// 5.1 mSec duration. (ISO14443-3)
// *NOTE* Guard time extended to 10 milliseconds in order to support passively
// powered RF430CL330H designs such as seen in TIDA-00217.
MCU_delayMillisecond(10);
if (ISO14443B_sendPollCmd(REQB,0)) // Issue REQB Command with 1 slot to start
{
bTagFound = true;
}
I believe that the TRF79xxA_setupInitiator(0x0C) turns on the RF field with 10%ASK. Aren't we exposing the PICC to the modulated Signal (10%ASK and 13.56Mhz) for 10ms? Where is the field beoming unmodulated again? Are we doing a soft reset before the MCU_delay()?