10 Peer-to-Peer Interoperability Results

This section covers the results of the interoperability between the existing TRF7970A peer-to-peer stack and the list of NFC-enabled devices mentioned earlier in the application report (see Table 1). Use the legend shown in Table 6 for the Target results in Table 7 and for the Initiator results in Table 8.

Based on the results of the interoperability tests, TI recommends using passive peer-to-peer modes as they have proven to be more consistent, reliable, and robust than active peer-to-peer modes.

Table 7 includes the interoperability results for test cases where the TRF7970A is a passive and active target. The results show that legacy NFC-enabled devices did not support sending a PSL REQ, instead they would poll for 106 kbps, 212 kbps, and 424 kbps separately. The newer devices go through the anticollision loop and immediately send a PSL_REQ up to 424 kbps for both active and passive communication at 106 kbps or 212 kbps up to 424 kbps. The smartphone devices are listed with model and release date to illustrate that the interoperability across all target modes is better for newer NFC-enabled devices. The TRF7970A peer-to-peer stack is replying to incoming commands SENS_REQ (polling at 106 kbps), and ATR_REQ (active polling at 106 kbps, or 212 kbps, or 424 kbps); however, no further commands are received from the initiator.

Table 8 includes the interoperability results for test cases where the TRF7970A is a passive and active initiator. The smartphone devices are listed with model and release date included to illustrate that the interoperability across all initiator modes is better for newer NFC-enabled devices. The TRF7970A peer-to-peer stack does not get a response from the devices that are failing for the SENS_REQ (polling at 106 kbps), and ATR_REQ (active polling at 106 kbps or 212 kbps). The peer-to-peer stack does not support incrementing from 106 kbps → 212 kbps or 424 kbps for both active and passive communication.

Table 9 shows the results for the time it took to send a 3.6kB file from the TRF7970A to the NFC-enabled devices listed. The NFC-enabled devices were the initiators (passive communication) at 424 kbps. The start edge was measured from the Transmit Complete Interrupt of the LLCP CONNECT PDU (sent from the TRF7970A to the NFC-enabled device). The end edge was measured at the RX Complete interrupt of the SNEP SUCCESS response. The results show that the throughput is highly related to the performance of the processor in the NFC-enabled device. The highest throughput was measured with the Nexus 10, which has the fastest processor.