ISO/IEC 14443B
The activation of higher bit rates according to the ISO/IEC 14443B. In the Protocol Info in the ATQB the PICC returns the Bit_Rate_Capability. The bit rate then is selected in the Param 2 of the ATRIB command. The following command then is the first command using the selected higher bit rates. For the Micore settings for the communication according to the ISO/IEC 14443B standard bit rate (106 kbit/s) .

Table 7: ISO/IEC14443B HBR Register Settings PCD to PICCMicore register settings for sending ISO/IEC14443B HBR6
Register Name Address 106 212 424 848
RegCoderControl 0×14 0×20 0×18 0×10 0×08
           

 

Table 8: ISO/IEC14443B HBR Register Settings PICC to PCDMicore register settings for receiving ISO/IEC14443B HBR
Register Name Address 106 212 424 848
RegRxControl1 0×19 0×73 0×53 0×33 0×13
RegRxThreshold 0x1C 0×88 0×50 0×50 0×50

Remark: The MF RC531 and the CL RC632 were specified and qualified before the ISO/IEC 14443 came up with HBR. The datasheet does not mention it at all. But tests have shown, the MF RC531 and CL RC632 do support the ISO/IEC14443 B higher bit rates.
The use of this Philips IC according to ISO14.443 Type B might infringe third party patent rights. A purchaser of this Philips IC has to take care for appropriate third party patent licenses.

PCD Antenna design constraints
There are no specific antenna design constraints for HBR, if the PCD antenna design was done properly according to [4] and [5]. However, it is recommended to check the pulse shapes and the overall performance with HBR against the ISO/IEC 14443 requirements (see chapter 4.1). It is a physical fact, that higher data rates in general require a higher bandwidth and a higher signal to noise ratio in an RF system, so in some cases it might be more efficient to reduce the quality factor of the PCD antenna to achieve a better communication stability in the field. A lower quality factor also makes the antenna more stable against detuning, which could be caused by environmental changes as well as manufacturing tolerances, and does not necessarily decrease the operating distance. A target quality factor of approximately 21 turns out to be an appropriate value to start with, if not otherwise defined.

Tx Pulse shapes for HBR
Basic requirements
The pulse shape requirements for HBR are shown in Fig 1 and Table 10:. According to the ISO/IEC 14443, overshoots shall remain within ± 0,1 x (1-a) of HINITIAL. The parameter a in Fig 1 shall in the range as specified in Table 9: for HBR.

Table 9: Parameter a
Parameter 212 kbit/s 424 kbit/s 848 kbit/s
  min max min max min max
a 0 0,2 0 0,35 0 0,6

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Fig 1. Pulse shape for HBR

Table 10: Timings of the HBR pulses
Times 212 kbit/s 424 kbit/s 848 kbit/s
  min max min max min max
t1 15/fc 20/fc 8/fc 10/fc 4/fc 5/fc
t2 8/fc t1 4/fc t1 2/fc t1
t3 0 12/fc 0 10/fc 0 8/fc

Measurement example
The following example shows the carrier signal of a PCD, which covers HBR (see Fig 2). The bit rate was switched to 424 kbit/ s and one transmit pulse was measured with an oscilloscope using a Reference-PICC and the Mfout pin of the Micore chip to trigger on the modulation pulse. The spikes at t = 0 and t = 0.6μs, which are related to the trigger signal, shall be ignored in the measurement, because the Mfout pin is not used in the real application, but just for the measurement.
Remark: To get an accurate result, one complete pulse was captured, and the negative half of the signal was multiplied with –1. Thus the signal seems to show a 27 MHz carrier, even though the carrier of course has a frequency of fc = 13.56MHz.

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Fig 2. Typical pulse shape example for 424 kbit/s

In this example the modulation index can be read as approximately 70%, which is equivalent to a ≈ 17%, which gives the points to measure the times t1, t2, and t3:
0.9 + 0.1⋅ a = 0.917
(1+ a)2 = 0.585
With these values the required times can be calculated and crosschecked with the measurement (read from Fig 2), as shown in Table 11:.

Table 11: Timing example of the HBR pulses
Times 424 kbit/s requirement 424 kbit/s measurement
  min max measured
t1 0.590 µs 0.737µs 0.66 µs
t2 0.295 µs 0.66 µs 0.46 µs
t3 0 0.885 µs 0.45 µs