ZHCS363L August 2011 – March 2017 TRF7970A
PRODUCTION DATA.
The length of the modulation pulse is defined by the protocol selected in the ISO Control register 0x01. With a high Q antenna, the modulation pulse is typically prolonged, and the tag detects a longer pulse than intended. For such cases, the modulation pulse length can be corrected by using the TX Pulse Length Control register (0x06). If the register contains all zeros, then the pulse length is governed by the protocol selection. If the register contains a value other than 0x00, the pulse length is equal to the value of the register in 73.7-ns increments. This means the range of adjustment can be 73.7 ns to 18.8 µs.
Table 6-33 describes the TX Pulse Length Control register.
Function: Controls the length of TX pulse | |||
Default: 0x00 at POR = H or EN = L and at each write to ISO Control register. | |||
Bit | Name | Function | Description |
B7 | Pul_p2 | Pulse length MSB | The pulse range is 73.7 ns to 18.8 µs (1….255), step size 73.7 ns. All bits low (00): pulse length control is disabled. The following default timings are preset by the ISO Control register (0x01): 9.44 µs → ISO/IEC 15693 (TI Tag-It HF-I) 11 µs → Reserved 2.36 µs → ISO/IEC 14443 A at 106 kbps 1.4 µs → ISO/IEC 14443 A at 212 kbps 737 ns → ISO/IEC 14443 A at 424 kbps 442 ns → ISO/IEC 14443 A at 848 kbps; pulse length control disabled |
B6 | Pul_p1 | ||
B5 | Pul_p0 | ||
B4 | Pul_c4 | ||
B3 | Pul_c3 | ||
B2 | Pul_c2 | ||
B1 | Pul_c1 | ||
B0 | Pul_c0 | Pulse length LSB |