User's Manual

TRF7970A
www.ti.com SLOS743K –AUGUST 2011–REVISED APRIL 2014
6.14.3.2.5 TX Pulse Length Control Register (0x06)
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. TX Pulse Length Control Register (0x06)
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.
B6 Pul_p1
All bits low (00): pulse length control is disabled.
B5 Pul_p0
The following default timings are preset by the ISO Control register (0x01):
B4 Pul_c4
9.44 µs → ISO15693 (TI Tag-It HF-I)
B3 Pul_c3
B2 Pul_c2 11 µs → Reserved
B1 Pul_c1
2.36 µs → ISO14443A at 106 kbps
1.4 µs → ISO14443A at 212 kbps
B0 Pul_c0 Pulse length LSB
737 ns → ISO14443A at 424 kbps
442 ns → ISO14443A at 848 kbps; pulse length control disabled
6.14.3.2.6 RX No Response Wait Time Register (0x07)
The RX No Response timer is controlled by the RX NO Response Wait Time Register 0x07. This timer
measures the time from the start of slot in the anticollision sequence until the start of tag response. If there
is no tag response in the defined time, an interrupt request is sent and a flag is set in IRQ status control
register 0x0C. This enables the external controller to be relieved of the task of detecting empty slots. The
wait time is stored in the register in increments of 37.76 µ s. This register is also preset, automatically, for
every new protocol selection. Sending a Reset FIFO (0x0F) direct command after a TX Complete interrupt
will disable this feature.
Table 6-34. RX No Response Wait Time Register (0x07)
Function: Defines the time when "no response" interrupt is sent; only for ISO15693
Default: 0x0E at POR = H or EN = L and at each write to ISO Control register
Bit Name Function Description
B7 NoResp7 No response MSB
Defines the time when "no response" interrupt is sent. It starts from the end of
B6 NoResp6
TX EOF. RX no response wait range is 37.76 µs to 9628 µs (1 to 255), step
size is: 37.76 µs.
B5 NoResp5
The following default timings are preset by the ISO Control register (0x01):
B4 NoResp4
B3 NoResp3
390 µs → Reserved
B2 NoResp2
529 µs → for all protocols supported, but not listed here
B1 NoResp1
604 µs → Reserved
755 µs → ISO15693 high data rate (TI Tag-It HF-I)
B0 NoResp0 No response LSB
1812 µs → ISO15693 low data rate (TI Tag-It HF-I)
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