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SLOS743L – AUGUST 2011 – REVISED MARCH 2017
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Detailed Description
Copyright © 2011–2017, Texas Instruments Incorporated
describes the IRQ Status register when used for NFC and card emulation operation.
Table 6-44. IRQ Status Register (0x0C) for NFC and Card Emulation Operation
Function:
Information available about TRF7970A IRQ and TX/RX status
Default:
0x00 at POR = H or EN = L, and at each write to the ISO Control Register 0x01. It is also automatically reset at the end of a read
phase. The reset also removes the IRQ flag.
Bit
Name
Function
Description
B7
Irq_tx
IRQ set due to end of TX
Signals that TX is in progress. The flag is set at the start of TX but the interrupt
request (IRQ = 1) is sent when TX is finished.
B6
Irg_srx
IRQ set due to RX start
Signals that RX SOF was received and RX is in progress. The flag is set at the
start of RX but the interrupt request (IRQ = 1) is sent when RX is finished.
B5
Irq_fifo
Signals the FIFO level
Signals FIFO high or low as set in the Adjustable FIFO IRQ Levels (0x14)
register
B4
Irq_err1
Protocol error
Any protocol error
B3
Irq_sdd
SDD completed
SDD (passive target at 106 kbps) successfully finished
B2
Irq_rf
RF field change
Sufficient RF signal level for operation was reached or lost
B1
Irq_col
RF collision avoidance
finished
The system has finished collision avoidance and the minimum wait time is
elapsed.
B0
Irq_col_err
RF collision avoidance not
finished successfully
The external RF field was present so the collision avoidance could not be
carried out.
6.15.3.3.2 Interrupt Mask Register (0x0D) and Collision Position Register (0x0E)
describes the Interrupt Mask register.
describes the Collision Position register.
Table 6-45. Interrupt Mask Register (0x0D)
Default:
0x3E at POR = H and EN = L. Collision bits reset automatically after read operation.
Bit
Name
Function
Description
B7
Col9
Bit position of collision MSB
Supports ISO/IEC 14443 A
B6
Col8
Bit position of collision
B5
En_irq_fifo
Interrupt enable for FIFO
Default = 1
B4
En_irq_err1
Interrupt enable for CRC
Default = 1
B3
En_irq_err2
Interrupt enable for Parity
Default = 1
B2
En_irq_err3
Interrupt enable for Framing
error or EOF
Default = 1
B1
En_irq_col
Interrupt enable for collision
error
Default = 1
B0
En_irq_noresp
Enables no-response
interrupt
Default = 0
Table 6-46. Collision Position Register (0x0E)
Function:
Displays the bit position of collision or error
Default:
0x00 at POR = H and EN = L. Automatically reset after read operation.
Bit
Name
Function
Description
B7
Col7
Bit position of collision MSB
ISO/IEC 14443 A mainly supported, in the other protocols this register shows
the bit position of error. Frame, SOF, EOF, parity, or CRC error.
B6
Col6
B5
Col5
B4
Col4
B3
Col3
B2
Col2
B1
Col1
B0
Col0
Bit position of collision LSB