6.15.3.3.1 IRQ Status Register (0x0C)
Table 6-43 describes the IRQ Status register.
Table 6-43 IRQ Status Register (0x0C)
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 |
CRC error |
Indicates receive CRC error only if B7 (no RX CRC) of ISO Control register is set to 0. |
B3 |
Irq_err2 |
Parity error |
Indicates parity error for ISO/IEC 14443 A |
B2 |
Irq_err3 |
Byte framing or EOF error |
Indicates framing error |
B1 |
Irq_col |
Collision error |
Collision error for ISO/IEC 14443 A and ISO/IEC 15693 single subcarrier. Bit is set if more then 6 or 7 (as defined in register 0x10) are detected in 1 bit period of ISO/IEC 14443 A 106 kbps. Collision error bit can also be triggered by external noise. |
B0 |
Irq_noresp |
No response time interrupt |
No response within the "No-response time" defined in RX No Response Wait Time register (0x07). Signals the MCU that the next slot command can be sent. Only for ISO/IEC 15693. |
To reset (clear) the register 0x0C and the IRQ line, the register must be read. During Transmit the decoder is disabled, only bits B5 and B7 can be changed. During Receive only bit B6 can be changed, but does not trigger the IRQ line immediately. The IRQ signal is set at the end of Transmit and Receive phase.
Table 6-44 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. |