NXP Semiconductors
FXTH87E
FXTH87E, Family of Tire Pressure Monitor Sensors
Bit
W
7
6
5
4
RFIAK
0
3
2
1
0
RFMRST
0
Reset
0
0
0
0
0
0
= Reserved
Table 149.ꢀRFCR7 field descriptions
Field
Description
RF Interrupt Flag— The read-only RFIF status bit indicates if the RF transmission has ended properly when
using the data buffer mode and the SEND bit has been cleared. Writes to this bit will be ignored. The RFIF
status bit is cleared by writing a logical one to the RFIAK bit or the RFMRST bit. RFMRST signal clears this
bit.
7
RFIF
0ꢀRF transmission in progress or not in the data buffer mode.
1ꢀRF transmission completed in the data buffer mode.
RF Transmission Error Flag— The read-only RFEF status bit indicates if there was an error in the current or
prior RF transmission as described in Section 15.6.4 "Transmission error". Writes to this bit will be ignored.
The RFEF status bit is cleared by writing a logical one to the RFIAK bit or the RFMRST bit. RFMRST signal
clears this bit.
6
RFEF
0ꢀNo RF transmission error occurred.
1ꢀRF transmission error occurred.
RF LVD Trigger Flag— When the RF LVD is enabled and the supply voltage falls below the threshold, the
read-only RFVF flag will be set if the RFLVDEN bit is set. Writes to this bit will be ignored. The RFVF status
bit is cleared by writing a logical one to the RFIAK bit or the RFMRST bit. RFMRST signal clears this bit
5
RFVF
0ꢀVoltage is and has been above RF LVD rising threshold or the RF LVD is disabled.
1ꢀVoltage has dropped below the RF LVD falling threshold since last reset of this bit.
Acknowledge RF Interrupt Flags— Writing a one to the RFIAK bit clears the RFIF, RFEF and RFVF flag
bits. Writing a zero to the RFIAK bit has no effect on the RFIF, RFEF and RFVF flag bits. The RFMRST
signal has no effect on this bit.
4
RFIAK
0ꢀNo effect.
1ꢀClear the RFIF, RFEF, and RFVF bits.
RF Interrupt Enable— The RFIEN bit enables the RFIF, the RFEF and the RFVF bits to generate an
interrupt to the MCU. The RFMRST signal clears this bit.
3
0ꢀRF interrupts disabled.
1ꢀRF interrupts enabled.
RFIEN
RF LVD Enable — When the RFLVDEN bit is set, the RF LVD circuit will be enabled, and the RF LVD
events are routed to the RF LVD Trigger Flag. This bit is cleared by the RFMRST signal.
2
0ꢀRF LVD disabled.
1ꢀRF LVD enabled.
RFLVDEN
RF Clear To Send Status— When the RCTS bit is set the RF XCO, VCO and PLL have started and locked
and the RFM is ready to send data. This bit is cleared by the RFMRST signal.
1
0ꢀRFM not ready to send.
1ꢀRFM ready to send.
RCTS
RFM Reset — Writing a one to the RFMRST bit will completely reset the RFM and its registers. This bit is
not affected by a reset of the MCU. This bit will always read as a zero.
0
0ꢀNo effect.
RFMRST
1ꢀReset RFM.
FXTH87ERM
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Reference manual
Rev. 5.0 — 4 February 2019
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