NXP Semiconductors
FXTH87E
FXTH87E, Family of Tire Pressure Monitor Sensors
Table 136.ꢀRFM control register 1 (RFCR1) (address $0031)
Bit
R
7
6
5
4
3
2
1
0
FRM[7:0]
W
Reset
0
0
0
0
0
0
0
0
Table 137.ꢀRFCR1 field descriptions
Field
Description
Frame Bit Length — The FRM[7:0] control bits select the number of bits in each datagram. The number of
bits is determined by the binary value of the FRM[7:0] bits plus one. This makes the range of bits from 2 to
256. A value of $00 for the FRM[7:0] control bits will result in no frames being sent. The FRM[7:0] control
bits are cleared by RFMRST signal.
7-0
FRM[7:0]
15.11 RFM control register 2 — RFCR2
The RFCR2 register contains eight control bits for the RFM as described in Table 138.
Table 138.ꢀRFM control register 2 (RFCR2) (address $0032)
Bit
R
7
SEND
0
6
RPAGE
0
5
EOM
0
4
3
2
PWR[4:0]
0
1
0
W
Reset
0
0
0
0
Table 139.ꢀRFCR2 field descriptions
Field
Description
Transmission Start Control — The SEND control bit starts the transmission of data held in the RFM data
buffer according to the bit length specified by the FRM[7:0] bits. The SEND control bit is automatically
cleared when the data buffer transmission has ended or by the RFMRST signal. A transmission can be
prematurely interrupted by writing a logical zero to the SEND bit.
7
SEND
0ꢀData transmission ended or transmission not in progress.
1ꢀStart data transmission or transmission in progress.
Buffer Page Select — The RPAGE bit will select the lower or upper 16 bytes of the RFM data buffer when
writing/reading to the RFD0-RD15 registers. This bit also selects between the lower and upper banks of
RFM registers at addresses $0038 through $003B. This bit is cleared by a reset of the MCU.
6
RPAGE
0ꢀSelect the lower 16 bytes of the RFM data buffer.
1ꢀSelect the upper 16 bytes of the RFM data buffer.
End Of Message — The EOM control bit selects whether there will be two data bit times of data 1 carrier
state at the end of each datagram. The EOM control bit is cleared by a RFMRST.
5
0ꢀEOM bit times not added.
1ꢀEOM bit times added.
EOM
FXTH87ERM
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Reference manual
Rev. 5.0 — 4 February 2019
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