NXP Semiconductors
FXTH87E
FXTH87E, Family of Tire Pressure Monitor Sensors
FXTH87ERM
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Reference manual
Rev. 5.0 — 4 February 2019
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5.5.4.10 LFR
When the LFR is enabled and the MCU enters STOP mode, the detectors in the LFR will
remain powered up depending on the states of the bits selecting the periodic sampling.
Refer to
Section 14 "LF Receiver"
for more details.
5.5.4.11 Band gap reference
The band gap reference should be enabled whenever the sensor measurement interface
requires sensor or voltage measurements.
5.5.4.12 TPM1
When the MCU enters STOP mode, the clock to the TPM1 module stops and the module
halts operation. If the MCU is configured to go into STOP1 mode, the TPM1 module will
be reset upon wakeup from STOP and must be re-initialized.
5.5.4.13 Voltage regulator
The voltage regulator enters a low-power standby state when the MCU enters any of the
STOP modes except STOP4 (LVDSE = 1 or ENBDM = 1).
5.5.4.14 Temperature sensor
The temperature sensor is powered up on command from the MCU.
5.5.4.15 Temperature restart
When the MCU enters a STOP mode, the temperature restart will remain powered up if
the TRE bit is set. If the temperature restart level is reached, the MCU will restart from
the reset vector.
5.5.5 RFM module in STOP modes
The RFM’s external crystal oscillator (XCO), bit rate generator, PLL, VCO, RF data
buffer, data encoder, and RF output stage will remain powered up in STOP modes during
a transmission, or if the SEND bit has been set and DIRECT mode has been enabled.
5.5.5.1 RF output
When the RFM finishes a transmission sequence the external crystal oscillator (XCO), bit
rate generator, PLL, VCO, RF data buffer, data encoder, and RF output stage will remain
powered up if the SEND bit is set.
5.5.6 P-cell in STOP modes
The P-cell is powered up only during a measurement if scheduled by the sensor
measurement interface. Otherwise it is powered down.
5.5.7 Optional g-cell in STOP modes
The g-cell is powered up only during a measurement if scheduled by the sensor
measurement interface. Otherwise it is powered down.
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