NXP Semiconductors
FXTH87E
FXTH87E, Family of Tire Pressure Monitor Sensors
Table 122.ꢀLFCTRLE register field description
Field
Description
7-3
Reserved bits — Not for user access.
Reserved
LOGAMP AZ Sequencer Control — Control bits for AZ and trim within the LOGAMP.
X00 Nominal AZ sequence — recommended setting
X01 Short amp output release, max delay with Rects
X10 Short amp output release, max delay with Amp input
X11 All short, max delay with end of AZ
2-0
AZSC
0XX Nominal sensitivity trim — recommended setting
1XX Sensitivities shifted by — 4 trim steps
14.17.8 LFR control register D (LFCTRLD, LPAGE = 1)
The LFCTRLD register contains two control bits for the LF detector and decoder. It is
only accessible when the LPAGE bit is set.
Table 123.ꢀLFR control register D (LFCTRLD, LPAGE = 1) (address $0022)
Bit
R
7
6
5
4
3
2
ONMODE
0
1
0
DEQS
AVFOF[1:0]
AZDC[1:0]
CHK125[1:0]
W
Reset
0
0
0
0
0
0
0
= Reserved
Table 124.ꢀLFCTRLD register field descriptions
Field
Description
SUM AZ release delay — Control the delay between falling edge of SUM d_az_en input and falling edge of
internal AZ control line.
00ꢀNo delay
7-6
01ꢀNo delay
AVFOF[1:0]
10ꢀOne-half of 125 kHz clock period delay — recommended setting
11ꢀOne and one-half of 125 kHz clock periods delay
DeQing status register — This read-only status bit allows the reading of the effective activation of the
DeQing System.
5
0ꢀDeQing system not activated
1ꢀDeQing system activated
DEQS
AZ Digital Control of AZ triggering — In data receive mode, this bits control the triggering of AZ sequence
with respect to both LFCPTAZ value (ref. LFCTRLB register) and the state of the demodulation input data
state.
00ꢀAZ starts after LFCPTAZ numbers of input data edges.
4-3
01ꢀZ starts randomly adding –1, 0 or 1 to LFCPTAZ value between each AZ.
10ꢀAZ starts after LFCPTAZ numbers of input data edges and when the input data (d_data) state is 0.
AZDC[1:0]
11ꢀAZ starts after LFCPTAZ numbers of input data edges and when the input data (d_data) state is 1 —
recommended setting.
FXTH87ERM
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Reference manual
Rev. 5.0 — 4 February 2019
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