NXP Semiconductors UM11227 - Page 86

NXP Semiconductors
UM11227
NTM88 family of tire pressure monitor sensors
UM11227 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2020. All rights reserved.
User manual Rev. 6 — 24 April 2020
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3
1
1
2
1
2
aaa-028020
Disabled
Analog powerup
Data ready flag
Continously ON
LFCDF
LFEN = 0 or SRES
(at any state)
LFEN = 1
Frequency error
Sniff for carrier
Increment carrier counter
Carrier counter = LFCC +1
Rise carrier detect flag
Carrier counter ?LFSCC +1
Carrier validated
yes
TOGMOD
TOGMOD
no
No signal above
sensitivity threshold
LFCDTM
not reached
Signal above threshold
AND VALEN = 1
Signal above threshold
AND VALEN = 0
Frequency and
duration check
Rise carrier detect flag
Start analog demode chain
Start timeout
Start analog demod chain
Wait OFF time
(= Tsampling - Ton)
T
PU
= 2 LFO cycles
T
DEC
CARMOD = 1
No SYNC detected
ON time completed
ON time completed
Continously ON
Search for SYNC
Decode ID
Rise ID flag
Rise ID flag
Rise error and EOM flag
Rise data, ready flag
Rise error flag
Rise OVF flags
Decode data
ON time completed
Frequency and
LFCDTM duration check
CARMOD = 0
AND DECEN = 1
CARMOD = 0
AND DECEN = 0
Invert CARMOD
Invert CARMOD
yes
no no
yes
yes
no
no
ONMODE
y
es
ON time completed
yes
Tsampling completed
Switch off
no
yes
no
5 LFO cycles
yes
SYNC detected
Correct ID
Error in first bit
Error Error
Error in first bit
Wrong ID
ID not complete
Timeout
no
Figure 20. NTM88 LFR state machine diagram