NXP Semiconductors
FXTH87E
FXTH87E, Family of Tire Pressure Monitor Sensors
FXTH87ERM
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Reference manual
Rev. 5.0 — 4 February 2019
59 / 183
Q
D
CK
CLR
SYNCHRONIZER
STOP BYPASS
STOP
KBACK
RESET
KBF
KBF
aaa-028003
KBMOD
VDD
BUSCLK
KBIPE0
1
0 S
KBEDG0
KBIPEn
1
0 S
KBEDGn
Figure 15. KBI block diagram
9.4 External signal description
The KBI input pins can be used to detect either falling edges, or both falling edge and low
level interrupt requests. The KBI input pins can also be used to detect either rising edges,
or both rising edge and high level interrupt requests. PTA[3:0] map to KBIPE and KBEDG
function bits [3:0].
The signal properties of KBI are shown in
Table 67
.
Table 67. Signal properties
Signal
Function
I/O
KBIPn
Keyboard interrupt pins
I
9.5 Register definitions
The KBI includes three registers:
•
An 4-bit pin status and control register.
•
An 4-bit pin enable register.
•
An 4-bit edge select register.
9.5.1 KBI status and control register (KBISC)
KBISC contains the status flag and control bits, which are used to configure the KBI.
Table 68. KBI status and control register (address $000C)
Bit
7
6
5
4
3
2
1
0
R
0
0
0
0
KBF
0
W
KBACK
KBIE
KBMOD
Reset
0
0
0
0
0
0
0
0
= Reserved
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