NXP Semiconductors MC9S08LG16, Reference Manual

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Chapter 7 Keyboard Interrupt (S08KBIV2)
MC9S08LG32 MCU Series, Rev. 5
Freescale Semiconductor 131
Figure 7-2. KBI Block Diagram
7.2 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.
The signal properties of KBI are shown in Table 7-2 .
7.3 Register Definition
The KBI includes three registers:
• An 8-bit pin status and control register.
• An 8-bit pin enable register.
• An 8-bit edge select register.
Refer to the direct-page register summary in Chapter 4, “Memory ,” for the absolute address assignments
for all KBI registers. This section refers to registers and control bits only by their names.
Some MCUs may have more than one KBI, so register names include placeholder characters to identify
which KBI is being referenced.
7.3.1 KBI Status and Control Register (
KBI
SC)
KBISC contains the status flag and control bits, which are used to configure the KBI.
Table 7-2. Signal Properties
Signal Function I/O
KBIPn Keyboard interrupt pins I
D Q
CK
CLR
V
DD
KBMOD
KBIE
KEYBOARD
INTERRUPT FF
KBACK
RESET
SYNCHRONIZER
KBF
STOP BYPASS
STOP
BUSCLK
KBIPEn
0
1
S
KBEDGn
KBIPE0
0
1
S
KBEDG0
KBI
P0
KBI
Pn
KBI
INTERRUPT
REQUES
T