MC9S08JM16 Datasheet, PDF (122/386 Pages) Freescale Semiconductor, Inc – Microcontrollers

Keyboard Interrupts (S08KBIV2)
KBIP0
1
0 _{S KBIPE0}
KBEDG0
KBIPn
1
0 _{S KBIPEn}
KBEDGn
V_DD
D ^CLR Q
CK
KBACK
RESET
BUSCLK
KBF
SYNCHRONIZER
KBMOD
KEYBOARD
INTERRUPT FF
STOP ^{STOP BYPASS}
KBIE
KBI
INTERRUPT
REQUEST
Figure 8-2. KBI Block Diagram
8.2 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 8-1.
Table 8-1. Signal Properties
Signal
Function
I/O
KBIPn
Keyboard interrupt pins
I
8.3 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 the Memory chapter 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.
8.3.1 KBI Status and Control Register (KBISC)
KBISC contains the status flag and control bits, which are used to configure the KBI.
MC9S08JM16 Series Data Sheet, Rev. 2
122
Freescale Semiconductor