MC9RS08KA8RM Datasheet, PDF (64/190 Pages) Freescale Semiconductor, Inc – MC9RS08KA8 Features

Chapter 7 Keyboard Interrupt (RS08KBIV1)
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
INTERRU
PT
Figure 7-1. Keyboard Interrupt (KBI) Block Diagram
7.2 External Signal Description
The KBI input pins can be used to detect falling edges, or both falling edge and low-level-interrupt
requests. The KBI input pins can also be used to detect rising edges, or both rising edge and high level
interrupt requests.
Table 7-1 shows KBI signal properties.
Table 7-1. Signal Properties
Signal
Function
I/O
KBIPn
Keyboard interrupt pins
I
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.
The KBI registers are summarized in Table 7-2.
Table 7-2. KBI Register Summary
Name
KBISC
KBIPE
7
6
5
4
3
2
1
0
R
0
0
0
0
KBF
0
KBIE KBMOD
W
KBACK
R
KBIPE7 KBIPE6 KBIPE5 KBIPE4 KBIPE3 KBIPE2 KBIPE1 KBIPE0
W
MC9RS08KA8 Series Reference Manual, Rev. 3
64
Freescale Semiconductor