MC9S08QG8 Datasheet, PDF (177/300 Pages) Freescale Semiconductor, Inc – 8-BIT HCS08 Central Processor Unit

Keyboard Interrupt (S08KBIV2)
12.3 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 and relative address
offsets.
Some MCUs may have more than one KBI, so register names include placeholder characters to identify
which KBI is being referenced.
12.3.1 KBI Status and Control Register (KBISC)
KBISC contains the status flag and control bits, which are used to configure the KBI.
7
6
5
4
3
2
1
0
R
0
0
0
0
KBF
0
KBIE
KBMOD
W
KBACK
Reset:
0
0
0
0
0
0
0
0
= Unimplemented
Figure 12-3. KBI Status and Control Register
Table 12-2. KBISC Register Field Descriptions
Field
Description
7:4 Unused register bits, always read 0.
3
Keyboard Interrupt Flag — KBF indicates when a keyboard interrupt is detected. Writes have no effect on KBF.
KBF 0 No keyboard interrupt detected.
1 Keyboard interrupt detected.
2
Keyboard Acknowledge — Writing a 1 to KBACK is part of the flag clearing mechanism. KBACK always reads
KBACK as 0.
1
KBIE
Keyboard Interrupt Enable — KBIE determines whether a keyboard interrupt is requested.
0 Keyboard interrupt request not enabled.
1 Keyboard interrupt request enabled.
0
Keyboard Detection Mode — KBMOD (along with the KBEDG bits) controls the detection mode of the keyboard
KBMOD interrupt pins.0Keyboard detects edges only.
1 Keyboard detects both edges and levels.
12.3.2 KBI Pin Enable Register (KBIPE)
KBIPE contains the pin enable control bits.
MC9S08QG8 and MC9S08QG4 Data Sheet, Rev. 1.01
Freescale Semiconductor
177