mc9s08gt16a Freescale Semiconductor, Inc, mc9s08gt16a Datasheet - Page 102

• Manufacturer Part Number: mc9s08gt16a
• Description: Hcs08 Microcontrollers 8-bit Microcontroller Family
• Manufacturer: Freescale Semiconductor, Inc

Keyboard Interrupt (S08KBIV1)
7.2.1
102
KBEDG[7:4]
KBIMOD
Reset
KBACK
Field
KBIE
KBF
7:4
3
2
1
W
R
KBEDG7
KBI Status and Control Register (KBISC)
Keyboard Edge Select for KBI Port Bits — Each of these read/write bits selects the polarity of the edges and/or
levels that are recognized as trigger events on the corresponding KBI port pin when it is configured as a keyboard
interrupt input (KBIPEn = 1). Also see the KBIMOD control bit, which determines whether the pin is sensitive to
edges-only or edges and levels.
0 Falling edges/low levels
1 Rising edges/high levels
Keyboard Interrupt Flag — This read-only status flag is set whenever the selected edge event has been
detected on any of the enabled KBI port pins. This flag is cleared by writing a 1 to the KBACK control bit. The
flag will remain set if KBIMOD = 1 to select edge-and-level operation and any enabled KBI port pin remains at
the asserted level.
KBF can be used as a software pollable flag (KBIE = 0) or it can generate a hardware interrupt request to the
CPU (KBIE = 1).
0 No KBI interrupt pending
1 KBI interrupt pending
Keyboard Interrupt Acknowledge — This write-only bit (reads always return 0) is used to clear the KBF status
flag by writing a 1 to KBACK. When KBIMOD = 1 to select edge-and-level operation and any enabled KBI port
pin remains at the asserted level, KBF is being continuously set so writing 1 to KBACK does not clear the KBF
flag.
Keyboard Interrupt Enable — This read/write control bit determines whether hardware interrupts are generated
when the KBF status flag equals 1. When KBIE = 0, no hardware interrupts are generated, but KBF can still be
used for software polling.
0 KBF does not generate hardware interrupts (use polling)
1 KBI hardware interrupt requested when KBF = 1
Keyboard Detection Mode — This read/write control bit selects either edge-only detection or edge-and-level
detection. KBI port bits 3 through 0 can detect falling edges-only or falling edges and low levels. KBI port bits 7
through 4 can be configured to detect either:
0 Edge-only detection
1 Edge-and-level detection
0
7
• Rising edges-only or rising edges and high levels (KBEDGn = 1)
• Falling edges-only or falling edges and low levels (KBEDGn = 0)
= Unimplemented or Reserved
KBEDG6
0
6
Figure 7-4. KBI Status and Control Register (KBISC)
Table 7-1. KBISC Register Field Descriptions
KBEDG5
MC9S08GT16A/GT8A Data Sheet, Rev. 1
0
5
KBEDG4
0
4
Description
KBF
3
0
KBACK
0
0
2
Freescale Semiconductor
KBIE
0
1
KBIMOD
0
0