HCS08 datasheet(153/290 Pages) MOTOROLA

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Data Sheet — MC9S08GB60/D V1.5

MOTOROLA

153

MC9S08GB/GT

KBEDGn — Keyboard Edge Select for KBI Port Bit n (n = 7–4)

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.

1 = Rising edges/high levels.

0 = Falling edges/low levels.

KBF — 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 logic 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.

1 = KBI interrupt pending.

0 = No KBI interrupt pending.

KBF can be used as a software pollable flag (KBIE = 0) or it can generate a hardware interrupt request

to the CPU (KBIE = 1).

KBACK — Keyboard Interrupt Acknowledge

This write-only bit (reads always return 0) is used to clear the KBF status flag by writing a logic 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.

KBIE — 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.

1 = KBI hardware interrupt requested when KBF = 1.

0 = KBF does not generate hardware interrupts (use polling).

KBIMOD — 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:

•

Rising edges-only or rising edges and high levels (KBEDGn = 1)

•

Falling edges-only or falling edges and low levels (KBEDGn = 0)

1 = Edge-and-level detection.

0 = Edge-only detection.

HCS08 bảng dữ liệu(PDF) 153 Page - Motorola, Inc