HD64F2149YV datasheet(591/1075 Pages) RENESAS

591 / 1075 page

Section 17 Keyboard Buffer Controller

Rev. 3.00 Jan 18, 2006 page 563 of 1044

REJ09B0280-0300

Bit 5—Keyboard Data In (KDI): Monitors the KDI I/O pin. This bit cannot be modified.

Bit 5

KDI

Description

KD I/O pin is low

KD I/O pin is high

(Initial value)

Bit 4—Keyboard Buffer Register Full Select (KBFSEL): Selects whether the KBF bit is used

as the keyboard buffer register full flag or as the KCLK fall interrupt flag, When KBFSEL is

cleared to 0, the KBE bit in the KBCRL register should be cleared to 0 to disable reception.

Bit 4

KBFSEL

Description

KBF bit is used as KCLK fall interrupt flag

KBF bit is used as keyboard buffer register full flag

(Initial value)

Bit 3—Keyboard Interrupt Enable (KBIE): Enables or disables interrupts from the keyboard

buffer controller to the CPU.

Bit 3

KBIE

Description

Interrupt requests are disabled

(Initial value)

Interrupt requests are enabled

Bit 2—Keyboard Buffer Register Full (KBF): Indicates that data reception has been completed

and the received data is in the keyboard data buffer register (KBBR).

Bit 2

KBF

Description

[Clearing condition]

(Initial value)

Read KBF when KBF =1, then write 0 in KBF

[Setting condition]

• When data has been received normally and has been transferred to KBBR

(keyboard buffer register full flag)

• When a KCLK falling edge is detected (while KBFSEL = 0) (KCLK interrupt flag)

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