PC87413 datasheet(164/257 Pages) NSC

164 / 257 page

9.0 System Wake-Up Control (SWC) (Continued)

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The mouse event detection from MCLK and MDAT is enabled (for event generation) 1 second after the VSB power is on.

This prevents the detection of false events during Mouse VSB power-On transitions. In addition, if the Keyboard/Mouse Pow-

er Control feature (see Section 9.2.10 on page 175) is enabled by setting the VDDFLMUX bit to ‘1’ (in the SIOCF2 register;

see Section 3.7.3 on page 50), mouse event detection is disabled for 2 seconds from the moment the VDD power is turned

off. If this feature is disabled (VDDFLMUX = ‘0’ in SIOCF2) mouse event detection is enabled regardless of the VDD power

status; however, the wake-up becomes effective (VDD power is turned on) only 1 second after the VDD power was turned off.

Keyboard Wake-Up Events

Keyboard wake-up events are also detected by the Keyboard/Mouse Wake-up Detector, which monitors the KBCLK and

KBDAT signals. Since the detection mechanisms for keyboard and mouse events are independent, they can be operated

simultaneously. Moreover, the Keyboard signals may be swapped with the Mouse signals, as explained in the Mouse Wake-

Up Event section (page 163). The Keyboard/Mouse Wake-up Detector is powered by VSB and works independently of the

Keyboard Controller module (powered by VDD).

The keyboard event detection mechanism can be programmed to detect:

Any keystroke (Special Key Sequence mode).

A speciﬁc programmable sequence of up to eight alphanumeric keystrokes (Password mode).

Any programmable sequence of up to eight bytes of data received from the keyboard (Special Key Sequence mode).

Up to three programmable, Power Management keys concurrently available, each including a sequence of up to three

bytes of data received from the keyboard (Power Management Key mode).

The Keyboard/Mouse Wake-up Detector has three operation modes:

Password mode.

Special Key Sequence mode.

Power Management Key mode.

Up to eight Keyboard Data registers (PS2KEY0 to PS2KEY7) are used to define which keyboard data string generates an

event. Since the same set of registers is used by each operation mode, only one mode can be selected at a time.

In the modes involving more than one keystroke, the maximum delay allowed between pressing two consecutive keys is 4

seconds. A longer delay is interpreted by the Wake-up Detector as the beginning of a new sequence of keystrokes, which

causes the present sequence to be discarded. In all operation modes, pressing a wrong key requires a recovery time of 4

seconds, before a new (correct) sequence may be recognized.

Password Mode. In Password mode, the Make and Break bytes transmitted by the keyboard are discarded, and only the

keystroke data bytes are compared with those programmed in the PS2KEY0 to PS2KEY7 registers. If the two sets are equal,

a keyboard event that sets the KBD_EVT1_STS bit in the GPE1_STS_2 register is detected (see Section 9.4.10 on

page 210). The status bit is cleared only when the software writes ‘1’ to it. To simplify the detection mechanism, only keys

with a keystroke data of one byte can be included in the sequence to be detected. To program the Keyboard/Mouse Wake-

up Detector to operate in Password mode, proceed as follows:

1. Set KBDMODE bit in the KBDWKCTL register to ‘0’ (see Section 9.3.16 on page 193).

2. Set KBEVCFG field in the PS2CTL register to a value that indicates the desired number of alphanumeric keystrokes in

the sequence. The programmed value = the number of keystrokes + 7. For example, to detect a sequence of two keys,

set KBEVCFG to 9h.

3. Program the appropriate subset of the PS2KEY0-PS2KEY7 registers in sequential order with the data bytes of the keys

in the sequence. For example, if there are three keys in the sequence and the keystroke data of these keys are 05h (first),

50h (second) and 44h (third), program PS2KEY0 to 05h, PS2KEY1 to 50h and PS2KEY2 to 44h (the scan codes are

only examples).

Special Key Sequence Mode. In Special Key Sequence mode, all the bytes transmitted by the keyboard are compared

with those programmed in the PS2KEY0 to PS2KEY7 registers. These include also the Make and Break bytes. If the two

sets are equal, a keyboard event is detected, as explained in Password Mode, above. This mode enables the detection of

any sequence of keystrokes, including keys as “Shift” and “Alt”. To program the Keyboard/Mouse Wake-up Detector to op-

erate in Special Key Sequence mode, proceed as follows:

1. Set KBDMODE bit in the KBDWKCTL register to ‘0’ (see Section 9.3.16 on page 193).

2. Set KBEVCFG field in the PS2CTL register to a value that indicates the desired number of keystrokes in the sequence.

The programmed value = the number of keystrokes + 1. For example, to detect a sequence of three received bytes (i.e.,

one keystroke), set KBEVCFG to 2h.

3. Program the appropriate subset of the PS2KEY0-PS2KEY7 registers in sequential order with the data bytes that com-

prise the sequence. For example, if the number of bytes in the sequence is four, and the values of these bytes are E0h

(first), 5Bh (second), E0h (third) and DBh (fourth), program PS2KEY0 to E0h, PS2KEY1 to 5Bh, PS2KEY2 to E0h and

PS2KEY3 to DBh (the byte values are only examples).

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