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 SEMTECH
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Send All Keys Send Wake Up Keys Only Send No Keys PWR_OK ↓ PWR_OK ↓ PWR_OK = 0 Soft Reset (PWR_OK =1) AND (WUKO=0) AND (LID=1) AND Key Press (PWR_OK =1) AND Key Press AND (WUKO = 1) WUKO =1 AND Key Press Send XSW Key Only (LID = 0) AND (WUK0=0) AND Key Press (LID = 1) AND (WUKO=0) AND Key Press WUKO=1 AND Key Press PWR_OK ↓ (PWR_OK =1) AND (LID = 0) AND (WUKO=0) AND Key Press Figure 2: The UR5HCSPI implements four modes of keyboard and switch operation. KEYBOARD STATES Copyright Semtech 1997-2001 DOC5-SPI-DS-117 www.semtech.com 7 These states of operation refer only to the keyboard functionality and, although they are related to power states, they are also independent of them. "Send All Keys" Entry Conditions: Power on reset, soft reset, PWR_OK =1, {(LID=1) AND (WUKO=0)} Exit Conditions: PWR_OK = 0 -> "Send No Keys"(WUKO=1) AND (Key Press) -> "Send Wake-Up Keys Only"(LID = 0) AND (WUKO=0) AND (Key Press) -> "Send XSW Key Only" Description: This is the UR5HCSPI’s normal state of operation, accepting and transmitting every key press to the system. This state is entered after the power-on and is sustained while the unit is being used. “Send Wake-Up Keys Only” Entry Conditions:(WUKO=1) AND (Key or Switch press) Exit Conditions: Soft Reset -> “Send All Keys”PWR_OK = 0 -> “Send No Keys” Description:This state is entered when the user turns the unit off. A signal line driven by the host will notify the UR5HCSPI about this state transition. While in this state, the UR5HCSPI will transmit only keys programmed to be wake-up keys to the system. It is not necessary for the UR5HCSPI to detect this transition in real time, since it does not effect any operation besides buffering keystrokes. 3. Stop mode time-out entry will be shortened to further conserve energy. 4. While in this state all interrupts are disabled. The UR5HCSPI will exit this state on the next interrupt event that detects the PWR_OK line has been de-asserted.e “Send XSW Key Only" Entry Condition: (LID=0) AND (WUKO=0) AND (Key Press) Exit Condition: (LID=1) AND (WUKO=0) AND (Key Press) -> “Send All Keys”PWR_OK = 0 -> “Send No Keys” (WUKO = 1) AND (Key Press) -> “Send Wake Up Keys Only” Description: This state is entered upon closing the lid of the device. While in this state, the encoder will transmit only the XSW key, which is located outside the unit. This feature is designed to accommodate buttons on the outside of the box, such as a microphone button, that need to be used while the lid is closed. “Send No Keys" Entry Conditions:PWR_OK transition from high to low Exit Conditions: (PWR_OK = 1) AND (Matrix key pressed OR Switch OR _WKUP) Description: This state is entered when a PWR_OK signal is asserted (transition high to low), indicating a critically low level of battery voltage. The PWR_OK signal will cause an interrupt to the UR5HCSPI, which guarantees that the transition is performed in real time. While in this state, the UR5HCSPI will perform as follows: 1. The LED will be turned off. Nevertheless, its state is saved and will be restored after exiting the disabled state (change of batteries). 2. The UR5HCSPI will enter the STOP mode for maximum energy conservation. |
