BS801B HOLTEK [Holtek Semiconductor Inc], BS801B Datasheet - Page 6

• Manufacturer Part Number: BS801B
• Description: Touch Key
• Manufacturer: HOLTEK [Holtek Semiconductor Inc]

When in the Standby Mode, after a relevant Keyn
wake-up detection has been made, the device will
switch to the Normal Mode and await subsequent switch
detections on all their Keyn pins. It will remain in the Nor-
mal Mode for about 10 seconds for the BS801B and
BS802B devices and for about 20 seconds for the other
devices and if no further detections are made during this
time will return to the Standby Mode.
Rev. 1.00
BS801B and BS802B Operating Flow
BS804B, BS806B and BS808B Operating Flow
6
Touch Key Outputs
All Kout pins have NMOS structures to allow easy inter-
facing to external devices with different operating volt-
ages. The BS801B, BS802 and BS804B devices can
have their outputs configured to operate with either
Level-Hold or Toggle type. The output type is deter-
mined by the status of the LHF pin which is read during
power-on. The logic level on this pin must not be
changed after power on. Internal circuitry ensures that
the internal pull-high resistor on the LHF pin will not
consume current. The BS806B and BS808B only have
Level-Hold output types.
Serial Interface - SCD
Both the BS804B and BS808B are equipped with a sin-
gle line serial interface on the SCD pin, allowing for easy
interfacing to an external MCU.
This single line interface allows communication in both
directions between the touch key device and the external
MCU. Using this interface, the external MCU can serially
read the status of the touch keys at any time. The Serial
interface also allows the external MCU to send com-
mands to the touch key device. The serial interface al-
Part No.
BS801B
BS802B
BS804B
BS806B
BS808B
BS801B/02B/04B/06B/08B
Open
LHF
Low
Level-Hold
Toggle
Level-Hold
Kout Type
July 7, 2009