I/O expanders increase functionality and reliability in mobile handset designs

Additionally, the TC35893XBG and TC35894XBG improve power efficiency in handheld devices and address the mechanical and electrical design challenges associated with moveable parts in advanced-feature mobile handsets.

With today’s mobile handsets offering everything from Internet access and text messaging to multimedia storage and playback, 3D gaming, mobile TV and video capture, additional I/O ports are required to accommodate the peripherals needed to support these applications. Moreover, to facilitate easier keyboard operation, slide-out and clam-shell configurations have become quite popular; but these types of handheld implementations present challenges because heavy wiring through the hinges and sliders can cause electromagnetic interference (EMI) and mechanical stress, which can result in product failure. The TC35893XBG and TC35894XBG I/O expanders solve these problems by dramatically reducing the wired connections in moveable handheld designs while still providing full flexibility to accommodate various keypad layouts from 2x2 to 8x12 with up to 96 keys. Safe detection of single keys (20 in TC35893XBG, 26 in TC35894XBG) is available in both devices. All I/O can act as interrupt inputs.

Toshiba continues to stay abreast of issues in handheld designs and will quickly develop and release solutions for mobile peripheral devices that interface between the baseband and/or application processors to I/O devices such as cameras, displays, keypads and touch panels. The TC35893XBG and TC35894XBG expand Toshiba’s previous I/O expander products by adding support for both direct CMOS clock and internal RC-generated clock input and adding a more flexible debounce period to further strengthen Toshiba’s Mobile Strategic Initiative to facilitate feature-rich cell phones, smart phones, PMPs, PNDs and gaming handhelds.