National Semiconductor Mobile I/O Companion Chips

LM8322 and LM8333 mobile I/O companions offers developers an easy way to expand system functionality in portable products such as mobile handsets, media players, PDA, medical equipment and instrumentation. National’s LM8322 and LM8333 mobile I/O companions allow designers to re-partition their systems by offloading tasks from the processor and adding features through a reconfigurable set of simple commands…

The flexible, modular single chips enable use of the same host processor and companion across multiple product versions. The LM8322 and LM8333 off-the-shelf integrated circuits include embedded key-scan functions, I/O expansion and light-emitting diode (LED) control capabilities…

Using the simple command set, the host processor can configure the LM8322 and LM8333 through an I2C compatible ACCESS.bus interface in slave mode up to 400 KHz. The fully tested and qualified companion chips dramatically reduce system design time and maintain accurate performance over the industrial temperature range of -40 degrees C to 85 degrees C.

The LM8322 supports keypad matrices up to 104 keys, while the LM8333 supports up to 72 keys. Both have eight special-function keys that take priority in the key rolling sequence. The on-chip clock, power-on-reset and on-chip oscillator require minimal external circuitry to support the mobile I/O companion's operation….

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