Low-power MCU in drive for display applications

Edited by the Electronicstalk editorial team Feb 11, 2002

Sunrise Electronics has a new microcontroller from NEC combining extremely low power consumption and low voltage supply requirements with an onboard LCD driving capability.

Sunrise Electronics has a new microcontroller from NEC combining extremely low power consumption and low voltage supply requirements with an onboard LCD driving capability ideal for remote control applications, instrumentation and consumer medical equipment.

Many handheld designs incorporate LCD information displays demanding additional components to achieve good readability.

Now Sunrise is introducing the uPD789488, a new member of NEC's successful low-power 78K0S 8bit family, which features an on-chip voltage booster to drive high contrast LCD, as well as integrating many other on-chip functions.

In addition to the 112-segment (28 x 4), LCD controller/driver, the uPD789488 includes a two channel serial interface (one with automatic transfer ability), a key return signal detector, six timer channels, one of which includes a carrier generator that can easily be used to provide output waveforms for infra-red remote control.

Additional signal processing capability is provided by an on chip eight-channel, 10bit A/D convertor and an onboard 8 x 8bit multiplier with 16bit result.

Up to 45 I/O ports are available of which four are N-channel open-drain outputs.

Onboard memory includes 32Kbyte of program ROM, 1024byte of internal high speed RAM plus 28byte of LCD RAM.

A variant with Flash program memory is also available.

Minimum instruction execution time can be selected between high speed (0.4us at 5.0MHz operation with main system clock), low speed (1.6us at 5.0MHz operation with main system clock), and ultra low speed (122us at 32.768kHz operation with subsystem clock).

This enables the appropriate trade off between speed and power consumption to be chosen.

A circuit to multiply the subsystem clock by four is selectable by a mask option (giving 15.26us at 131kHz operation with a standard 32.768kHz subsystem clock x4).

Designed to operate from a low voltage supply of 1.8 to 5.5V, these devices are supplied in 80-pin PQFP (14 x 14mm) or the very fine pitch TQFP (12 x 12mm) outlines for surface mounting, making them ideal for compact designs.