Auto Electronics

Freescale instrumentation cluster MCU features on-chip TFT display driver

Freescale Semiconductor is sampling a 16-bit microcontroller designed especially for use in automotive instrumentation clusters. The MC9S12XHZ512 features a 40 MHz enhanced 16-bit HCS12 CPU core; an XGATE coprocessor module; 512 KB of on-chip flash memory (twice that of its S12HZ predecessor); up to 12 KB RAM and 2 KB EEPROM; a 32 x 4 LCD drive, and six XYZ stepper motor drives for use with gauges. The stepper motor drives include stall detection circuitry that would otherwise require external logic.

The XGATE module, which features a RISC architecture and C language programmability, runs at twice the speed of the main processor and can boost system performance by as much as 80 MIPS, according to Mark Renucci, product marketing manager for 16-bit automotive MCUs.

The XGATE includes a programmable DMA controller, a real-time interrupt handler, and a virtual peripheral controller, and is capable of driving a 30,000-pixel thin film transistor (TFT) or vacuum fluorescent display (VFD) directly, thus eliminating the need for an external graphics accelerator chip and lowering system cost by $2 to $4, according to Freescale. With the addition of a low-cost 100K-gate FPGA, the XGATE can drive a quarter video graphics array (QVGA). The S12XHZ512 can also drive analog gauges and light-emitting diode (LED) displays.

“There is a trend toward displaying more information in more attractive ways on the dashboard as a means of differentiation, and TFT displays are gaining momentum in the mainstream automotive market,” Renucci said. “Drivers have a strong connection with the dashboard, and automakers are putting a lot of focus on it.” He added that the MC9S12XHZ512 enables engineers to reduce the complexity of instrumentation cluster designs while implementing high-quality graphic displays on lower-end automotive dashboards in a timely, cost-effective manner.

The S12XHZ512 is based on the S12X core and is pin-compatible with earlier members of the S12HZ family and code-compatible with member of the HCS12 family.

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