Automotive 2.5D display controllers with 300MHz ARM core

September 24, 2013 // By Graham Prophet
Three new single-chip microcontrollers for 3-inch to 8-inch TFT instrument clusters provide cost-effective 2.5D graphics, hardware PNG decoding and stepper motor control; they support advanced graphics and smaller external memory

Toshiba Electronics Europe has launched three new intelligent display processors for automotive instrument clusters with TFT LCD sizes from (typically) 3-inch to 8-inch. The Capricorn-Bt0, Capricorn-Bt1 and Capricorn-C0 – which use a fast ARM Cortex-R4 core – can manage advanced graphics and conventional stepper motor gauges in hardware from a single IC. In addition, the devices help designers to reduce the external memory needed for image storage.

These Capricorn derivatives combine a ARM Cortex-R4 core running at 300MHz with on-board graphics engines and a built in graphics display controller (GDC). An integrated intelligent stepper motor controller allows each device to also drive needles on speedometers, rev counters and other conventional instrument gauges. All three devices can deliver 3D-style effects without the expense of a 3D GPU.

The Capricorn-Bt0 IC supports a single display, while Capricorn-Bt1 and Capricorn-C0 have two independent display controllers. This suits the Bt1 and C0 for instrument clusters with two displays or, for example, designs that combine a cluster TFT LCD with a head up display (HUD). A built-in ‘2.5D’ graphics accelerator supports key graphics functions such as warping, blitting, scaling, drawing and perspective transformation. The latter makes 3D effects including ‘Cover Flow’ and mirroring possible, realising true perspective viewing. Hardware bitmap rotation with an angle resolution of 0.1° precision combines with high-quality filtering and a patented stroboscope compensation technique for the smooth graphical representation of dials, rapidly rotating pointers and other animations.

Toshiba has expanded the image handling capability of its latest Capricorn processors through support for ‘on-the-fly’ decoding of the high-compression PNG data format. Implementing a multiple stream PNG decoder engine allows direct use of PNG images for graphics operations and direct display. This reduces memory and bandwidth requirements. Use of the MagicSquare dithering unit IP helps to further reduce cost by making it possible to realise perfect dithering of 24-bit graphics on an 18- or 16-bit display.

The new Capricorn devices incorporate a variety