EVE graphics controllers enhance image without impeding bandwidth
Extending its embedded video engine (EVE) offering, Bridgetek has introduced the BT815/6 series of graphic controller ICs. They are designed for human machine interface (HMI) development.
They support the adaptive scalable texture compression (ASTC) algorithm, which means that image quality can be significantly enhanced without needing greater bandwidth to be allocated, says Bridgetek, as the compression algorithm allows for smaller compressed files. The ICs enable major savings in memory space required when it comes to larger fonts and data-heavy images, adds the company.
Memory management and system resource are improved with a dedicated QSPI host port for attaching an external flash memory, to supplement the EVE controller’s on-chip memory. The dedicated port is used exclusively for accessing external memory, extending the on-chip capacity to store additional image and audio objects such as bitmaps and fonts required in feature-rich displays. Used as an additional port, this frees up the main system QSPI port used to control the BT815/816 devices from memory copy tasks and reduces workload on the system MCU.
The BT816 supports displays with four-wire resistive touchscreens and the BT815 is intended for use with capacitive touchscreens and can deliver multi-touch operation (accommodating up to five touch points). Both ICs support the rendering of high resolution (800 x 600) graphics and have video playback capabilities. The built-in hardware engine can recognise touch tags (providing notification for up to 255 tags) and accurately track touch movement. It also supports customised, built-in widgets and functionalities, such as ASTC decode, jpeg decode and calibration.
A programmable interrupt controller allows the devices to generate interrupts corresponding to events such as detecting touch or completing playback of an audio file, without polling the device for responses.
Audio capabilities include a built-in sound synthesiser, plus audio wave playback for mono eight-bit linear PCM, four-bit ADPCM and u-Law sound encoding (at sampling frequencies between 8kHz to 48kHz). Digital filtering has been incorporated to help reduce system design complexity when it comes to external filtering.
The BT815/6 series enables engineers to construct feature-rich HMIs, with graphic control, audio control and touch control interfaces, without prior experience.EVE’s object-based architecture reduces the hardware needed for HMI implementation, says Bridgetek, eliminating both the frame buffer and large flash memory normally required, using instead the internal 1Mbyte graphics RAM. It also means that a less complex, lower cost MCU can be used within the HMI design, to reduce the overall bill of materials.
The BT815 and BT816 EVE devices are both supplied in 64-pin VQFN packages. They have an extended operational temperature range covering -40 to +85°C.
