Solution Description
A new trend in today's vehicles calls for several auxiliary displays to complement the main infotainment system. The additional displays offer extended infotainment features in rear seats, for example, and for basic control functions replacing standard buttons, knobs, and levers used for adjusting the position of seats, mirrors, or headlights.
The solution is a handy way to rapidly implement touch controls for in-vehicle media, climate control, and other interior controls using swipe and tap gestures similar to a smartphone.
Developed inside our AutoDevKit ecosystem, it is a flexible turnkey solution with customizable firmware for managing several different GUIs.
How does it work?
Our AutoDevKit plugin library for SPC5-STUDIO (STSW-AUTODEVKIT) consists of several software plugins including one is dedicated to driving LCD touchscreens via an automotive-grade 32-bit general-purpose SPC58 microcontroller. The SPC58 microcontroller communicates with each LCD touchscreen via an SPI module in one of two configurations:
a single module can be dedicated to driving the touchscreen while a second one is used to decode the information displayed on the touchscreen
a single module with two Chip Select pins can be used to drive a touchscreen and decode display data
The maximum size of the LCD is limited by the maximum bandwidth of the SPI protocol. For larger sizes, parallel communication protocols such as HDMI are required. (In this case, we recommend using our Accordo family of STA1x infotainment processors.) The maximum number of LCDs connectable to the MCU depends upon the number of the SPI ports available in the microcontroller. To optimize your implementation, the software driver in the AutoDevKit plugin has an option to use the same SPI port for both driving the touchscreen and decoding the information displayed.
The same considerations must be taken into account concerning each of the LCD's refresh rate. In certain real-time systems, it is preferable to dedicate a specific core present in the MCU to driving the LCD to prevent the real-time system from being limited by the LCD refresh rate. For example, when using a general-purpose dual-core SPC58EC microcontroller, one core can be dedicated to motor control while the other one is used to drive the LCD touchscreen.
While the software driver provides 2D functions for basic geometry figures and includes a set of fonts that can be loaded and displayed on the touchscreens, developers must take into consideration the amount of Flash memory available because each font will occupy some of it.
Choosing the most effective SPC58 microcontroller for your application
| SPC58 MCU | Number of cores | Number of SPI ports | Additional communication interfaces | Flash memory size | Other key features |
|---|---|---|---|---|---|
| SPC58 2B Line | Single (80 MHz) | 4 DSPI ports |
| Up to 1 Mbyte | Boot-assist Flash |
| SPC58 4B Line | Single (120 MHz) | 7 DSPI ports | 1 Ethernet controller (10/100 Mbps) | Up to 2 Mbytes | Boot-assist Flash; Nexus Development Interface (NDI) |
| SPC58 C Line | Single (180 MHz); Dual (180 MHz) | 8 DSPI ports | 1 Ethernet controller (10/100 Mbps) Dual-channel FlexRay controller | Up to 6 Mbytes | Boot-assist Flash; Nexus Development Interface (NDI) |
| SPC58 G Line | Single (180 MHz); Dual (180 MHz); TrIple (180 MHz) | 10 DSPI ports | 1 Ethernet controller (10/100 Mbps) Dual-channel FlexRay controller | Up to 8 Mbytes | Boot-assist Flash; Nexus Development Interface (NDI) |
| SPC58 H Line | TrIple (200 MHz) | 10 DSPI ports | 2 Ethernet (with one 1 Gbps), 16 ISO CAN FD and 24 LIN interfaces | Up to 10 Mbytes | Boot-assist Flash; Nexus Development Interface (NDI) |
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All Features
- Complement main infotainment system with additional LCD touchscreens
- The same hardware module can be reused for different applications in the vehicle just by changing the software, i.e., no need for customized physical buttons (further reducing BOM costs)
- It creates a companion for system debugging of embedded systems
- Re-use of SPI modules for a simple and common MCU communication protocol instead of dedicated and more expensive ports
