Carrier board sold as open-spec, Cortex-A5 SBC
Jun 30, 2014 — by Eric Brown 1,532 viewsToradex’s “Viola” carrier board extends its Linux-ready Colibri COMs, and ships as a $69 open-spec SBC loaded with its Vybrid-based Colibri VF50 COM.
Swiss embedded vendor Toradex has jumped on the trend of offering carrier boards for its computer-on-modules that can double as sandwich-style, open source single board computers. The Viola board is available separately for $22 ($19 at 1,000+), letting you add any of the eight available Colibri COMs, or you can buy a pre-integrated version installed with the low-cost Colibri VF50 module.


Viola with Colibri VF50 COM (left) and without
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The VF50 incorporates a Freescale Vybrid system-on-chip, but unlike the similar Colibri VF61, which uses VF6x Vybrid model, the VF50 uses the VF5x, which offers only the main Cortex-A5 processor without the VF60’s Cortex-M4 microcontroller. The Cortex-A5, which is also found on Atmel’s SAMA5D3 SoC, is ARM’s most power efficient Cortex-A design, and is often used as a replacement for ARM9 processors. It provides NEON extensions, but no 3D or video accelerators.

Toradex Colibri VF50
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In addition to lacking an MCU, the Colibri VF50 offers a slower, 400MHz version of the Vybrid’s normally 500MHz Cortex-A5 core, and is missing the VF61′s 512KB of L2 cache, A/D converter, and security features. The Colibri VF50 provides Fast Ethernet PHY with IEEE1588 time stamping, and also supplies an RMII interface via the 200-pin SODIMM that enables a second 10/100 port on an attached baseboard.
All other I/O uses the same SODIMM connector, with a wide range of GPIO, UART, I2C, SPI, USB 2.0, SD, camera, S/PDIF, and CAN interfaces, among others. The HMI-targeted, 24-bit LCD interface can handle up to 1024 x 768 resolution, with resistive touch support.
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Aside from the Colibri VF50 and VF61, the Viola board supports the Nvidia Tegra 2-based Colibri T20 and quad-core, Tegra 3-based Colibri T30 modules. You can also choose from four Marvell PXA based ARM/XScale based COMs, including the Colibri PXA320 (IT), Colibri PXA310, the Colibri PXA300 (XT), and the nine-year old Colibri PXA270.
Toradex sells three other carrier boards for its Colibri modules, including a high-end Colibri Evaluation Board, a mid-range, Pico-ITX based Iris, and a lower-end, 160 x 100mm Orchid board. The Viola is the smallest Toradex carrier board yet, measuring just 74 x 74mm. Its main focus is less as a carrier board than as a standalone SBC for small runs of industrial devices.

Viola block diagram
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The Colibri VF50 supplies the Viola with 128MB DDR3 and 64MB DDR3 with ECC, for 192MB RAM total. You also get 128MB NAND flash. The Viola board adds to this with a microSD slot and a resistive touch ready UDI LCD interface, both located on the bottom of the board. Topside you’ll find a 10/100 Ethernet port and dual USB 2.0 ports.
The rest of the I/O is available via onboard connectors. There’s a CAN interface, as well as three serial UARTs, four analog inputs, and GPIO connectors offering a variety of expansion I/O. Toradex has yet to announce the operating temperature range, although the Colibri VF50 COM on its own is available with 0 to 70°C standard and -40 to 85°C on request.


Viola design document, front (left) and back
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Like all the Colibri modules, the VF50 ships with a Linux image, although it also supports Windows Embedded Compact, and even Android. The schematics, layout, open source libraries, and BOM are all available free of charge in electronic format.
Specifications listed for the Viola SBC, which integrates the Colibri VF50 COM, include:
- Processor (via Colibri VF50) –– Freescale Vybrid VF5x (1x Cortex-A5 @ 400MHz); Viola also supports other Colibri COMs
- Memory (via Colibri VF50):
- 128MB DDR3 (16-bit)
- 64MB DDR3 with ECC (8+2-bit)
- 128MB NAND flash (8-bit)
- 1.5MB SRAM (512KB with ECC)
- Memory expansion/storage — MicroSD slot
- Display — Unified Display Interface (LCD) with 4-wire resistive touch
- Networking — 10/100 Ethernet port
- Other I/O:
- 2x USB 2.0 host/device ports
- 3x RS232 UARTs
- 4x analog inputs
- CAN interface
- GPIOs via pinheaders (I2C, SPI, UART A/B/C, GPIOs, PWM)
- Other features — RTC (not assembled); LEDs
- Power — 5VDC voltage with 5V 2A and 3.3V 2A supplies
- Dimensions — 74 x 74mm
- Operating system — Linux image standard; also supports Windows Embedded Compact; Android upon request
Further information
The Viola SBC pre-loaded with the Colibri VF50 COM will be available in July for $69, or $55 per unit for more than 1,000 pieces. The Viola carrier board without the VF50 module will be available at the same time for $22 and $19 (volume). More information may be found at the Viola product page.
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