Home Company Blog Comparative Overview: Variscite i.MX6 based SOM Solutions – Part 2

Comparative Overview: Variscite i.MX6 based SOM Solutions – Part 2

By: Liron Kaplan, Konstantin Sinyuk

NXP i.mx6 comparison What's in Part 2 of the article

In part 2 of the article, we will compare core features such as: CPU, Multimedia, Connectivity, Networking, Mechanical Size, Power Consumption, and Operating System while pointing out design limitations where relevant. 
Click here if you missed Part 1.

CPU

As described in the overview section, all of the featured SOMs in this article are equipped with an i.MX6 processor based on ARM® Core. While VAR-SOM-MX6 DART-MX6 VAR-SOM-SOLO/DUAL are equipped with Cortex™-A9, the DART-6UL is based on Cortex™-A7.

However, in each one of the SOMs reviewed in this article, there are a few different CPU options per product which allow further customization and price/performance optimization.
As a starter, the main difference between the CPU configuration options of the DART-6UL is the CPU Clock, which ranges between 528MHz to 900MHz. The relatively new i.MX 6ULL options will allow further price and power consumption optimization, while the i.MX 6UL will add security features on its G2 and G3 options.

The VAR-SOM-SOLO/DUAL can also be optimized with a selection between the i.MX 6S (Single Core, 800MHz in Industrial Grade, 1,000MHz in Commercial Grade) and the i.MX 6DL (DualLite, 800MHz in Industrial Grade, 1,000MHz in Commercial Grade).
The DART-MX6 can be configured with either i.MX 6D (Dual Core, 800MHz) or i.MX 6Q (Quad Core, 800MHz). The VAR-SOM-MX6 which is bigger in mechanical size than the DART-MX6 can be configured with 1200MHz CPU (Dual and Quad core) and 1000MHz CPU in Commercial Grade.

In Industrial grade, the VAR-SOM-MX6 can reach 1000MHz (Dual and Quad) and 800MHz clock speed. As stressed before, the VAR-SOM-SOLO/DUAL, DART-MX6, and VAR-SOM-MX6 are all using the ARM Cortex™-A9 core.

  VAR-SOM-MX6DART-MX6VAR-SOM-SOLO/DUALDART-6UL
CPU
CPU Name NXP i.MX6 NXP i.MX6 NXP i.MX6 NXP i.MX6 Ultralite / i.MX 6ULL
CPU Type Cortex™-A9 MPCore™ Cortex™-A9 MPCore™ Cortex™-A9 MPCore™ Cortex™-A7
CPU Cores 1 - 4 2 - 4 1 - 2 1
CPU Clock (Max) 1.2 GHz 800 MHz 1 GHz 900 MHz
Integer performance (DMIPS) 12000 8000 5000 1955


Memory

All Variscite’s SOM solutions include a variety of memory capacities. For example, while the DART-MX6 uses LP-DDR2, the other three i.MX 6 platforms use DDR3/3L RAM.
The DART-MX6 LP-DDR2 lowers the overall system power consumption and can range between 1GB and 2GB. The VAR-SOM-MX6 supports DDR3 up to 4GB (mainstream up to 2GB), the VAR-SOM-SOLO/DUAL up to 2GB (mainstream up to 1GB), and the DART-6UL up to 1GB (mainstream up to 512MB).

  VAR-SOM-MX6DART-MX6VAR-SOM-SOLO/DUALDART-6UL
Memory
RAM 256 - 4096 MB DDR3 1024-2048 MB LPDDR2 256 - 2048 MB DDR3 128 - 1024 MB DDR3L


On-Board Storage

There are two types of available On-Board storage in the i.MX6 based platforms: SLC NAND and eMMC. The NAND storage is commonly used for Boot loader and OS Boot partition, while the eMMC is used for numerous kinds of user data. Historically, SLC NAND was used for operations that require high reliability such as described above. These days eMMC is a very common and reliable component that is also used by some platforms for booting and has better cost/capacity ratio above 1GB than NAND SLC.

On both the VAR-SOM-MX6 and VAR-SOM-SOLO/DUAL there are configurable options that allow the use of both SLC NAND and eMMC at the same configuration. In each of these SOM products, the eMMC is also completely removable to provide further cost optimization in configurations where significant Flash storage is not required.
Due to DART-6UL small size, only one of these two storage options can be configured per customer selection, ranging from 128MB-512MB SLC NAND, or up to 64GB eMMC. The exception in this area between the i.MX6 SOM products is the DART-MX6, which has no SLC NAND for Flash memory option. Thus, only eMMC is available in various configurations up to 64GB.

  VAR-SOM-MX6DART-MX6VAR-SOM-SOLO/DUALDART-6UL
Storage
Flash Up to 512 MB NAND + 64GB eMMC Up to 64GB eMMC Up to 512 MB NAND
+ 64GB eMMC
Up to 512 MB NAND or 64GB eMMC


Multimedia

In terms of Multimedia features, the DART-6UL is inferior in performance, while VAR-SOM-MX6, DART-MX6, and VAR-SOM-SOLO/DUAL take the lead with enhanced Video Acceleration capabilities. These three SOMs are also equipped with HDMI, LVDS, and DSI interfaces, while the DART-6UL natively supports RGB display only (LVDS can be supported using external RGB -> LVDS bridge).

VAR-SOM-SOLO/DUAL, VAR-SOM-MX6, and DART-MX6 provide both Serial and parallel camera interfaces.
Between these three multimedia-ready SOMs, VAR-SOM-MX6 and DART-MX6 will provide higher-end multimedia performance and 3D capabilities thanks to an improved Graphics Acceleration Unit and higher LVDS resolution. VAR-SOM-SOLO/DUAL multimedia capabilities will be suitable only for applications that require entry level multimedia applications.
On the touch screen options, all four SOMs are very similar. The main difference is the lack of support for internal Resistive Touch on the DART-MX6, which can be added externally to the carrier board.

  VAR-SOM-MX6DART-MX6VAR-SOM-SOLO/DUALDART-6UL
Multimedia
Graphics Acceleration Unit Vivante GC 2000
+ Vivante GC 355
+ Vivante GC 320
Vivante GC 2000
+ Vivante GC 355
+ Vivante GC 320
Vivante GC 880
+ Vivante GC 320
2D pixel acceleration engine (PxP)
Video Acceleration 1080p60 H.264 Decode, 1080p30 H.264 Encode 1080p30 H.264 Decode, 720p H.264 Encode 1080p30 H.264 Decode, 1080p30 H.264 Encode  -
Camera Interfaces 1x CSI, 2x CPI 1x CSI, 1x CPI 1x CSI, 2x CPI 1x CPI
HDMI V1.4 1920 x 1080 V1.4 1920 x 1080 V1.4 1920 x 1080 -
RGB - - - 1366 x 768 24-bit
LVDS Dual 1920 x 1200 24-bit Dual 1920 x 1200 24-bit Dual 1366 x 768 24-bit -
DSI 1280 x 720 24-bit 1280 x 720 24-bit 1280 x 720 24-bit -
Resistive Touch 4-wire Touch External 4-wire Touch 4-wire Touch


Connectivity

All i.MX 6 based modules from Variscite include a wide variety of serial interfaces, supporting multiple UART, SPI, I2C and CAN BUS interfaces. All modules support 2x USB.
The VAR-SOM-SOLO/DUAL, VAR-SOM-MX6, and DART-MX6 also add high-speed PCI-Express, and the VAR-SOM-MX6 and DART-MX6 also support the SATA interface.

  VAR-SOM-MX6DART-MX6VAR-SOM-SOLO/DUALDART-6UL
Connectivity
SD / MMC x1 x1 x1 x1
USB Host / Device USB 2.0: 1x Host, 1x OTG USB 2.0: 1x Host, 1x OTG USB 2.0: 1x Host, 1x OTG USB 2.0: 1x Host, 1x OTG
S-ATA SATA II interface, 3.0 Gbps - - -
UART 5, up to 3.6 Mbps 3, up to 3.6 Mbps 5, up to 3.6 Mbps 8, up to 3.6 Mbps
I2C   x2 x2 x4
SPI x2 x2 x2 x4
CAN Bus x2 x2 x2 x2
ADC - - - 12-bit 2 x 10 channel
One-Wire - - - -
RTC on carrier on carrier on carrier on carrier
PCI-Express Gen 2.0 Gen 2.0 Gen 2.0 -
External Bus EIM EIM - -


Networking

To optimize costs, each one of the SOMs reviewed in this article can be configured and ordered with or without the Wi-Fi/BT and Ethernet PHY (DART-6UL can also support dual ETH).
On VAR-SOM-SOLO/DUAL, VAR-SOM-MX6 and DART-MX6 customers have the option to choose between Single or Dual Band Wi-Fi 802.11a/b/g/n with or without MIMO, all based on TI’s WL183XMOD certified combo module. The DART-6UL includes Single or Dual Band Wi-Fi 802.11ac/a/b/g/n based on LSR/Laird’s Sterling LWB/LWB5 certified combo module.

Each Wi-Fi configuration option selected by the customer will also include Bluetooth supporting BT4.1/BLE.
All of the four SOMs include one or two u.FL connector(s) to enable an easy connection of the customer’s specific antenna(s) for his own specific end product design.

  VAR-SOM-MX6DART-MX6VAR-SOM-SOLO/DUALDART-6UL
Networking
Ethernet 10/100/1000 Mbps 10/100/1000 RGMII 10/100/1000 Mbps 10/100 Mbps + 10/100 RMII
Wi-Fi 802.11 a/b/g/n (MIMO) 802.11 a/b/g/n (MIMO) 802.11 a/b/g/n (MIMO) 802.11 ac/a/b/g/n
Bluetooth 4.1 / BLE 4.1 / BLE 4.1 / BLE 4.1 / BLE


Mechanical size/dimensions

The DART-MX6 is the smallest size between all i.MX6 based platforms. This SOM’s impressive performance in such a small form factor is enabled by an assembly method known as Package on Package (PoP), which assembles the LP-DDR on top of the CPU package. This allows space to be saved on the circuit but limits the available CPU frequency to 800MHz due to power dissipation limitations.

Another small form factor SOM in this group is the DART-6UL, which together with its very low power consumption makes this specific SOM an excellent choice for a Handheld Battery-operated device.
Both VAR-SOM-SOLO/DUAL and VAR-SOM-MX6 arrive in larger dimensions per the table below. It is important to note that these two SOMs are pin2pin. Depending on the entry point requirements of the project, this pin2pin compatibility can allow engineers who find these platforms suitable to their project to define a scalable product line without changing their carrier board and general system design.

  VAR-SOM-MX6DART-MX6VAR-SOM-SOLO/DUALDART-6UL
Mechanical Specifications
Dimensions (W x L x H) 51.5mm x 68mm x 4.5mm 20.0mm x 50.0mm x 4.0mm 35mm x 68mm x 4.5mm 25mm x 50mm x 4.0mm


Operating System

All featured SOMs can work and perform well with a Linux OS (Yocto & Debian). With regards to Android, VAR-SOM-SOLO/DUAL will provide entry level Android support for products requiring a limited number of applications, while the VAR-SOM-MX6 and DART-MX6 are optimal for higher end Android-based products with multiple applications and high-end graphics.

Variscite provides its customers with free access to the BSP/drivers source code.
Complete documentation of the available operating systems with detailed examples can be found inside www.variwki.com.

  VAR-SOM-MX6DART-MX6VAR-SOM-SOLO/DUALDART-6UL
OS Support
Linux Yes Yes Yes Yes
Android Yes Yes Yes Brilo
Windows WEC 7.0 / 2013
(Third Party)
- - -


Additional Features Comparison


  VAR-SOM-MX6DART-MX6VAR-SOM-SOLO/DUALDART-6UL
Audio
Headphone driver Yes Yes Yes Yes
Microphone Digital Digital Digital Analog
Digital audio serial interface S/PDIF S/PDIF S/PDIF SAI, S/PDIF
Line In/Out Yes Yes Yes Yes
Electronic Specifications
Supply voltage 3.3 V 3.3 V 3.3 V 3.3 V
Digital I/O voltage 3.3 V 3.3 V 3.3 V 3.3 V
Temperature Grades
Commercial (0 to 70°C) Yes Yes Yes Yes
Extended (-20 to 70°C) Yes (-20 to 85°C) Yes -
Industrial (-40 to 85°C) Yes Yes Yes Yes

Summary

The goal of this article is to provide technical comparison points that can assist the common developer in choosing the most suitable SOM for his target application and end product.

As described in this article, the main differences between the i.MX6 based SOMs revolve around the range of options in regards to size, power, CPU, multimedia capabilities, and interfaces. That said, each SOM also has numerous configuration options that the customer can select to optimize cost and performance in his specific end product.

Not sure what's the right solution for your project?
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Home Company Blog Comparative Overview: Variscite i.MX6 based SOM Solutions – Part 2