Vim4 SBC with up to 8GB RAM rides octa-core Amlogic A311D2

Vim4 SBC with up to 8GB RAM rides octa-core Amlogic A311D2

Oct 23, 2021 — by Eric Brown

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Khadas is prepping a “Khadas Vim4” SBC that runs Linux on a new, octa-core -A73 and -A53 Amlogic A311D2 SoC with support for 16GB RAM. The Vim4 offers 8GB RAM, 802.11ax, dual CSI links, and a micro-HDMI 2.1 input.

Shenzhen Wesion’s Khadas project has announced an upgrade of its open-spec Khadas Vim3 SBC with Amlogic’s new octa-core A311D2 in place of the Vim3’s hexa-core A311D. The Khadas Vim4 has the same footprint and much the same layout and feature set, but it boosts the RAM support to 8GB and adds Wi-Fi 6 and several new media interfaces.

Khadas Vim4 (left) and Khadas Vim3
(click images to enlarge)
(Source: Vim4 image from CNXSoft)

Amlogic A311D2

The Amlogic A311D2 adds two more Cortex-A53 cores to the A311D design for 4x -A53 cores that are now clocked at up to 2.0GHz instead of 1.8GHz. The 4x Cortex-A73 cores remain clocked at 2.2GHz. Amlogic continues to use a 12nm process.

The A311D2 upgrades from an Arm Mali-G52 MP4 GPU to a Mali-G52 MP8 (8EE). The 11th Gen Advanced Amlogic TruLife Image Engine supports 8Kp24 AV1 video decoding. The SoC adds support for eDP, LVDS, and the SerDes derived LVDS alternative V-by-One, which runs faster over twisted-pair copper lines.

Amlogic A311D2 preliminary block diagram
(click image to enlarge)
(Source: Khadas)

In addition to providing the previous MIPI-DSI and HDMI 2.1 outputs, the SoC can now drive 3x HDMI 2.1 inputs at up to 4Kp60. An improved 16MP ISP enables 4K video encoding (H.265/H.264 at 4Kp50) and enables the Vim4 to add a second 4-lane MIPI-CSI interface.

The other major improvement is a boost in RAM support to up to 16GB LPDDR4/X clocked at a higher 2133 MHz. There is also a dedicated USB 3.0 interface instead of being multiplexed with PCIe, so you can use both at the same time. Once again, you get GbE MAC and 10/100 PHY and support for USB 2.0 with OTG.

The Amlogic A311D2 has yet to show up on Amlogic’s website. However, the CNXSoft post that alerted us to the processor links to a preliminary reference manual (PDF). We saw no mention in the manual of the up to 5-TOPS NPU found on the A311D, although CNXSoft says the NPU is listed as TBD (to-be-decided), “possibly due to license requirements.” There is mention of an optional dual-core HiFi 5 audio DSP with Neural Network Extensions for audio/voice processing.

In addition to powering the Khadas Vim3, the A311D was used in Geniatech’s DB10 and Orbbec’s Zora P1 dev kits.

Khadas Vim4

Just as the A311D2 is an incremental, although rather major, upgrade of the A311D, the Khadas Vim4 plays the same role in comparison to the Vim3. Khadas has yet to post a product page or announcement, but CNXSoft has posted preliminary specs. There was no mention of price or availability.

The Khadas Vim4 keeps the 82 x 58mm dimensions and many of the same features. It offers double the RAM of the Vim3 — although half the A311D2’s limits — with 8GB LPDDR4X @ 2112 MHz. The Vim4 adds double the SPI flash with 32MB and the Cortex-M4 MCU has been replaced with a lower-power, Cortex-M0+ based STM32G031 dedicated to power management.

The Vim4 adds eDP, LVDS, and V-By-One interfaces alongside the previous HDMI 2.1 and DSI outputs, and the HDMI port supports 8Kp24 AV1. There is a new micro-HDMI 2.1 input port at up to 4Kp60 and a second 4-lane CSI interface. The 802.11ac/BT 5.0 radios have been upgraded to 802.11ax with BT 5.2 via an Ampak 6275S module

Continuing features include GbE, USB Type-C OTG, and 2x USB 3.0 host ports. Once again there is a microSD slot, 40-pin GPIO, and an M.2 2280 socket lets you load NVMe modules. Presumably, the Vim4 supports the same Khadas Vim accessories. Other unchanged features include an RTC, IR, an accelerometer, and a 5-20V input.

OS support will likely match that of the Vim3, which currently includes Ubuntu 20.04 LTS with Linux 4.9. Third-party images include Armbian, LibreELEC, CoreELEC, Manjaro, and Android.

Further information

No pricing or availability information was provided for the Khadas Vim4 or Amlogic A311D2. More on the SBC should eventually show up on the Khadas website.
More on the A311D2 may be found in Amlogic’s A311D2 reference manual (PDF).