APU Targets Embedded Applications
G-Series block diagram
Bobcat core block diagram
G-Series chip
G-Series Mini-ITX
AMD has targeted the embedded space on and off for many years. It is taking aim at Intel's popular Atom processor with the new 40nm AMD G-Series. The G-Series, code named eBrazos, (Fig. 1) features one or two x86 "Bobcat" cores (Fig. 2) along with dual SIMD engines that can be utilized for computation or for graphics. These engines are the heart of the on-chip GPU that support DX11 graphics, 3D processing and includes a unified video decoder that handles H.264, VC1, and DivX/Xivd. They can be programmed using OpenCL and OpenGL. AMD refers to the the G-Series chips as an APU (accelerated processing unit). It comes in 9W and 18W TDP versions in both single and dual core. The Bobcat core is capable of sub 1W operation using clock and power gating along with low power system states.
| Model | Clock | Cores | Graphics | Max TDP |
|---|---|---|---|---|
| T56N | 1.6 GHz | 2 | AMD Radeon HD 6310 | 18W |
| T48N | 1.4 GHz | 2 | AMD Radeon HD 6310 | 18W |
| T40N | 1.0 GHz | 2 | AMD Radeon HD 6250 | 9W |
| T52R | 1.5 GHz | 1 | AMD Radeon HD 6310 | 18W |
| T44R | 1.2 GHz | 1 | AMD Radeon HD 6250 | 9W |
Each 64-bit core has a 32 Kbyte instruction and data cache. The per core L2 cache is 512 Kbytes. It uses out-of-order execution with a dual instruction decoder and an advanced branch predictor. They support AMD"s AMD-V virtualization technology.
The 413 ball BGA chip (Fig. 3) is only 361 mm2 (19mm by 19mm). It has a 64-bit, 1066 MHz DDR3 interface that supports a pair of DDR3 DIMMs. The graphics controller can handle a pair of interfaces that can handle HDMI, DVI or Display Port. It also supports a single linked LVDS display. It can handle 1080p playback and resolutions up to 2560 by 1600.
The "Hudson" Fusion hub controller comes in a 23mm by 23mm BGA package with 605 balls. The controller adds a 4 x1 or 1 by 4x PCI Express interface. It supports 6 SATA ports, CIR, LPC, SPI, 14 USB 2.0 ports and hi-def audio. It also has 102 GPIOs. The A55E version has a Gigabit Ethernet port, RAID 0/1/5/10 support and a 33MHz PCI interface. The chip connects to the APU using AMD's unified media interface. The chip consumes from 2.7W to 4.7W.
AMD is looking to provide embedded developers with a range of support options and reference designs. I was able to check out a system based on their Mini-ITX board (Fig. 4) although mine was fanless. The AMD DB-FT1 development board is great for digital signage, set top box and thin clients. It is available with the AMD A55E controller hub with PCI and Gigabit Ethernet support. The test system I worked with was running Windows 7 and had DVI and VGA video outputs. Overall, the system was very capable when connected to an HDTV. It could stream 1080p from my MythTV server. Being fanless, it was absolutely quiet.
The incorporation of PCI Express on the APU will allow the chip to be used without the hub controller. This will be key to many embedded applications as the hub controllers typically provide PC-style interfaces. This puts it on par with the Intel E6xx processors although AMD's PCI Express interface is more flexible.
