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Dual-core PPC SoC drives 55

Jul 18, 2008 — by Eric Brown — from the LinuxDevices Archive — 8 views

Freescale is sampling a pin-compatible version of its PowerPC-based MPC8641D system-on-chip (SoC) that is claimed to consume 27 percent less power. The 1.0-1.25GHz MPC8640D offers dual e600 cores, a 37 percent lower price, and an optional Linux board support package (BSP), says Freescale.

(Click for larger view of the Freescale MPC8640D)

Freescale appears to have achieved the power and cost reductions by simply slowing down key on-chip clocks. The die size, core voltages, and on-chip peripheral mix appear unchanged from the MPC8641D. Meanwhile, claimed typical power drops to 14-21 Watts, and supported temperature ranges grow to 32 to 221 degrees F (0 to 105 degrees C).

The MPC8640D, and the similar new single-core version, the MPC8640, are designed for networking, telecom, pervasive computing, aerospace, and defense applications, says Freescale. The SoC is said to be “software, package, and pin-for-pin” compatible with the popular MPC8641D PowerQUICC-platform communications processor, which has been used in a number of Linux-compatible single-board computers (SBCs) from Emerson Network Power, Mistral Solutions, Kontron, and others, and has received Linux development support from MontaVista and Wind River.

The new part is also said to be compatible with Freescale's QorIQ SoC, a PowerQUICC heir that is due to start sampling in early 2009.

MPC8640D block diagram (simplified)
(Click to enlarge)

At 1.25GHz, the MPC8640D is clocked lower than the MPC8641D's 1.5GHz maximum, and its much-touted MPX bus scales to only 500MHz instead of 667MHz. Core voltage requirements appear to be unchanged from the MPC8641D, and the core has the same cache sizes — 32KB each of L1 data and instruction cache, and 1MB per core of L2 cache. The SoC also integrates the same AltiVec 128-bit vector processing unit, and the same northbridge functions, including dual DDR1/DDR2 memory controllers, a local bus for connecting storage, and a mix of high-speed interconnects that includes serial RapidIO, Ethernet, and PCI Express.

MPC8640D block diagram (detailed)
(Click to enlarge)

MCEVALHPCN-8641D evaluation board

Freescale is offering one of its “HPCN” Reference Design Board evaluation and development platforms for the MPC8640D. Dubbed the MCEVALHPCN-8641D, the board offers a high-speed SoDIMM slot for each core, and a single PCI-Express slot for graphics or other slot-based expansion cards. It uses the MPC8640's second PCI Express lane to attach a ULI M1575 southbridge.

MPC8641D HPCN reference design board schematic
(Click to enlarge)

The following are some specs for the MPC8641D HPCN board:

  • Processor — MPC8641or MPC8641D (dual core) clocked from 1.0GHz to 1.5GHz
  • Memory — up to 4GB DDRII 600MHz (ECC-compatible)
  • Local bus — 8MB flash; Promjet flash emulator; Actel Pixis FPGA
  • Networking — 4 x 10/100/1000-baseT ports
  • I2C — 2 x I2C buses (one for boot init, and one for DDR SPD EEPROM)
  • Serial — 2 x RS-232 ports
  • High Speed Serial Interface — SerDes Port 1 (configured in x1/x4 PCIe mode connected to ULI southbridge); SerDes Port 2 (x1/x2/x4/x8 PCIe or x1/x4 SRIO mode)
  • Southbridge — ULI 1575 (IDE controller; 2 x USB 2.0; bridge to dual PCI slots)
  • Power supply — dedicated unified VCORE for processor; VTT/VREF for DDR; general I/O power
  • Debug — JTAG/COP via onboard connector
  • Operating system and software — CodeWarrior Linux BSP; U-boot; DINK debugger available

The micro-ATX form-factor board is compatible with either a 1U or 2U rack-mount chassis, and also fits in an ATX/Micro-ATX chassis, says the company. It is preloaded with U-boot and Freescale's CodeWarrior Linux BSP.

Stated Glenn Beck, Freescale's Networking Systems marketing manager, “We expect the MPC8640D to prove especially attractive to markets where power/performance ratios are critical.”


The dual-core MPC8640D (MC8640DVU1000HC) is available at a suggested retail price of $120 in 10K quantities, says Freescale, and the single-core MPC8640 (MC8640HX1000HC) costs $90 in similar quantities. The MPC8641D Reference Design Board (MCEVALHPCN-8641D) sells for $3,075. More information may be found here.

Curtiss-Wright and GE Fanuc both plan to deliver products based on the MPC8640D in the second half of 2008, says Freescale.

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