UM0804

Block descriptions

Doc ID 16303 Rev 2

9/25

6

Block descriptions

6.1

Dynamic memory subsystem

The Dynamic memory subsystem is composed of three major parts:

6.1.1

Memory chip

The memory used is a Micron DDR2 device and its part number is: MT47H64M16HR-3. Its

size is 128 Mb x 8 (16 Mb x 8 x 8 banks).

6.1.2

Local power supply

It is based on a Monolithic Voltage regulator for the chip set and DDR2/3 (PM6641). It is

generated locally in order to minimize the layout impact and also to avoid any noise injection

between different subsystems.

6.1.3

Signal termination

A parallel termination is added on the clock lines to compensate, if needed, the layout

dissymmetry. Two 100 Ohm resistors are used for each line in order to obtain an impedance

of 50 ohm. All the other terminations are directly inside the pads (both on the SPEAr300 and

the memory sides).

6.2

Static memory subsystem

6.2.1

Serial Flash memory

This block is based on an M25P64 ST Serial Flash memory device. The size of this chip is 8

MB.

A resistor (R8) is also provided to protect the Flash memory from any unwanted write

access.

6.2.2

A resistor (R107) is also provided to protect the EEPROM from any unwanted write access.

6.2.3

NAND Flash memory

This block is based on Nand512W3A2CZA6 ST NAND Flash memory. The size of this chip

is 512 Mbit.

6.2.4

SPI Flash memory

This block is based on the M25P40 ST Serial Flash memory. The size of this chip is 4 Mb.

A resistor (R64) is also provided to protect the Flash memory from any unwanted write

access.