phyCORE-AM3517 Hardware Manual

Part I, Chapter 7: System Memory L-761e_2

7 System Memory

The phyCORE-AM3517 provides three types of on-board memory:

1.

2.

3.

4.

DDR2 SDRAM (U8/U9):

NAND Flash (U16):

EEPROM (U13): from 256MB to 512MB (2x 128MB or 2x 256MB ICs) from 128MB to 512MB from 256KB

The following sections of this chapter detail each memory type used on the phyCORE-AM3517 SOM.

7.1 SDRAM (U8, U9)

The phyCORE-AM3517 is populated with either 256MB or 512MB of 333MHz DDR2 SDRAM configured for 32-bit access using two 16-bit wide RAM chips at U8 and U9.

The AM3517 is capable of addressing 8 RAM banks located at memory address 0x8000 0000. Refer to

Table 7-1 for permissible SDRAM memory access ranges.

Table 7-1. Valid SDRAM Memory Address Ranges

SDRAM Size Lower Memory Address Upper Memory Address

256MB

512MB

0x8000 0000

0x8000 0000

0x8FFF FFFF

0x9FFF FFFF

7.2 NAND Flash (U16)

The NAND memory is comprised of a single 128MB, 256MB or 512MB chip located at U16 and is interfaced via the AM3517 GPMC memory bus.

Write protection control of the NAND device is configurable via jumper J11.

Table 7-2

lists the various

NAND Flash write protection control options, including the default setting on the standard version of the phyCORE-AM3517 SOM included in the Rapid Development Kits (RDK). See below for an overview from the Micron MT29F2G16 datasheet for "Block Lock" and the operation of the LOCK. Refer to this datasheet for information on unlock commands if the LOCK jumper is put in place to protect the NAND flash.

Additionally the "LOCK TIGHT" feature of the NAND flash may be useful in some applications.

The block lock feature protects either the entire device or ranges of blocks from being programmed and erased. Using the block lock feature is preferable to using WP# to prevent PROGRAM and ERASE operations.

Block lock is enabled and disabled at power-on through the LOCK pin. At power-on, if LOCK is LOW, all

BLOCK LOCK commands are disabled. However if LOCK is HIGH at power-on, the BLOCK LOCK commands are enabled. In addition to this, all the blocks on the device are protected or locked from

PROGRAM and ERASE operations, even if WP# is HIGH. Before the contents of the device can be modified, the device must first be unlocked. Either a range of blocks or the entire device may be unlocked.

PROGRAM and ERASE operations complete successfully only in the block ranges that have been unlocked. Blocks, once unlocked, can be locked again to protect them from further PROGRAM and

ERASE operations.

“Blocks that are locked can be protected further, or locked tight. When locked tight, the device's blocks can no longer be locked or unlocked until the device is power cycled."

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