Ddr2 Memory Interface - Spectrum Digital TMS320DM6437 Technical Reference

Spectrum Digital, Inc
2.1 EMIF Interfaces
A separate 8 bit EMIF with multiple chip selects divide up the address space and allow
for asynchronous accesses on the EVM. On board the CS2 is used for Flash, NAND
Flash, or SRAM.

2.1.1 DDR2 Memory Interface

The DM6437 device incorporates a dedicated 32 bit wide DDR2 memory bus. The
EVM uses two 512 megabit 16 bit wide memories on this bus, for a total of 128
megabytes of memory for program, data, and video storage. The internal DDR
controller uses a PLL to control the DDR memory timing. The interface supports rates
up to 166 Mhz., and is clocked on differential edges for optimal performance. Memory
refresh for DDR2 is handled automatically by the DM6437 internal DDR controller.
2.1.2 Flash, NAND Flash, SRAM Memory Interface
The DM6437 has 16 megabytes of NOR Flash, or 64 megabytes of NAND Flash, or
2 megabyte of SRAM memory mapped into the CS2 space. This NOR Flash memory,
and NAND Flash memory are used primarily for boot loading. SRAM is used for
debugging application code. The CS2 space is configured as 8 bits wide on the
DM6437 EVM for NOR Flash, SRAM, or NAND flash usage.
2.2 Peripheral Interfaces
The DM6437 has several peripheral interfaces which allow the user to interface to
external devices. These interfaces are outlined in the following sections.
2.2.1 VLYNQ Interface
The DM6437 brings its internal VLYNQ interface out to a mini PCI connector J20 and
small 20 pin connector DC_P3. The VLYNQ interface is multiplexed on the PCI/EM bus
and this bus must be reconfigured after boot up to support VLYNQ. A multiplexer is
used to minimize board layout stubs and allow as direct as possible interface for the
VLYNQ signals. VLYNQ is not operational if the board is used in a PCI slot.
2.2.2 UART Interface
The internal UART0 on the DM6437 device is driven to connector P8. The UART's
interface is routed to a Texas Instruments MAX3221 RS-232 line driver prior to being
brought out to a male DB-9 connector, P8. The on board UART signals can be disabled
by pulling the RS232_ENABLEn signal high via the daughter card connectors.
2-2 DM6437 EVM Technical Reference