Texas Instruments TMS320DM647, DM648 DSP manual DDR2 Memory Controller Interface

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Peripheral Architecture

Figure 14. DDR2 SDRAM Column, Row, and Bank Access

Bank 0

Row 0

Row 1

Row 2

Row N

	C	C C		C
	o	o	o	o
	l	l	l	l
0	1	2	3	M

		C C C			C
		o	o	o	o
		l	l	l	l
Bank 1	0	1	2	3	M
Row 0
Row 1
Row 2
Row N

		C	C C		C
		o	o	o	o
		l	l	l	l
Bank 2	0	1	2	3	M
Row 0
Row 1
Row 2
Row N

		C C C			C
		o	o	o	o
		l	l	l	l
Bank P	0	1	2	3	M
Row 0
Row 1
Row 2
Row N

AM is number of columns (as determined by PAGESIZE) minus 1, P is number of banks (as determined by IBANK) minus 1, and N is number of rows (as determined by both PAGESIZE and IBANK) minus 1.

2.7DDR2 Memory Controller Interface

To move data efficiently from on-chip resources to external DDR2 SDRAM device, the DDR2 memory controller makes use of a command FIFO, a write FIFO, a read FIFO, and command and data schedulers. Table 6 describes the purpose of each FIFO.

Figure 15 shows the block diagram of the DDR2 memory controller FIFOs. Commands, write data, and read data arrive at the DDR2 memory controller parallel to each other. The same peripheral bus is used to write and read data from external memory as well as internal memory-mapped registers.

Table 6. DDR2 Memory Controller FIFO Description

		Depth (64-Bit
FIFO	Description	Doublewords)
Command	Stores all commands coming from on-chip requesters	7
Write	Stores write data coming from on-chip requesters to	11
	memory
Read	Stores read data coming from memory to on-chip	17
	requesters

22 DSP DDR2 Memory Controller SPRUEK5A –October 2007

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