2.1.1.3 Byte Write Enables

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The byte write enables (A_WEN[1:0], B_WEN[1:0]) enable writing individual bytes of data for x20 and x16 widths. The byte write enables for Port A (A_WEN[1:0]) enables A_DIN[19:10] and A_DIN[9:0] respectively. The byte write enables for Port B (B_WEN[1:0]) enable B_DIN[19:10] and B_DIN[9:0] respectively.

The byte write enables are also used in x1, x2, x4, x5, x8, x10, x16, and x20 widths to select the operational mode (read/write) for a Port A or Port B. If all byte write enables are low, then Port A or Port B is considered to be in read mode and any read operations are controlled by the read enables (A_REN/B_REN).

Table 2-5 lists the byte write enable settings for Port A and Port B.

Table 2-5. Byte Write Enables Settings for Dual-Port Mode
Depth x Width	A_WEN/B_WEN	Result
16K x 1, 8K x 2, 4K x 4, 4K x 5, 2K x 8, 2K x 10	00 or 10	Perform a read operation
16K x 1, 8K x 2, 4K x 4, 4K x 5, 2K x 8, 2K x 10	01 or 11	Perform a write operation
1K x 16	00	Perform a read operation
	01	Write [7:0]
	10	Write [17:10]
	11	Write [17:10], [7:0]
1K x 20	00	Perform a read operation
	01	Write [9:0]
	10	Write [19:10]
	11	Write [19:0]