2.1.2.2 Byte Write Enables
(Ask a Question)The byte write enables (A_WEN, B_WEN) enable writing individual bytes of data for x32, x33 and x40 data widths. For x40 width, the byte write enable for the corresponding data is used to enable each of the four bytes; that is, byte write enable for Port A enables A_DIN[19:10] and A_DIN[9:0] and byte write enable for Port B enables B_DIN[19:10] and B_DIN[9:0].
Table 2-7 lists the byte write enable settings for Port A and Port B.
| Depth x Width | A_WEN/B_WEN | Result |
|---|---|---|
| 512 x 32 | B_WEN[0] = 1 | Write B_DIN[8:5], B_DIN[3:0] |
| B_WEN[1] = 1 | Write B_DIN[18:15], B_DIN[13:10] | |
| A_WEN[0] = 1 | Write A_DIN[8:5], A_DIN[3:0] | |
| A_WEN[1] = 1 | Write A_DIN[18:15], A_DIN[13:10] | |
| 512 x 40 | B_WEN[0] = 1 | Write B_DIN[9:0] |
| B_WEN[1] = 1 | Write B_DIN[19:10] | |
| A_WEN[0] = 1 | Write A_DIN[9:0] | |
| A_WEN[1] = 1 | Write A_DIN[19:10] | |
| 512 x 33 (with ECC Enabled) | B_WEN[1:0] = 11 A_WEN[1:0] = 11 | Write B_DIN[16:0] Write A_DIN[15:0] |
Important: For 512x32 configuration, bits 4, 9, 14, and 19 of
data input ports are not used.