| XC3000 | XC4000E | XC4000X | XC5200 | XC9000 | Spartan | SpartanXL | Virtex |
|---|---|---|---|---|---|---|---|
| N/A | Macro | Macro | N/A | N/A | N/A | N/A | N/A |
RAM16X8 is a 16-word by 8-bit static read-write random access memory. When the write enable (WE) is High, the data on data inputs (D7 - D0) is loaded into the word selected by the 4-bit address (A3 - A0). The data outputs (O7 - O0) reflect the selected (addressed) word, whether WE is High or Low. When WE is Low, the RAM content is unaffected by address or data input transitions. Address inputs must be stable before the High-to-Low WE transition for predictable performance.
The initial contents of RAM16X8 cannot be specified directly. Initial contents may be specified only for RAMs that are 1-bit wide and 16 or 32 bits deep. See “Specifying Initial Contents of a RAM” in the “RAM16X1” section.
Mode selection is shown in the following truth table.
| Inputs | Outputs | |
|---|---|---|
| WE(mode) | D7 - D0 | O7 - O0 |
| 0(read) | X | Data |
| 1(write) | D7 - D0 | Data |
| Data = word addressed by bits A3 - A0 | ||
Figure 9.3 RAM16X8 Implementation XC4000 |  |
