RAM16X8S

16-Deep by 8-Wide Static Synchronous RAM

RAM16X8S is a 16-word by 8-bit static random access memory with synchronous write capability. When the write enable (WE) is Low, transitions on the write clock (WCLK) are ignored and data stored in the RAM is not affected. When WE is High, any positive transition on WCLK loads the data on data inputs (D7 - D0) into the word selected by the 4-bit address (A3 - A0). For predictable performance, address and data inputs must be stable before a Low-to-High WCLK transition. This RAM block assumes an active-High WCLK. However, WCLK can be active-High or active-Low. Any inverter placed on the WCLK input net is absorbed into the block.

The signal output on the data output pin (O7 - O0) is the data that is stored in the RAM at the location defined by the values on the address pins.

The initial contents of RAM16X8S 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)	WCLK	D7-D0	O7-O0
0 (read)	X	X	Data
1 (read)	0	X	Data
1 (read)	1	X	Data
1 (write)		D7-D0	D7-D0
1 (read)		X	Data
Data = word addressed by bits A3 - A0

Figure 9.5 RAM16X8S Implementation XC4000E, XC4000X, Spartan, SpartanXL