Spartan6　FPGA中的块存储器使用指南，可以构建为FIFO，ROM，RAM，移位寄存器等。-Spartan6 FPGA block memory in the User Guide, you can build for FIFO, ROM, RAM, shift registers and so on.

The Virtex™ series provides dedicated blocks of on-chip, true dual-read/write port synchronous RAM, with 4096 memory cells. Each port of the block SelectRAM+™ memory can be independently configured as a read/write port, a read port, o