Programmability Options (cont.)
Static Random Access Memory (SRAM) Programming:
- Configuration bits are stored in SRAM. Can be reprogrammed infinite number of times.
- Programming contents NOT retained after power down; FPGA must be 'configured' everytime on power up.
- External non-volatile memory device required to hold device programming; on power up contents of external device transferred to FPGA to configure the device.
- Altera, Xilinx corporations offer this type of FPGAs.
Highest density FPGAs use SRAM for configuration bits.