HC230 datasheet(17/228 Pages) ALTERA

17 / 228 page

Altera Corporation

2–9

September 2008

Preliminary

PLLs and Clock Networks

outputs are cleared on power up. The designer needs to take these into

consideration when designing logic that might evaluate the initial

power-up values of the memory block.

HardCopy II embedded memory consists of M4K and M-RAM memory

blocks and have a one-to-one mapping from Stratix II M4K and M-RAM

resources. Table 2–4 shows the size and features of the different RAM

blocks.

For more information on the Stratix II memory block features, refer to

the Stratix II Device Handbook.

PLLs and Clock

Networks

Both HardCopy II enhanced and fast PLLs are feature rich, supporting

advanced capabilities such as clock switchover, reconfigurable phase

shift, PLL reconfiguration, and reconfigurable bandwidth. PLLs are used

for general-purpose clock management, supporting multiplication,

division, phase shifting, and programmable duty cycle. In addition,

enhanced PLLs support external clock feedback mode, spread-spectrum

clocking, and counter cascading. Fast PLLs offer high speed outputs to

manage the high-speed differential I/O interfaces.

All Stratix II PLL features are supported by HardCopy II PLLs.

Similar to Stratix II FPGAs, HardCopy II devices also support a

power-down mode where unused clock networks can be disabled.

HardCopy II and Stratix II clock control blocks support dynamic

selection of the input clock from up to four possible sources, giving the

designer the flexibility to choose from multiple (up to four) clock sources.

HC230 Datasheet(PDF) 17 Page - Altera Corporation