EP1M350 datasheet(48/86 Pages) ALTERA

48 / 86 page

Altera Corporation

Mercury Programmable Logic Device Family Data Sheet

The Mercury IOE includes programmable delays that can be activated to

ensure zero hold times, minimum clock-to-output times, input IOE

A path in which a pin directly drives a register may require the delay to

ensure zero hold time, whereas a path in which a pin drives a register

through combinatorial logic may not require the delay. Programmable

delays exist for decreasing input pin to core and IOE input register delays.

The Quartus II Compiler can program these delays automatically to

minimize setup time while providing a zero hold time. Delays are also

programmable for increasing the register to pin delays for output and/or

output enable registers. A programmable delay exists for increasing the

tZX delay to the output pin, which is required for ZBT interfaces. Table 10

shows the programmable delays for Mercury devices.

Note to Table 10:

(1)

This delay has four settings: off and three levels of delay.

The IOE registers in Mercury devices share the same source for clear or

preset. Use of the preset/clear is programmable for each individual IOE.

The register(s) can be programmed to power up high or low after

configuration is complete. If programmed to power up low, an

asynchronous clear can control the register(s). If programmed to power

up high, an asynchronous preset can control the register(s). This feature

prevents the inadvertent activation of another device’s active-low input

upon power-up. Figure 26 shows the IOE for Mercury devices.

Table 10. Mercury Programmable Delay Chain

Programmable Delays

Quartus II Logic Option

Input pin to core delay (1)

Decrease input delay to internal cells

Input pin to input register delay

Decrease input delay to input register

Output propagation delay

Increase delay to output pin

Output enable register tCO delay

Increase delay to OE pin

Output tZX delay

Increase tZX delay to output pin

EP1M350 Datasheet(PDF) 48 Page - Altera Corporation