ACEX 1K Programmable Logic Device Family Data Sheet
For designs that require both a multiplied and non-multiplied clock, the
clock trace on the board can be connected to the GCLK1pin. In the Altera
software, the GCLK1pin can feed both the ClockLock and ClockBoost
circuitry in the ACEX 1K device. However, when both circuits are used,
the other clock pin cannot be used.
ClockLock & ClockBoost Timing Parameters
For the ClockLock and ClockBoost circuitry to function properly, the
incoming clock must meet certain requirements. If these specifications are
not met, the circuitry may not lock onto the incoming clock, which
generates an erroneous clock within the device. The clock generated by
the ClockLock and ClockBoost circuitry must also meet certain
specifications. If the incoming clock meets these requirements during
configuration, the ClockLock and ClockBoost circuitry will lock onto the
clock during configuration. The circuit will be ready for use immediately
after configuration. Figure 19 shows the incoming and generated clock
specifications.
13
Figure 19. Specifications for the Incoming & Generated Clocks
Note (1)
+
tI tCLKDEV
tCLK1
tINDUTY
Input
Clock
+
tI tINCLKSTB
tR
tF
tO
tOUTDUTY
ClockLock
Generated
Clock
+
tO
tO tJITTER
tO tJITTER
Note:
(1) The t parameter refers to the nominal input clock period; the t parameter refers to the nominal output clock
I
O
period.
Altera Corporation
37
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