FLEX 10K Embedded Programmable Logic Device Family Data Sheet
Figure 17. Enabling ClockLock & ClockBoost in the Same Design
CLOCKBOOST=1
INPUT_FREQUENCY=50
CLKLOCK
aout
a
D
Q
gclk1
CLOCKBOOST=2
INPUT_FREQUENCY=50
CLKLOCK
bout
b
D
Q
To use both the ClockLock and ClockBoost circuits in the same design,
designers must use Revision C EPF10K100GC503-3DX devices and
MAX+PLUS II software versions 7.2 or higher. The die revision is
indicated by the third digit of the nine-digit code on the top side of the
device.
This section discusses the peripheral component interconnect (PCI)
pull-up clamping diode option, slew-rate control, open-drain output
option, MultiVolt I/O interface, and power sequencing for FLEX 10K
devices. The PCI pull-up clamping diode, slew-rate control, and
open-drain output options are controlled pin-by-pin via Altera logic
options. The MultiVolt I/O interface is controlled by connecting VCCIO to
a different voltage than VCCINT. Its effect can be simulated in the Altera
software via the Global Project Device Options dialog box (Assign
menu).
Output
Configuration
PCI Clamping Diodes
The EPF10K10A and EPF10K30A devices have a pull-up clamping diode
on every I/O, dedicated input, and dedicated clock pin. PCI clamping
diodes clamp the transient overshoot caused by reflected waves to the
VCCIO value and are required for 3.3-V PCI compliance. Clamping diodes
can also be used to limit overshoot in other systems.
Clamping diodes are controlled on a pin-by-pin basis via a logic option in
the Altera software. When VCCIO is 3.3 V, a pin that has the clamping
diode turned on can be driven by a 2.5-V or 3.3-V signal, but not a 5.0-V
signal. When VCCIO is 2.5 V, a pin that has the clamping diode turned on
can be driven by a 2.5-V signal, but not a 3.3-V or 5.0-V signal. However,
a clamping diode can be turned on for a subset of pins, which allows
devices to bridge between a 3.3-V PCI bus and a 5.0-V device.
38
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