Specifications

40 Altera Corporation
EPXA10 Development Board Hardware Reference Manual
Sources for the Stripe Clock Reference
There are three options for providing a source for the stripe clock
reference:
■ External clock generator
■ Main clock
■ An alternative crystal oscillator
Methods of selecting these options are given below.
Using an External Clock Generator
To select an external clock generator, use the following jumper settings:
■ Set JP51 to position 1-2 to disable the main clock X7
■ Set JP33 to terminate the clock generator at 50Ω
Using the Main Clock
To use the main clock, set JP51 to position 2-3 to enable the crystal
oscillator.
Using a Variable Oscillator
To use a variable oscillator as the stripe clock reference, follow the steps
below:
1. Plug in the DIL14 crystal oscillator package.
2. Disable the main clock, X7, by connecting pins 1 and 2 at JP51.
3. Provide a 5-V power supply on the board, either by connecting the
ATX power supply or by connecting an alternative 5-V input to JP35.
 The clock buffer converts 5-V input from the crystal oscillator to
the 3.3 V required for the stripe.