PulseBlasterESR-PRO
Clock Oscillator Header
The PulseBlasterESR-PRO comes with a crystal oscillator mounted on the oscillator socket to
provide a timing signal for the board. If required, it is possible to remove the oscillator that comes
standard, and instead drive the PulseBlasterESR-PRO with an external clock signal. The oscillator
module can be removed from the board, and an external signal can be input through the header pins. Do
not attempt to drive a PulseBlaster board with an external clock while an oscillator module is also
connected. The standard clock oscillator’s orientation should be noted - if the clock oscillator is
reconnected, it must be inserted in the same orientation or board damage may occur. The external clock
signal must be a TTL square wave, i.e. a digital signal of no more than 3.3 V. This is the absolute
maximum allowable voltage, typically a voltage of 1.5-2 V is sufficient. Be aware that the TTL signal must
be a positive-only signal, any negative voltage will damage the programmable-logic chip.
Please take caution to provide a controlled signal at the correct frequency. The PulseBlasterESR-
PRO requires a 50 MHz signal. A reliable option for this purpose is the
Oven Controlled Clock Oscillator
available for purchase. This component will provide a precision low ripple signal for all PulseBlaster
boards, and ensure that appropriate signal voltages are applied to the board. Information on this product
can be found in the “Related Products and Accessories” section.
2019/09/26
Figure 14:
PulseBlasterESR-PRO clock header. Both the bare header
socket and the installed clock module are shown above. Please note the
proper orientation of the 50 MHz clock.
