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AsteRx-m2a OEM
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2.6
External Frequency Reference Input (REF IN)
An external 10 MHz frequency reference can be fed into the receiver through pin#60 of
the 60-pin connector (REF IN). The 10 MHz signal can be a sine wave or a square wave
with a peak-to-peak amplitude between 2V and 5V, for example it can be an LVTTL clock
signal.
At start-up, the AsteRx-m2a checks the presence of the external frequency reference on
pin#60. If a signal is present, the receiver uses that signal as primary frequency reference,
instead of its internal TCXO. The reference signal must be present on pin#60 at receiver
boot and must remain present at all times during receiver operation.
This feature is under permission. Make sure that the FreqSync permission is enabled if
you need to use the REF IN pin. If the receiver detects a 10 MHz signal on its REF IN pin
and the FreqSync permission is disabled, most output will be blocked.
2.7
Event Inputs
The receiver features two event inputs (EventA on the 30-pin connector, and EventB on
the 60-pin connector), which can be used to time tag external events. Use the
setEventParameters
command to configure these pins (e.g. to set the polarity). Note
that this feature requires the TimedEvent permission to be enabled in the receiver.
2.8
General Purpose Output (GPx)
The GP1 and GP2 pins of the 60-pin connector are general purpose LVTTL digital outputs,
of which the level can be programmed with the
setGPIOFunctionality
command.
During the first seconds after powering up the board, these pins are in tristate. Use an
external pull-down or pull-up resistor to have the desired level during boot.
The GPx pins can drive a maximum current of 10mA.
2.9
Standby Mode
In standby mode, all receiver functions are turned off and the power consumption is very
low (see section 2.3). There are two ways to enter standby mode:
1.
By driving the nPDN pin low (pin#20 of the 30-pin connector). The receiver wakes
up when the nPDN pin level is high again (there is an internal pull-up).
2.
By entering the “
exePowerMode, StandBy
”
user command. To wake up, the nPDN
pin should be shortly driven low (at least for 50ms).
