62 lines
1.6 KiB
ReStructuredText
62 lines
1.6 KiB
ReStructuredText
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.. -*- coding: utf-8; mode: rst -*-
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.. _FE_SET_VOLTAGE:
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********************
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ioctl FE_SET_VOLTAGE
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********************
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Name
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====
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FE_SET_VOLTAGE - Allow setting the DC level sent to the antenna subsystem.
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Synopsis
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========
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.. c:function:: int ioctl( int fd, FE_SET_VOLTAGE, enum fe_sec_voltage *voltage )
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:name: FE_SET_VOLTAGE
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Arguments
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=========
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``fd``
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File descriptor returned by :ref:`open() <frontend_f_open>`.
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``voltage``
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pointer to enum :c:type:`fe_sec_voltage`
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Valid values are described at enum
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:c:type:`fe_sec_voltage`.
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Description
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===========
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This ioctl allows to set the DC voltage level sent through the antenna
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cable to 13V, 18V or off.
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Usually, a satellite antenna subsystems require that the digital TV
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device to send a DC voltage to feed power to the LNBf. Depending on the
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LNBf type, the polarization or the intermediate frequency (IF) of the
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LNBf can controlled by the voltage level. Other devices (for example,
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the ones that implement DISEqC and multipoint LNBf's don't need to
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control the voltage level, provided that either 13V or 18V is sent to
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power up the LNBf.
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.. attention:: if more than one device is connected to the same antenna,
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setting a voltage level may interfere on other devices, as they may lose
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the capability of setting polarization or IF. So, on those cases, setting
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the voltage to SEC_VOLTAGE_OFF while the device is not is used is
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recommended.
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Return Value
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============
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On success 0 is returned, on error -1 and the ``errno`` variable is set
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appropriately. The generic error codes are described at the
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:ref:`Generic Error Codes <gen-errors>` chapter.
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