Agilent Technologies VXI E1439 - Manual (Page 123)

113
Agilent E1439 Programmer's Reference
Functions listed alphabetically
AGE1439_BOF_OFF is the default setting. It blocks the transmission of all automatically
generated BOF events. However, programmatically generated BOF events such as age1439_
fiber_xmt_BOF ,whichareusedinthesynchronizationoffiberinterfaces,arenotblocked.
bofEnablePtr points to the current value of bofEnable.
crcEnable determines whether or not cyclic redundancy checking (CRC) is performed on the fiber receiver
and whether or not that information will be transmitted. Generally, cyclic redundancy checking
should be enabled, but turning CRC off may solve compatibility problems with some fiber optic
receivers.
AGE1439_CRC_ON enables CRC checking.
AGE1439_CRC_OFF disables CRC checking.
crcEnablePtr points to the current value of crcEnable.
fiberMode is used to turn the fiber interface off, configure it to copy data from the receiver to the transmitter
port without adding data, configure the transmission of filtered ADC data, or configure appending
ADC data to received data.
AGE1439_FIBER_MODE_RAW allows the transmission of unfiltered full bandwidth ADC data
at the same time filtered ADC data is available to read on the VME bus or the local bus.
AGE1439_FIBER_MODE_OFF turns off both the fiber transmitter and receiver (although PIO1,
PIO2, NRDY and DIR bits are still received). Normal data collection and digital processing
continues.
Note
If age1439_data_port is set to fiber while the fiber interface is turned off, the data FIFO will fill
up with filtered ADC data and collection will stop. In this case,
age1439_meas_status_get will
return the error, AGE1439_NO_DATA_MEASUREMENT_PAUSED .
AGE1439_FIBER_MODE_COPY is the default fiberMode at power-on and reset. Data is copied
from the fiber interface receiver to the fiber interface transmitter while the module is performing
other measurements. For instance, filtered ADC data can be sent on the LBUS or read from the
FIFO over the VME bus in accordance with the current setting of the age1439_data_port
function, with this parameter set. However, selecting fiber as the data port while using this mode
will result in setting the
AGE1439_STATUS_SETUP_ERROR bit in the status register. This
occurs because the fiber interface cannot perform both functions at the same time.
Note
The E1439D fiber receiver’s detect signal is used to activate the fiber transmitter. The E1439D
fiber interface is not a data receiver. The function of the receive port is limited to copying data to
the transmit port and to detecting FPDP control signals (e.g., PIO bits and flow control signals).
Since signal detect works on light energy alone, there does not need to be valid data on the fiber
receiver for there to be an output from the transmitter. If there is valid data present on the fiber
receiver, it is copied to the fiber transmitter. This preserves data transparency but not necessarily
protocol transparency. The outgoing protocol is always serial FPDP.
AGE1439_FIBER_MODE_RAW transmits unprocessed and unbuffered ADC data over the fiber
interface. After selection, optical data transmission begins when the first measurement is
triggered, and continues indefinitely after the measurement is complete. Transmission will
continue until the fiber mode is changed to something other than
AGE1439_FIBER_MODE_
RAW or a fiber error occurs. While this raw data is being transmitted, filtered ADC data can still
be sent over the local bus, or read from the FIFO via the VME bus. Attempting to set AGE1439_