DOC E10523 Rev.D
Interactive Circuits And Systems Ltd. 2000
36
5.9 Buffer Length Register
Read/Write
The Buffer Length register is used to determine the number of samples stored in the
ICS-130 Swing Buffer. The register must be programmed with the number of 32-bit words
(i.e. pairs of samples) to be acquired in the buffer prior to each interrupt or to completion. In
continuous mode, the 19-bit buffer length value determines the number of 32-bit words
written to the swing buffer by the ADCs before the buffer banks are swapped. In Capture
mode, the value programmed determines the total number of sample pairs acquired for all
active channels before acquisition terminates. When operating in Capture mode without
pre-trigger storage, the buffer length selected must be an integral multiple of the Acquisition
Count. The value must be written to this register as one less than the required buffer length.
If the ADC interrupt is enabled, a VMEbus interrupt will occur when the programmed length
is reached. The valid range of numbers that may be programmed to this register is 0 to
524287. The maximum value is equivalent to the maximum swing buffer capacity of
1Msample (each side).
The user must perform an ADC Reset (by writing to the ADC Reset register) after loading
the Buffer Length, Acquisition Count, Decimation and Frame Count registers in order for the
new values to take effect.
5.10 Acquisition Count Register
Read/Write
The Acquisition Count register determines the number of acquisition frames (a frame
contains one sample for each channel currently active) stored in the swing buffer following
each application of a trigger, when operating in Capture mode with no pre-trigger storage.
When operating in Capture mode with pre-trigger storage, it determines the number of
frames acquired after the (single) occurrence of the trigger. The valid range of numbers that
may be programmed to this register is 1 to 524287.
The user must perform an ADC Reset (by writing to the ADC Reset register) after loading
the Buffer Length, Acquisition Count, Decimation and Frame Count registers in order for the
new values to take effect.
