CAEN
Electronic Instrumentation
UM3148
–
DT5730/DT5725 User Manual rev. 2
28
Multi-Event Memory Organization
Each channel of the DT5730/DT5725 features a SRAM memory to store the acquired events. The memory size for the
event storage is 640 kS/ch or 5.12 MS/s, according to the board version (see
Tab. 1.1
), and it can be divided in a
programmable number of buffers, N
b
(N
b
from 1 up to 1024), by register address 0x800C, as described in
Tab. 9.1
below.
Register Value
Buffer Number
(N
b
)
Size of one Buffer (Samples)
SRAM 640 kS/ch
⁽*⁾
SRAM 5.12 MS/ch
⁽*⁾
0x00
1
640k - 10
5.12M - 10
0x01
2
320k - 10
2.56M - 10
0x02
4
160k - 10
1.28M - 10
0x03
8
80k - 10
640k - 10
0x04
16
40k - 10
320k - 10
0x05
32
20k - 10
160k - 10
0x06
64
10k - 10
80k - 10
0x07
128
5k - 10
40k - 10
0x08
256
2560 - 10
20k - 10
0x09
512
1280 - 10
10k - 10
0x0A
1024
640 - 10
5120 - 10
Tab. 9.1:
Buffer Organization
Having 640 kS memory size as reference, this means that each buffer contains 640k/N
b
samples (e.g. N
b
= 1024 means
640 samples in each buffer).
⁽*⁾IMPORTANT:
For AMC FPGA firmware release <
0.2
, the Size of one Buffer related to each Buffer Number must be
intended as the number of the samples in
Tab. 9.1
. without decreasing by 10 samples.
Custom Sized Events
In case an event size minor than the buffer size is needed, the user can set the value N
LOC
at register address 0x8020;
the event is so forced to be made by 10*N
LOC
samples. Setting N
LOC
= 0, the custom size is disabled. The value of N
LOC
must be set in order that the relevant number of samples does not exceed the buffer size and
it mustn’t be modified
while the acquisition is running.
Note:
Even using the custom size setting, the number of buffers and the buffer size are not affected by N
LOC
, but they
are still determined by N
b
.
The concepts of buffer organization and custom size directly affect the width of the acquisition window (i.e.
number of the digitized waveform samples per event). The
Record Length
parameter defined in CAEN
software (such as WaveDump and CAENScope introduced in §
11
) and the
Set/GetRecordLength()
function
of the CAENDigitizer library (refer to
[RD5]
) rely on these concepts.