Caen N6724, User Manual

Page: 26 / 61

Multi-Event Memory Organization
Each channel of the N6724 features a SRAM memory to store the acquired events. The memory size for
the event storage is 512 kS/ch or 4 MS/ch, 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 the register address 0x800C
[RD1] , as described in Tab. 7.1 .
Register Value Number of Buffers Size of one Buffer
( N
b
) SRAM 1 MB/ch (512 kS) SRAM 8 MB/ch (4 MS)
0x00 1 1 MB/ch (512 kS) 8 MB/ch (4 MS)
0x01 2 512 kB/ch (256 kS) 4 MB/ch (2 MS)
0x02 4 256 kB/ch (128 kS) 2 MB (1 MS)
0x03 8 128 kB/ch (64 kS) 1 MB/ch (512 kS)
0x04 16 64 kB/ch (32 kS) 512 kB/ch (256 kS)
0x05 32 32 kB/ch (16 kS) 256 kB/ch (128 kS)
0x06 64 16 kB/ch (8 kS) 128 kB/ch (64 kS)
0x07 128 8 kB/ch (4 kS) 64 kB/ch (32 kS)
0x08 256 4 kB/ch (2 kS) 32 kB/ch (16 kS)
0x09 512 2 kB/ch (1 kS) 16 kB/ch (8 kS)
0x0A 1024 1 kB/ch (512 S) 8 kB/ch (4 kS)
Tab. 7.1: Buffer organiza on of 724 family series. For each value of buffer size it is reported the memory size and the
number of samples of one buffer, where k = 1024 and M = 1024
·
1024.
Having 512 kS memory size as reference, this means that each buffer contains 512k /
N
b
samples (e.g. N
b
=
1024 means 512 samples in each buffer).
Custom size events
In case an event size less than the buffer size is needed, the user can set the N_LOC value at register address
0x8020
[RD1] , where N_LOC is the number of memory loca ons. The size of the event is so forced to be
according to the formula:
1
∗
N_LOC = 2
∗
N
Sample
When N_LOC = 0 the custom size is disabled.
Note : The value of N_LOC must be set in order that the relevant number of samples does not exceed the
buffer size and it must not be modified while the acquisi on is running. Even using the custom size se ng,
the number of buffers and the buffer size are not affected by N_LOC, but they are s ll determined by N
b
.
The concepts of buffer organiza on and custom size directly affect the width of the acquisi on window (i.e.
number of the digi zed waveform samples per event). The Record Length parameter defined in CAEN so -
ware (such as WaveDump and CAENScope introduced in Chap.
So ware Tools ) and the Set/GetRecordLength()
func ons of the CAENDigi zer library (see Sec. Libraries ) rely on these concepts.
26 UM3247 - N6724 User Manual rev. 10