Copyright © 2020
Alazar Technologies Inc.
58
ATS9353 User Manual
No Pre-Trigger (NPT) AutoDMA
Many ultrasonic scanning and medical imaging applications do not need any pre-
trigger data: only post-trigger data is sufficient.
NPT AutoDMA is designed specifically for these applications. By only storing
post-trigger data, the memory bandwidth is optimized.
Figure 8 - AutoDMA NPT Transfers
NPT AutoDMA buffers do not include headers, so it is not possible to get trigger
time-stamps.
More importantly, a BUFFER_OVERFLOW flag is asserted if the on-board memory
overflows, i.e. the amount of memory that has been written into but not not
read out to PCIe bus exceeds the on-board memory size.
NPT AutoDMA can easily acquire data to PC host memory at the maximum
sustained transfer rate of the motherboard without causing an overflow.
Continuous AutoDMA
Continuous AutoDMA is also known as the data streaming mode.
In this mode, data starts streaming across the PCI bus as soon as the ATS9353
is armed for acquisition. It is important to note that triggering is disabled in this
mode.