Dual port AutoDMA Sample Clauses

Dual port AutoDMA. ‌ AutoDMA allows a board to capture sample data to on-board dual-port memory while – at the same time – transferring sample data from on-board dual-port memory to a buffer in host memory. Data acquisition and data transfer are done in parallel, so any trigger events that occur while the board is transferring data will not be missed. AutoDMA may be used if: • A board has dual-port or FIFO on-board memory. • An application acquires at an average rate, in MB/s, that is less than maximum transfer rate of your board’s PCI or PCIe host bus interface. AutoDMA must be used if: • A board has FIFO on-board memory. • An application cannot miss trigger events that occur while it transfers data to host memory, or re-arms for another acquisition. • An application acquires more sample points or records than can be stored in on-board memory. Applications such as ultrasonic testing, OCT, radar, and imaging should use AutoDMA. An AutoDMA acquisition is divided into segments. AutoDMA hardware on a board transfers sample data, one segment at a time, from on-board memory to a buffer in host memory. There may be an unlimited number of segments in an AutoDMA acquisition, so a board can be armed to make an acquisition of infinite duration. There are four AutoDMA operating modes. AutoDMA mode Triggered Pre- trigger samples Record headers Description Traditional Yes Yes Optional Acquire multiple records – one per trigger event. Each record may contain samples before and after its trigger event. Each buffer contains one or more records. A record header may optionally precede each record. NPT (NoPreTrigger) Yes No No Acquire multiple records – one per trigger event. Each record may contain only samples after its trigger event. Each buffer contains one or more records.