National Instruments PCI-8431/4 Serial Interface

The PCI-8431/4 (Part Number: 778981-01) comes without DMA transfers, so an interrupt is shown by the serial interface every time the FIFO gets a determined level. If the CPU is not capable of processing that interrupt in a matter of time, the instrument will use handshaking (if it is available) to close the data transfer. As a result, the complete throughput is minimized and is typical with smaller FIFOs. The top signal represents the bytes "ABCDEFG" being transferred across the serial interface using DMA. The bottom signal illustrates the results of using switches with a small FIFO. If the CPU receives too much data to transfer to memory, the FIFO fills up and the NI PCI-8431/4 Serial Interface signals the instrument to stop transmitting data while the CPU catches up. As a result, the top signal transfers more data in the same amount of time and therefore has an increase in throughput.

The NI PCI-8431/4 allows the user to simply customize any baud rate between 50 b/s and 2 Mb/s through programming. This is possible through manual configuration by using MAX (Measurement & Automation Explorer) or Windows Device Manager, or the user can programmatically change it through the NI-Serial application programming interface (API).

The NI PCI-8431/4 Serial Interface offers multiprocessor and hyper-threading support, so the user can take advantage of the latest PC technology for higher speeds and better efficiency. Hyper-threading is a technology included in some Intel processors that enables one processor to work as two. To achieve this, the "core" can process two threads of commands at the same time.

PCI-8431/4 Mature Status has been announced by National Instruments, but will still be available for purchase and repairs by Apex Waves.