Figure 1: Promira Serial Platform

The Promira Serial Platform supports the I2C master mode at 1 kHz to 1.02 MHz, and the I2C slave mode at 1 kHz to 500 kHz; offering programming speeds up to 2x faster than that of the Aardvark adapter. When using USB 2.0 connectivity, the Promira platform uses a high-speed USB link between the Promira platform and the computer, which reduces the USB latency from 2ms to about 250us. The Promira platform also has an asynchronous interface that may provide additional speed-up for your setup. Other advanced features include functioning as an I2C master up to 1 MHz, Integrated level shifting from 0.9V to 5.0V, and USB 2.0 / Ethernet connectivity for faster downloads, remote control, and factory floor automation.

Regarding delays, every Promira platform I2C master read transaction will have a delay before the last byte, and there may be additional delays between bytes during the I2C master read and write. Although there is no inter-byte delay for the most part of the I2C transaction, the Promira Serial Platform occasionally requires additional time to process the received bytes and set up the next bytes. In this case, delay is inserted on the I2C bus. There can also be additional overhead caused by the operating system between the Promira API calls. For more information about the Promira I2C signaling characteristics, please refer to section 2.2 of the Promira Serial platform User Manual. For more information about Promira Software API, please refer to section 5 of the Promira Serial Platform User Manual.

There are delays that are inherent to the I2C bus protocol. The I2C requires that 9 bits are sent for every 8 bits of data; the throughput will not be exactly 1/8 times the bitrate. The maximum bitrates are only achievable within each individual byte; the bitrates do not extend across bytes. There is also a finite time required to set up a byte transmission.