Q: I recently came across two of your products – the Cheetah SPI Host Adapter and the Aardvark I2C/SPI Host Adapter. I am interested in programming SPI data, but I'm not sure which SPI host adapter I should use. Can either of these host adapters support 16-bit, 32-bit, or larger continuous transfers to an SPI slave? I'm looking to generate up to a 128-bit stream with no delays between bytes.

A: Thanks for your question! To answer your question about the data transfers, we'll first give a little background about the Cheetah and Aardvark adapters.

• The Aardvark I2C/SPI Host Adapter is an active programming tool with master and slave capabilities. As an SPI master, the Aardvark operates at up to 8 MHz; as an SPI slave, the Aardvark functions at up to 4 MHz.

The Aardvark adapter in use as an SPI slave with the Control Center Software.

• The Cheetah SPI Host Adapter is a high-speed SPI master capable of communication over SPI at up to 40+ MHz.

Cheetah SPI Host Adapter

The Cheetah SPI Host Adapter can send 16-bit, 32-bit, and 128-bit transfers without any delay between the bytes. Moreover, the Cheetah adapter can send an arbitrary number of bytes without a delay between bytes.  The Aardvark I2C/SPI Host Adapter has similar functionality at a slower speed, but also inserts a small delay between each byte. For your project, the Cheetah adapter appears to be the best tool to use for programming continuous data transfers.

Check out the datasheets for the Cheetah and Aardvark adapters to learn more about the SPI signaling characteristics.

Cheetah SPI Host Adapter – SPI Signaling Characteristics

Aardvark I2C/SPI Host Adapter – SPI Signaling Characteristics

Additionally, if you are interested in primarily monitoring and analyzing SPI data, Total Phase offers the Beagle I2C/SPI Protocol Analyzer. The Beagle I2C/SPI analyzer non-intrusively monitors the SPI bus at up to 24 MHz and provides bit-level timing down to a 20 ns resolution. This SPI bus analyzer provides real-time capture and display of data on the SPI bus, allowing engineers to interactively filter and analyze data transactions.

The Beagle I2C/SPI analyzer monitoring an SPI bus with the Data Center Software.

We hope this answers your question! If you have any more questions, feel free to contact us at sales@totalphase.com or support@totalphase.com.