A manual for Sound Design Technology's "DSP Programmer" programming box has the following statement:
Hearing aids based on the Sound Design Technologies Wolverine platform can be programmed from a PC and fitting software using an I2C compatible programming interface box. The Wolverine platform natively supports standard I2C communication across the PC interface (PCIF) with 7-bit addressing and the 400 kHz fast mode communication rate. PCIF also maintains communication with the SDA protocol.
A related document, "Application resource Kit (ARK) User's guide" from ON Semiconductors has the following statement.
When this option is selected, the software determines if the selected programming box and connected device support I2C communication. If the software determines that the I2C protocol is supported, the software sends commands to the connected device using the I2C protocol. If the software determines that either the selected programming box or the connected device do not support the I2C protocol, the software sends commands to the device using the SDA protocol.
I am using Sound Design Technology's DSP Programmer v3.0 programming box and the ARK software to communicate with a DSP chip (R3910). The chip has SDA and SCL pins for programming (firmware update, parameters update). When I update some parameters for the chip from the ARK software user interface, I can see a stream of bits transmitting in the SDA pin on an oscilloscope, but the SCL pins stays high. I was assuming the ARK software on PC and the programming box were using the I2C protocol to communicate with the chip, but since the SCL pin did not change at all I am not sure what is going on.
What is the SDA protocol? Searching google is only giving me descriptions of the I2C protocol, as almost all of them contain the text SDA. Searching for something like "difference between SDA and I2C protocol" gives me the same results. The manuals for ARK and programming box are clearly differentiating between I2C and SDA, but I am not sure what keywords I should be searching for on google.
What exactly is the SDA protocol and how is it different from I2C? Also please provide a link to a page or document.