There are several different protocols used for communicating

between devices on a chip, between chips on a PCB$,$ or between different systems. Some are serial and

some are parallel. Included in the communication protocols are SPI, UART, USB, and I$2$C$.$ This problem

will focus on I$2$C$.$ I$2$C is a $2-$wire $($plus ground$)$ open$-$drain protocol where one or more devices are

designated as a Master and the remaining devices are designated as slaves. The $2$ wires connecting the

devices can be referred to as an I$2$C bus. With this protocol, communications ports of the devices are

placed in parallel on the $2-$wire bus. The two nodes in the I$2$C bus are designated as SDA and SCL$.$ In

standard I$2$C protocol there can be up to $128$ slave devices each with unique addresses of

$.$ Assume in a system with a single Master, the following two data sequences

on these two nodes were obtained $($shading has been added to better visualize the relationship between SDA and SCL$)$

where high levels on both nodes are $1\mathrm{.}2$V and low values are $0$V