Q$4.$

$($a$)$ Serial Peripheral Interface Bus $($SPI$)$ is a serial data protocol which operates with a master$/$slave relationship over a short distance. In an embedded system, it allows microcontrollers or their equivalent to communicate with peripherals in a serial mode.

$($i$)$ For a system using an SPI bus, list the signals which are required for bus control and sketch a layout with three slave devices. You can choose either a three or four wire configuration.

$(10$ marks$)$

$($ii$)\backslash (\backslash$quad $\backslash$mathrm$\{$I$\}^\{2\}\backslash$mathrm$\{$C$\}\backslash )$ protocol can also be used for serial data transmission and is often used instead of SPI. Compare the two protocols, highlighting the advantages and disadvantages of each.

$(8$ marks$)$

$($b$)$ An $8051$ microcontroller has XTAL of $11\mathrm{.}0592$ MHz $.$ Find the TH$1$ value $($in both decimal and hexadecimal$)$ to set the required baud rate by using following conditions:

$($i$)14400$ if $\backslash ($ S M O D$=0\backslash )$

$(3$ marks$)$

$($ii$)2400$ if $\backslash (\backslash$mathrm$\{$SMOD$\}=1\backslash )$