Commit 26b9c12e authored by Jonas Künzli's avatar Jonas Künzli Committed by overleaf
Browse files

Update on Overleaf.

parent d99d3c5e
......@@ -254,9 +254,10 @@ $$U_p+U_s\leq 1$$
U_s &= \frac{C_s}{T_s}
\end{align}
When the $k$-th aperiodic request arrives at time $t=r_k$, it receives a
deadline $$d_k=\max\{r_k,d_{k-1}\}+\frac{C_k}{U_s}$$ where $C_k$ is the
When the $k$-th aperiodic request arrives at time $t=r_k$ , it receives a
deadline (Tasks nach arrival times ordnen und deadlines berechnen) $$d_k=\max\{r_k,d_{k-1}\}+\frac{C_k}{U_s}$$ where $C_k$ is the
execution time of the request and $U_s $ the server utilization factor
(=bandwidth). $U_S$ can be chosen such that $U_s\leq 1-U_p$ (necessary and
sufficient).
sufficient).\newline
The worst case finishing time of an aperiodic task is the calculated deadline.
......@@ -86,15 +86,28 @@ ES are expected to finish tasks reliably within time bounds.\\ Essential: Upper
\end{compactitem}
\includegraphics[width=0.6\linewidth]{symbols_cyclic_exec_scheduler}
\textbf{Conditions}:
\begin{compactitem}
\item Process executes at most once within a frame:\\ $\forall$ Tasks $\tau_i$: $f \leq T_i$
\item $P$ is a multiple of $f$
\item Period $P$ is least common multiple of all periods $T_i$
\item Processes start and complete within a single frame: $\forall$ Tasks $\tau_i$: $f \geq C_i$
\item Between release time and deadline of a task, there is at least one frame boundary: $\forall$ Tasks $\tau_i$: $2f-\text{gcd}(T_i,f) \leq D_i$
\end{compactitem}
~\newline
\textbf{Conditions}: \\
\begin{tabularx}{\columnwidth}{|X|X|}
\hline
Process executes at most once within a frame: & $f\leq T_i \quad \forall i$ \\
\hline
$P$ is a multiple of $f$ & $\exists i: T_i \mod f = 0$ \\
\hline
Processes start and complete within a single frame: & $f\geq C_i \quad \forall i$ \\
\hline
Between release time and deadline of a task, there is at least one frame boundary: & $2f-\gcd (T_i,f)\leq D_i \quad \forall i$ \\
\hline
\end{tabularx}
Period $P$ is least common multiple of all periods $T_i$.\\
%\begin{compactitem}
%\item Process executes at most once within a frame:\\ $\forall$ Tasks $\tau_i$: $f \leq T_i$
%\item $P$ is a multiple of $f$
%\item Period $P$ is least common multiple of all periods $T_i$
%\item Processes start and complete within a single frame: $\forall$ Tasks $\tau_i$: $f \geq C_i$
%\item Between release time and deadline of a task, there is at least one frame boundary: $\forall$ %Tasks $\tau_i$: $2f-\text{gcd}(T_i,f) \leq D_i$
%\end{compactitem}
%~\newline
\textbf{Check for correctness} of schedule: 4-32\\
\begin{itemize}
......
......@@ -80,6 +80,7 @@ A low priority task holds a Semaphore and prevents a high priority task from run
\textbf{Problems:}
\begin{itemize}
\item Deadlocks: can be solved with Watchdog timers
\includegraphics[width=0.5\linewidth]{images/deadlock.JPG}
\end{itemize}
......
......@@ -34,7 +34,7 @@ Main sources:
$f$ : & \quad Clock Frequency \\
$V_T$ : & \quad Threshold Voltage $V_T \ll V_{dd}$
\end{tabularx}
~\newline
$P\propto V_{dd}^2$ and $f\propto V_{dd}^2$ so $P\propto V_{dd}^3$ \\
\ownsubsection{Basic Techniques (9-16)}
\textbf{Power Supply Gating}: Cut off power supply to inactive units to reduce leakage
......
......@@ -44,9 +44,9 @@ $\to$ The main difference between general purpose processors and embedded system
\end{compactitem}
\ownsubsection{FPGA, Application Specific Circuits (ASICS) and SoC}
$\to$ On every characteristic of an FPGA you loose a factor 10 vs ASIC.
\textbf{ASIC}: If ultimate speed and energy efficiency are necessary and large numbers can be sold or there is a lot of money (military)
$\to$ On every characteristic of an FPGA you loose a factor 10 vs ASIC.\\
\textbf{FPGA}:more flexible (reprogrammable)\\
\textbf{ASIC}: have a fixed application (not flexible),are harder to design,expensive, have a better fitting for specific application.\\If ultimate speed and energy efficiency are necessary and large numbers can be sold or there is a lot of money (military)
\textbf{Trends}:
\begin{compactitem}
......
......@@ -5,7 +5,7 @@
\pagestyle{fancy}
\lhead{Embedded Systems}
\chead{FS19}
\rhead{Very Cool Kids}
\rhead{Very Cool Embedded System Kids}
\begin{document}
\begin{multicols*}{3}
......
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