Subversion Repositories openarty

\documentclass{gqtekspec}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%

%% Filename:    spec.tex

%%

%% Project:     OpenArty, an entirely open SoC based upon the Arty platform

%%

%% Purpose:

%%

%% Creator:     Dan Gisselquist, Ph.D.

%%              Gisselquist Technology, LLC

%%

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%

%% Copyright (C) 2015-2016, Gisselquist Technology, LLC

%%

%% This program is free software (firmware): you can redistribute it and/or

%% modify it under the terms of  the GNU General Public License as published

%% by the Free Software Foundation, either version 3 of the License, or (at

%% your option) any later version.

%%

%% This program is distributed in the hope that it will be useful, but WITHOUT

%% ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY or

%% FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

%% for more details.

%%

%% You should have received a copy of the GNU General Public License along

%% with this program.  (It's in the $(ROOT)/doc directory, run make with no

%% target there if the PDF file isn't present.)  If not, see

%% <http://www.gnu.org/licenses/> for a copy.

%%

%% License:     GPL, v3, as defined and found on www.gnu.org,

%%              http://www.gnu.org/licenses/gpl.html

%%

%%

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%

%%

\usepackage{import}

\usepackage{bytefield}

\project{OpenArty}

\title{Specification}

\author{Dan Gisselquist, Ph.D.}

\email{dgisselq (at) opencores.org}

\revision{Rev.~0.0}

\begin{document}

\pagestyle{gqtekspecplain}

\titlepage

\begin{license}

Copyright (C) \theyear\today, Gisselquist Technology, LLC

This project is free software (firmware): you can redistribute it and/or

modify it under the terms of  the GNU General Public License as published

by the Free Software Foundation, either version 3 of the License, or (at

your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT

ANY WARRANTY; without even the implied warranty of MERCHANTIBILITY or

FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

for more details.

You should have received a copy of the GNU General Public License along

with this program.  If not, see \texttt{http://www.gnu.org/licenses/} for a copy.

\end{license}

\begin{revisionhistory}

0.0 & 6/20/2016 & Gisselquist & First Draft \\\hline

\end{revisionhistory}

% Revision History

% Table of Contents, named Contents

\tableofcontents

\listoffigures

\listoftables

\begin{preface}

\end{preface}

\chapter{Introduction}

\pagenumbering{arabic}

\setcounter{page}{1}

% What is old

%       Arty, XuLA

% What does the old lack?

%       Arty lacks open interfaces, instead using MIG and CoreGen w/ AXI bus

% What is new

%       OpenArty has its own memory interface controller, and runs everything

%       off of an open Wishbone bus structure.

% What does the new have that the old lacks

%

% What performance gain can be expected?

%

The goals of this project include:

\begin{enumerate}

\item Use entirely open interfaces

        This means not using the Memory Interface Generator (MIG), the

        Xilinx CoreGen IP, etc.  Further, I wish to use all of Arty's on--board

        hardware: Flash, DDR3-SDRAM, Ethernet, and everything else at their

        full and fastest speed(s).  For example, the flash will need to be

        clocked at 100~MHz, not the 50~MHz I've clocked it at before.  The

        memory should also be able to support pipelined 32--bit interactions

        over the Wishbone bus at a 200~MHz clock.  Finally, the Ethernet

        controller should be supported by a DMA capable interface that can

        drive the ethernet at its full 100Mbps rate.

\item Run using a 200~MHz clock, if for no other reason than to gain the

        experience of building logic that can run that fast.

\item Modify the ZipCPU to support an MMU and a data cache, and perhaps even

        a floating point unit.

\item The default configuration will also include three Pmods: a USBUART,

        an SDCard, and the GPS Pmod.

\end{enumerate}

I intend to demonstrate this project with a couple programs:

\begin{enumerate}

\item A very simple program that runs automatically upon startup that can be

        used to select from among multiple configurations.

\item NTP Server

\item A ZipOS that can actually load and run programs from the SD Card

\end{enumerate}

\chapter{Architecture}

\chapter{Software}

\section{Directory Structure}

\section{Zip CPU Tool Chain}

\section{Bench Test Software}

\section{Host Software}

\begin{itemize}

\item {\tt readflash}: As I am loathe to remove anything from

        a device that came factory installed, the

        {\tt readflash} program reads the original installed

        configuration from the flash and dumps it to a file.

\item {\tt wbregs}: This program offers a capability very similar to the

        PEEK and POKE capability Apple user's may remember from before the

        days of Macintosh.  {\tt wbregs <address>} will read from the

        Wishbone bus the value at the given address.  Likewise

        {\tt wbregs <address> <value>} will write the given value into the

        given address.  While both address and value have the semantics of

        numbers acceptable to {\tt strtoul()}, the address can also be a named

        address.  Supported names can be found in {\tt regdefs.cpp}, and their

        register mapping in {\tt regdefs.h}.

\item {\tt ziprun}:

\item {\tt zipload}:

\end{itemize}

\section{Zip CPU Programs}

\begin{itemize}

\item {\tt ntpserver}:

\item {\tt goldenstart}:

\end{itemize}

\section{ZipOS}

\subsection{System Calls}

\begin{itemize}

\item {\tt int wait(unsigned event\_mask, int timeout)}

\item {\tt int clear(unsigned event\_mask, int timeout)}

\item {\tt void post(unsigned event\_mask)}

\item {\tt void yield(void) }

\item {\tt int read(int fid, void *buf, int len)}

\item {\tt int write(int fid, void *buf, int len)}

\item {\tt unsigned time(void) }

% \item SEMGET

% \item SEMPUT

\item {\tt void *malloc(void)}

\item {\tt void free(void *buf)}

% \item FORK

% \item opendir

% \item EXEC

% \item OPEN

\end{itemize}

\subsection{Scheduler}

\chapter{Operation}

\chapter{Registers}

There are several address regions on the S6~SoC, as shown in

Tbl.~\ref{tbl:memregions}.

\begin{table}[htbp]

\begin{center}\begin{tabular}{|p{2.25in}|p{0.6in}|p{0.45in}|p{2.0in}|}\hline

\rowcolor[gray]{0.85} Binary Address & Base & Size(W) & Purpose \\\hline\hline

\scalebox{0.9}{\tt 0000 0000 0000 0000 0001 000x xxxx} & \scalebox{0.9}{\tt 0x00000100} & \hfill 32 & Peripheral I/O Control \\\hline

\scalebox{0.9}{\tt 0000 0000 0000 0000 0001 0010 0yyx} & \scalebox{0.9}{\tt 0x00000120} & \hfill 8 & Debug scope control\\\hline

\scalebox{0.9}{\tt 0000 0000 0000 0000 0001 0010 10xx} & \scalebox{0.9}{\tt 0x00000128} & \hfill 4 & RTC control\\\hline

\scalebox{0.9}{\tt 0000 0000 0000 0000 0001 0010 11xx} & \scalebox{0.9}{\tt 0x0000012c} & \hfill 4 & SDCard controller\\\hline

\scalebox{0.9}{\tt 0000 0000 0000 0000 0001 0011 00xx} & \scalebox{0.9}{\tt 0x00000130} & \hfill 4 & GPS Clock loop control\\\hline

\scalebox{0.9}{\tt 0000 0000 0000 0000 0001 0011 01xx} & \scalebox{0.9}{\tt 0x00000134} & \hfill 4 & Network packet interface\\\hline

\scalebox{0.9}{\tt 0000 0000 0000 0000 0001 0011 10xx} & \scalebox{0.9}{\tt 0x00000138} & \hfill 4 & OLEDrgb control\\\hline

\scalebox{0.9}{\tt 0000 0000 0000 0000 0001 0011 11xx} & \scalebox{0.9}{\tt 0x0000013c} & \hfill 4 & {\em Unused}\\\hline

\scalebox{0.9}{\tt 0000 0000 0000 0000 0001 0100 0xxx} & \scalebox{0.9}{\tt 0x00000140} & \hfill 8 & GPS Testbench\\\hline

\scalebox{0.9}{\tt 0000 0000 0000 0000 0001 0100 1xxx} & \scalebox{0.9}{\tt 0x00000148} & \hfill  8 & {\em Unused}\\\hline

\scalebox{0.9}{\tt 0000 0000 0000 0000 0001 0101 xxxx} & \scalebox{0.9}{\tt 0x00000150} & \hfill 16 & {\em Unused}\\\hline

\scalebox{0.9}{\tt 0000 0000 0000 0000 0001 011x xxxx} & \scalebox{0.9}{\tt 0x00000160} & \hfill 32 & {\em Unused}\\\hline

\scalebox{0.9}{\tt 0000 0000 0000 0000 0001 100x xxxx} & \scalebox{0.9}{\tt 0x00000180} & \hfill 32 & {\em Unused}\\\hline

\scalebox{0.9}{\tt 0000 0000 0000 0000 0001 101x xxxx} & \scalebox{0.9}{\tt 0x000001a0} & \hfill 32 & Ethernet configuration registers\\\hline

\scalebox{0.9}{\tt 0000 0000 0000 0000 0001 110x xxxx} & \scalebox{0.9}{\tt 0x000001c0} & \hfill 32 & Extended Flash Control Port\\\hline

\scalebox{0.9}{\tt 0000 0000 0000 0000 0001 111x xxxx} & \scalebox{0.9}{\tt 0x000001e0} & \hfill 32 & ICAPE2 Configuration Port\\\hline

\scalebox{0.9}{\tt 0000 0000 0000 0000 10xx xxxx xxxx} & \scalebox{0.9}{\tt 0x00000800} & \hfill 1k & Ethernet TX Buffer\\\hline

\scalebox{0.9}{\tt 0000 0000 0000 0000 11xx xxxx xxxx} & \scalebox{0.9}{\tt 0x00000c00} & \hfill 1k & Ethernet RX Buffer\\\hline

\scalebox{0.9}{\tt 0000 0000 0000 1xxx xxxx xxxx xxxx} & \scalebox{0.9}{\tt 0x00008000} & \hfill 32k & On-chip Block RAM\\\hline

\scalebox{0.9}{\tt 0000 01xx xxxx xxxx xxxx xxxx xxxx} & \scalebox{0.9}{\tt 0x00400000} & \hfill 4M & QuadSPI Flash\\\hline

\scalebox{0.9}{\tt 01xx xxxx xxxx xxxx xxxx xxxx xxxx} & \scalebox{0.9}{\tt 0x04000000} & \hfill 64M & DDR3 SDRAM\\\hline

\scalebox{0.9}{\tt 1000 0000 0000 0000 0000 0000 000x} & \scalebox{0.9}{\tt 0x08000000} & \hfill 2 & ZipCPU debug control port---only visible to debug WB master\\\hline

\end{tabular}

\caption{Address Regions}\label{tbl:memregions}

\end{center}\end{table}

\begin{table}[htbp]

\begin{center}\begin{tabular}{|p{0.9in}|p{0.45in}|p{3.5in}|}\hline

\rowcolor[gray]{0.85} Base & Size(W) & Purpose \\\hline\hline

\scalebox{0.9}{\tt 0x0c0000000} & 1 & Primary Zip PIC\\\hline

\scalebox{0.9}{\tt 0x0c0000001} & 1 & Watchdog Timer\\\hline

\scalebox{0.9}{\tt 0x0c0000002} & 1 & Bus Watchdog Timer\\\hline

\scalebox{0.9}{\tt 0x0c0000003} & 1 & Alternate Zip PIC\\\hline

\scalebox{0.9}{\tt 0x0c0000004} & 1 & ZipTimer-A\\\hline

\scalebox{0.9}{\tt 0x0c0000005} & 1 & ZipTimer-B\\\hline

\scalebox{0.9}{\tt 0x0c0000006} & 1 & ZipTimer-C\\\hline

\scalebox{0.9}{\tt 0x0c0000007} & 1 & ZipJiffies\\\hline

\scalebox{0.9}{\tt 0x0c0000008} & 1 & Master task counter\\\hline

\scalebox{0.9}{\tt 0x0c0000009} & 1 & Master prefetch stall counter\\\hline

\scalebox{0.9}{\tt 0x0c000000a} & 1 & Master memory stall counter\\\hline

\scalebox{0.9}{\tt 0x0c000000b} & 1 & Master instruction counter\\\hline

\scalebox{0.9}{\tt 0x0c000000c} & 1 & User task counter\\\hline

\scalebox{0.9}{\tt 0x0c000000d} & 1 & User prefetch stall counter\\\hline

\scalebox{0.9}{\tt 0x0c000000e} & 1 & User memory stall counter\\\hline

\scalebox{0.9}{\tt 0x0c000000f} & 1 & User instruction counter\\\hline

\scalebox{0.9}{\tt 0x0c0000010} & 1 & DMA command register\\\hline

\scalebox{0.9}{\tt 0x0c0000011} & 1 & DMA length\\\hline

\scalebox{0.9}{\tt 0x0c0000012} & 1 & DMA source address\\\hline

\scalebox{0.9}{\tt 0x0c0000013} & 1 & DMA destination address\\\hline

\scalebox{0.9}{\tt 0x0c0000040} & 1 & {\em Reserved for MMU context register}\\\hline

\scalebox{0.9}{\tt 0x0c0000080} & 32 & {\em Reserved for MMU TLB}\\\hline

\end{tabular}

\caption{ZipSystem Addresses}\label{tbl:zipio}

\end{center}\end{table}

\section{Peripheral I/O Control}

Tbl.~\ref{tbl:ioregs}

\begin{table}[htbp]

\begin{center}\begin{reglist}

VERSION  &\scalebox{0.8}{\tt 0x0100} & 32 & R & Build date\\\hline

PIC      &\scalebox{0.8}{\tt 0x0101} & 32 & R/W & Bus Interrupt Controller \\\hline

BUSERR   &\scalebox{0.8}{\tt 0x0102} & 32 & R & Last Bus Error Address\\\hline

PWRCOUNT &\scalebox{0.8}{\tt 0x0103} & 32 & R & Ticks since startup\\\hline

BTNSW    &\scalebox{0.8}{\tt 0x0104} & 32 & R/W & Button/Switch controller\\\hline

LEDCTRL  &\scalebox{0.8}{\tt 0x0105} & 32 & R/W & LED Controller \\\hline

AUXSETUP &\scalebox{0.8}{\tt 0x0106} & 29 & R/W & Auxilliary UART config\\\hline

GPSSETUP &\scalebox{0.8}{\tt 0x0107} & 29 & R/W & GPS UART config\\\hline

CLR-LEDx &\scalebox{0.8}{\tt 0x0108-b} & 32 & R/W & Color LED controller\\\hline

RTCDATE  &\scalebox{0.8}{\tt 0x010c} & 32 & R/W & BCD Calendar Date\\\hline

GPIO     &\scalebox{0.8}{\tt 0x010d} & 32 & R/W & GPIO controller\\\hline

UARTRX   &\scalebox{0.8}{\tt 0x010e} & 32 & R/W & Aux UART receive byte\\\hline

UARTTX   &\scalebox{0.8}{\tt 0x010f} & 32 & R/W & Aux UART transmit byte\\\hline

GPSRX    &\scalebox{0.8}{\tt 0x0110} & 32 & R/W & GPS UART receive byte\\\hline

GPSTX    &\scalebox{0.8}{\tt 0x0111} & 32 & R/W & GPS UART transmit byte\\\hline

% 0x010c-0x010f

\end{reglist}

\caption{I/O Peripheral Registers}\label{tbl:ioregs}

\end{center}\end{table}

shows the addresses of various I/O peripherals included as part of the SoC.

We'll walk through each of these peripherals in turn, describing how they work.

\subsection{Interrupt Controller}

The OpenArty design maintains three interrupt controllers.  Two of them

are found within the ZipSystem, and the third is located on the bus

itself.  Of these, the primary interrupt controller is located in the ZipSystem.

This interrupt controller accepts, as interrupt inputs, the outputs of both

the auxilliary interrupt controller as well as the bus interrupt controller.

Hence, even though the CPU only supports a single interrupt line, by using

these three interrupt controllers many more interrupts can be supported.

The primary interrupt controller handles interrupts from the sources listed

in Tbl.~\ref{tbl:sys-ints}.  These interrupts are listed together with the

mask that would need to be used when referencing them to the interrupt

controller.  In a similar fashion, the auxilliary interrupt controller accepts

inputs from the sources listed in Tbl.~\ref{tbl:aux-ints}.  Finally, the

bus interrupt controller handles the interrupts from the sources listed in

Tbl.~\ref{tbl:bus-ints}.

\begin{table}[htbp]

\begin{center}\begin{tabular}{|p{0.9in}|p{0.75in}|p{0.75in}|p{3.00in}|}\hline

\rowcolor[gray]{0.85} Name & Bit Mask & DMAC ID &Description \\\hline\hline

SYS\_DMAC  & 0x0001 && The DMA controller is idle.\\\hline

SYS\_JIF   & 0x0002 & 1 & A Jiffies timer has expired.\\\hline

SYS\_TMC   & 0x0004 & 2 & Timer C has timed out.\\\hline

SYS\_TMB   & 0x0008 & 3 & Timer C has timed out.\\\hline

SYS\_TMA   & 0x0010 & 4 & Timer C has timed out.\\\hline

SYS\_AUX   & 0x0020 & 5 & The auxilliary interrupt controller sends an interrupt\\\hline

SYS\_EXT   & 0x0040 & 6 & A Bus interrupt has tripped. \\\hline

SYS\_PPS   & 0x0080 & 7 & An interrupt marking the top of the second\\\hline

SYS\_GPSRX & 0x0100 & 8& A character has been received via GPS\\\hline

SYS\_NETRX & 0x0200 & 9 & A packet has been received via the network\\\hline

SYS\_NETTX & 0x0400 & 10 & The network controller is idle, having sent its

                        last packet\\\hline

SYS\_UARTRX & 0x0800 & 11 & A character has been received via the UART\\\hline

SYS\_UARTTX & 0x1000 & 12 & The transmit UART is idle, and ready for its next

                character.\\\hline

SYS\_SDCARD & 0x2000 & 13 & The SD-Card controller has become idle\\\hline

SYS\_BUTTON & 0x4000 & 14 & A Button has been pressed. \\\hline

\end{tabular}

\caption{Primary System Interrupts}\label{tbl:sys-ints}

\end{center}\end{table}

%%%%%%%%%%%%%

\begin{table}[htbp]

\begin{center}\begin{tabular}{|p{0.9in}|p{0.75in}|p{0.75in}|p{3.00in}|}\hline

\rowcolor[gray]{0.85} Name & Bit Mask & DMAC ID &Description \\\hline\hline

AUX\_UIC & 0x0001 & 16 & The user instruction counter has overflowed.\\\hline

AUX\_UPC & 0x0002 & 17 & The user prefetch stall counter has overflowed.\\\hline

AUX\_UOC & 0x0004 & 18 & The user ops stall counter has overflowed.\\\hline

AUX\_UTC & 0x0008 & 19 & The user clock tick counter has overflowed.\\\hline

AUX\_MIC & 0x0010 & 20 & The supervisor instruction counter has overflowed.\\\hline

AUX\_MPC & 0x0020 & 21 & The supervisor prefetch stall counter has overflowed.\\\hline

AUX\_MOC & 0x0040 & 22 & The supervisor ops stall counter has overflowed.\\\hline

AUX\_MTC & 0x0080 & 23 & The supervisor clock tick counter has overflowed.\\\hline

AUX\_SWITCH & 0x0100 & 24 & A switch has changed state\\\hline

AUX\_FLASH  & 0x0200 & 25 & The flash controller has completed a write/erase cycle\\\hline

AUX\_SCOPE & 0x0400 & 26 & The Scope has completed its collection\\\hline

AUX\_RTC    & 0x0800 & 27& An alarm or timer has taken place (assuming the RTC

                is installed, and includes both alarm or timer)\\\hline

AUX\_GPIO   & 0x1000 & 28 & The GPIO input lines have changed values.\\\hline

AUX\_OLED   & 0x2000 & 29 & The OLED driver is idle\\\hline

\end{tabular}

\caption{Auxilliary System Interrupts}\label{tbl:aux-ints}

\end{center}\end{table}

\begin{table}[htbp]

\begin{center}\begin{tabular}{|p{0.9in}|p{0.75in}|p{3.75in}|}\hline

\rowcolor[gray]{0.85} Name & Bit Mask & Description \\\hline\hline

BUS\_BUTTON & 0x0001 & A Button has been pressed. \\\hline

BUS\_SWITCH & 0x0002 & The Scope has completed its collection\\\hline

BUS\_PPS    & 0x0004 & Top of the second\\\hline

BUS\_RTC    & 0x0008 & An alarm or timer has taken place (assuming the RTC

                is installed, and includes both alarm or timer)\\\hline

BUS\_NETRX & 0x0010 & A packet has been received via the network\\\hline

BUS\_NETTX & 0x0020 & The network controller is idle, having sent its

                        last packet\\\hline

BUS\_UARTRX & 0x0040 & A character has been received via the UART\\\hline

BUS\_UARTTX & 0x0080 & The transmit UART is idle, and ready for its next

                character.\\\hline

BUS\_GPIO   & 0x0100 & The GPIO input lines have changed values.\\\hline

BUS\_FLASH  & 0x0200 & The flash device has finished either its erase or

                write cycle, and is ready for its next command. (Alternate

        config only.)\\\hline

BUS\_SCOPE  & 0x0400 & A scope has completed collecting.\\\hline

BUS\_GPSRX  & 0x0800 & A character has been received via GPS\\\hline

BUS\_SDCARD & 0x1000 & The SD-Card controller has become idle\\\hline

BUS\_OLED   & 0x2000 & The OLED interface has become idle\\\hline

BUS\_ZIP    & 0x4000 & True if the ZipCPU has come to a halt\\\hline

\end{tabular}

\caption{Bus Interrupts}\label{tbl:bus-ints}

\end{center}\end{table}

\subsection{Last Bus Error Address}

\subsection{General Purpose I/O}

\subsection{UART Data Register}

\section{Debugging Scopes}

\section{Internal Configuration Access Port}

\section{Real--Time Clock}

\section{On-Chip Block RAM}

\section{Flash Memory}

\begin{table}

\begin{center}\begin{reglist}

ewreg  &\scalebox{0.8}{\tt 0x0180} & 32 & R & Erase/write control and status\\\hline

status      &\scalebox{0.8}{\tt 0x0181} & 8 & R/W & Bus Interrupt Controller \\\hline

nvconf   &\scalebox{0.8}{\tt 0x0182} & 16 & R & Last Bus Error Address\\\hline

vconf &\scalebox{0.8}{\tt 0x0183} & 8 & R & Ticks since startup\\\hline

evonc    &\scalebox{0.8}{\tt 0x0184} & 8 & R/W & Button/Switch controller\\\hline

lock  &\scalebox{0.8}{\tt 0x0185} & 8 & R/W & LED Controller \\\hline

flagstatus&\scalebox{0.8}{\tt 0x0186} & 8 & R/W & Auxilliary UART config\\\hline

clear   &\scalebox{0.8}{\tt 0x0187} & 8 & R/W & Clear status on write\\\hline

Device ID &\scalebox{0.8}{\tt 0x0188-}\hfill & 5x32 & R & Device ID\\

        &\scalebox{0.8}{\tt -0x018c}\hfill & & & \\\hline

% asyncID &\scalebox{0.8}{\tt 0x018d} & 32 & R/W & Asynch Read ID.  Write starts the ASynch read, 0xff returned until complete\\\hline

asyncOTP  &\scalebox{0.8}{\tt 0x18e} & 32 & W & Asynch Read OTP.  Write starts the ASynch read, 0xff returned until complete\\\hline

OTP     &\scalebox{0.8}{\tt 0x0190-}\hfill &16x32 & R/W & OTP Memory\\

        &\scalebox{0.8}{\hfill\tt -0x19f} & & & \\\hline

% 0x010c-0x010f

\end{reglist}

\caption{Flash control registers}\label{tbl:flctl}

\end{center}\end{table}

\chapter{Wishbone}

The master and slave interfaces have been simplified with the following

requirement: the {\tt STB} line is not allowed to be high unless the {\tt CYC}

line is high.  In this fashion, a slave may often be able to ignore {\tt CYC}

and only act on the presence of {\tt STB}, knowing that {\tt CYC} must be

active at the same time.

\chapter{Clocks}

\begin{table}\begin{center}

\begin{clocklist}

{\tt i\_clk\_100mhz} & Ext & \multicolumn{2}{c|}{100~MHz} &

        100~MHz Crystal Oscillator \\\hline

{\tt s\_clk} & PLL & 200~MHz & & Internal Logic, Wishbone Clock \\\hline

{\tt ram\_clk} & PLL & 200~MHz & & DDR3 SDRAM Clock \\\hline

{\tt o\_sck} & Logic & 108~MHz & 50~MHz & QSPI Flash clock \\\hline

{\tt o\_sdclk} & Logic & 50~MHz & 100~kHz & SD--Card clock \\\hline

\end{clocklist}

\caption{OpenArty clocks}\label{tbl:clocks}

\end{center}\end{table}

\chapter{I/O Ports}

Table.~\ref{tbl:ioports}

\begin{table}[htbp]

\begin{center}

\begin{portlist}

i\_clk\_100mhz & 1 & Input & Clock\\\hline

o\_qspi\_cs\_n & 1 & Output & Quad SPI Flash chip select\\\hline

o\_qspi\_sck & 1 & Output & Quad SPI Flash clock\\\hline

io\_qspi\_dat & 4 & Input/Output & Four-wire SPI flash data bus\\\hline

i\_btn & 4 & Input  & Inputs from the two on-board push-buttons\\\hline

i\_sw  & 4 & Input  & Inputs from the two on-board push-buttons\\\hline

o\_led & 4 & Output & Outputs controlling the four on-board LED's\\\hline

o\_clr\_led0 & 3 & Output & \\\hline

o\_clr\_led1 & 3 & Output & \\\hline

o\_clr\_led2 & 3 & Output & \\\hline

o\_clr\_led3 & 3 & Output & \\\hline

i\_uart\_rx & 1 & Input &  UART receive input\\\hline

o\_uart\_tx & 1 & Output & UART transmit output\\\hline\hline

i\_aux\_rx & 1 & Input &  Auxiliary/Pmod UART receive input\\\hline

o\_aux\_tx & 1 & Output & Auxiliary/Pmod UART transmit output\\\hline

i\_aux\_rts & 1 & Input &  Auxiliary/Pmod UART receive input\\\hline

o\_aux\_cts & 1 & Output & Auxiliary/Pmod UART transmit output\\\hline\hline

i\_gps\_rx & 1 & Input &  GPS/Pmod UART receive input\\\hline

o\_gps\_tx & 1 & Output & GPS/Pmod UART transmit output\\\hline

i\_gps\_pps & 1 & Input & GPS Part-per-second (PPS) signal\\\hline

i\_gps\_3df & 1 & Input & GPS\\\hline\hline

o\_oled\_cs\_n & 1 & Output & \\\hline

o\_oled\_sck & 1 & Output & \\\hline

o\_oled\_mosi & 1 & Output & \\\hline

i\_oled\_miso & 1 & Input & \\\hline

o\_oled\_reset & 1 & Output & \\\hline

o\_oled\_dc & 1 & Output & \\\hline

o\_oled\_en & 1 & Output & \\\hline

o\_oled\_pmen & 1 & Output & \\\hline\hline

o\_sd\_sck & 1 & Output & SD Clock\\\hline

i\_sd\_cd & 1 & Input & Card Detect\\\hline

i\_sd\_wp & 1 & Input & Write Protect\\\hline

io\_cmd & 1 & In/Output & SD Bi-directional command wire\\\hline

io\_sd & 4 & In/Output & SD Bi-directional data lines\\\hline\hline

o\_cls\_cs\_n & 1 & Output & CLS Display chip select\\\hline

o\_cls\_sck & 1 & Output & CLS Display clock\\\hline

o\_cls\_mosi & 1 & Output & CLS Display MOSI\\\hline

i\_cls\_miso & 1 & Input & CLS Display MISO\\\hline\hline

\end{portlist}

\caption{List of IO ports}\label{tbl:ioports}

\end{center}\end{table}

lists the various I/O ports associated with OpenArty.

% Appendices

% Index

\end{document}