You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
199 lines
6.0 KiB
HTML
199 lines
6.0 KiB
HTML
4 years ago
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||
|
|
<html>
|
||
|
|
<!-- Created by GNU Texinfo 6.4, http://www.gnu.org/software/texinfo/ -->
|
||
|
|
<head>
|
||
|
|
<title>Debugging (Embed with GNU)</title>
|
||
|
|
|
||
|
|
<meta name="description" content="Debugging (Embed with GNU)">
|
||
|
|
<meta name="keywords" content="Debugging (Embed with GNU)">
|
||
|
|
<meta name="resource-type" content="document">
|
||
|
|
<meta name="distribution" content="global">
|
||
|
|
<meta name="Generator" content="makeinfo">
|
||
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
|
||
|
|
<link href="index.html#Top" rel="start" title="Top">
|
||
|
|
<link href="leds_002ec.html#SEC_Contents" rel="contents" title="Table of Contents">
|
||
|
|
<link href="Libc.html#Libc" rel="up" title="Libc">
|
||
|
|
<link href="GDB.html#GDB" rel="next" title="GDB">
|
||
|
|
<link href="Misc-Support.html#Misc-Support" rel="prev" title="Misc Support">
|
||
|
|
<style type="text/css">
|
||
|
|
<!--
|
||
|
|
a.summary-letter {text-decoration: none}
|
||
|
|
blockquote.indentedblock {margin-right: 0em}
|
||
|
|
blockquote.smallindentedblock {margin-right: 0em; font-size: smaller}
|
||
|
|
blockquote.smallquotation {font-size: smaller}
|
||
|
|
div.display {margin-left: 3.2em}
|
||
|
|
div.example {margin-left: 3.2em}
|
||
|
|
div.lisp {margin-left: 3.2em}
|
||
|
|
div.smalldisplay {margin-left: 3.2em}
|
||
|
|
div.smallexample {margin-left: 3.2em}
|
||
|
|
div.smalllisp {margin-left: 3.2em}
|
||
|
|
kbd {font-style: oblique}
|
||
|
|
pre.display {font-family: inherit}
|
||
|
|
pre.format {font-family: inherit}
|
||
|
|
pre.menu-comment {font-family: serif}
|
||
|
|
pre.menu-preformatted {font-family: serif}
|
||
|
|
pre.smalldisplay {font-family: inherit; font-size: smaller}
|
||
|
|
pre.smallexample {font-size: smaller}
|
||
|
|
pre.smallformat {font-family: inherit; font-size: smaller}
|
||
|
|
pre.smalllisp {font-size: smaller}
|
||
|
|
span.nolinebreak {white-space: nowrap}
|
||
|
|
span.roman {font-family: initial; font-weight: normal}
|
||
|
|
span.sansserif {font-family: sans-serif; font-weight: normal}
|
||
|
|
ul.no-bullet {list-style: none}
|
||
|
|
-->
|
||
|
|
</style>
|
||
|
|
|
||
|
|
|
||
|
|
</head>
|
||
|
|
|
||
|
|
<body lang="en">
|
||
|
|
<a name="Debugging"></a>
|
||
|
|
<div class="header">
|
||
|
|
<p>
|
||
|
|
Previous: <a href="Misc-Support.html#Misc-Support" accesskey="p" rel="prev">Misc Support</a>, Up: <a href="Libc.html#Libc" accesskey="u" rel="up">Libc</a> [<a href="leds_002ec.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>]</p>
|
||
|
|
</div>
|
||
|
|
<hr>
|
||
|
|
<a name="Useful-debugging-functions"></a>
|
||
|
|
<h4 class="subsection">3.4.4 Useful debugging functions</h4>
|
||
|
|
|
||
|
|
<p>There are always a few useful functions for debugging your project in
|
||
|
|
progress. I typically implement a simple <code>print()</code> routine that
|
||
|
|
runs standalone in liblgoss, with no <code>newlib</code> support. The I/O
|
||
|
|
function <code>outbyte()</code> can also be used for low level debugging. Many
|
||
|
|
times print will work when there are problems that cause <code>printf()</code> to
|
||
|
|
cause an exception. <code>putnum()</code> is just to print out values in hex
|
||
|
|
so they are easier to read.
|
||
|
|
</p>
|
||
|
|
<div class="smallexample">
|
||
|
|
<pre class="smallexample">/*
|
||
|
|
* print -- do a raw print of a string
|
||
|
|
*/
|
||
|
|
int
|
||
|
|
print(ptr)
|
||
|
|
char *ptr;
|
||
|
|
{
|
||
|
|
while (*ptr) {
|
||
|
|
outbyte (*ptr++);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* putnum -- print a 32 bit number in hex
|
||
|
|
*/
|
||
|
|
int
|
||
|
|
putnum (num)
|
||
|
|
unsigned int num;
|
||
|
|
{
|
||
|
|
char buffer[9];
|
||
|
|
int count;
|
||
|
|
char *bufptr = buffer;
|
||
|
|
int digit;
|
||
|
|
|
||
|
|
for (count = 7 ; count >= 0 ; count--) {
|
||
|
|
digit = (num >> (count * 4)) & 0xf;
|
||
|
|
|
||
|
|
if (digit <= 9)
|
||
|
|
*bufptr++ = (char) ('0' + digit);
|
||
|
|
else
|
||
|
|
*bufptr++ = (char) ('a' - 10 + digit);
|
||
|
|
}
|
||
|
|
|
||
|
|
*bufptr = (char) 0;
|
||
|
|
print (buffer);
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
<p>If there are LEDs on the board, they can also be put to use for
|
||
|
|
debugging when the serial I/O code is being written. I usually implement
|
||
|
|
a <code>zylons()</code> function, which strobes the LEDS (if there is more
|
||
|
|
than one) in sequence, creating a rotating effect. This is convenient
|
||
|
|
between I/O to see if the target is still alive. Another useful LED
|
||
|
|
function is <code>led_putnum()</code>, which takes a digit and displays it as
|
||
|
|
a bit pattern or number. These usually have to be written in assembler
|
||
|
|
for each target board. Here are a number of C based routines that may be
|
||
|
|
useful.
|
||
|
|
</p>
|
||
|
|
<p><code>led_putnum()</code> puts a number on a single digit segmented
|
||
|
|
LED display. This LED is set by setting a bit mask to an address, where
|
||
|
|
1 turns the segment off, and 0 turns it on. There is also a little
|
||
|
|
decimal point on the LED display, so it gets the leftmost bit. The other
|
||
|
|
bits specify the segment location. The bits look like:
|
||
|
|
</p>
|
||
|
|
<div class="smallexample">
|
||
|
|
<pre class="smallexample"> [d.p | g | f | e | d | c | b | a ] is the byte.
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
<p>The locations are set up as:
|
||
|
|
</p>
|
||
|
|
<div class="smallexample">
|
||
|
|
<pre class="smallexample"> a
|
||
|
|
-----
|
||
|
|
f | | b
|
||
|
|
| g |
|
||
|
|
-----
|
||
|
|
| |
|
||
|
|
e | | c
|
||
|
|
-----
|
||
|
|
d
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
<p>This takes a number that’s already been converted to a string, and
|
||
|
|
prints it.
|
||
|
|
</p>
|
||
|
|
<div class="smallexample">
|
||
|
|
<pre class="smallexample">#define LED_ADDR 0xd00003
|
||
|
|
|
||
|
|
void
|
||
|
|
led_putnum ( num )
|
||
|
|
char num;
|
||
|
|
{
|
||
|
|
static unsigned char *leds = (unsigned char *)LED_ADDR;
|
||
|
|
static unsigned char num_bits [18] = {
|
||
|
|
0xff, /* clear all */
|
||
|
|
0xc0, 0xf9, 0xa4, 0xb0, 0x99, 0x92, 0x82, 0xf8, 0x80, 0x98, /* numbers 0-9 */
|
||
|
|
0x98, 0x20, 0x3, 0x27, 0x21, 0x4, 0xe /* letters a-f */
|
||
|
|
};
|
||
|
|
|
||
|
|
if (num >= '0' && num <= '9')
|
||
|
|
num = (num - '0') + 1;
|
||
|
|
|
||
|
|
if (num >= 'a' && num <= 'f')
|
||
|
|
num = (num - 'a') + 12;
|
||
|
|
|
||
|
|
if (num == ' ')
|
||
|
|
num = 0;
|
||
|
|
|
||
|
|
*leds = num_bits[num];
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* zylons -- draw a rotating pattern. NOTE: this function never returns.
|
||
|
|
*/
|
||
|
|
void
|
||
|
|
zylons()
|
||
|
|
{
|
||
|
|
unsigned char *leds = (unsigned char *)LED_ADDR;
|
||
|
|
unsigned char curled = 0xfe;
|
||
|
|
|
||
|
|
while (1)
|
||
|
|
{
|
||
|
|
*leds = curled;
|
||
|
|
curled = (curled >> 1) | (curled << 7);
|
||
|
|
delay ( 200 );
|
||
|
|
}
|
||
|
|
}
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
|
||
|
|
<hr>
|
||
|
|
<div class="header">
|
||
|
|
<p>
|
||
|
|
Previous: <a href="Misc-Support.html#Misc-Support" accesskey="p" rel="prev">Misc Support</a>, Up: <a href="Libc.html#Libc" accesskey="u" rel="up">Libc</a> [<a href="leds_002ec.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>]</p>
|
||
|
|
</div>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
</body>
|
||
|
|
</html>
|