1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
|
<table class="head">
<tr>
<td class="head-ltitle">DS1307(4)</td>
<td class="head-vol">Device Drivers Manual</td>
<td class="head-rtitle">DS1307(4)</td>
</tr>
</table>
<div class="manual-text">
<section class="Sh">
<h1 class="Sh" id="NAME"><a class="permalink" href="#NAME">NAME</a></h1>
<p class="Pp"><code class="Nm">ds1307</code> — <span class="Nd">64 x 8,
serial, i2c real-time clock (RTC)</span></p>
</section>
<section class="Sh">
<h1 class="Sh" id="SYNOPSIS"><a class="permalink" href="#SYNOPSIS">SYNOPSIS</a></h1>
<p class="Pp"><code class="Cd">device iic</code>
<br/>
<code class="Cd">device iicbus</code>
<br/>
<code class="Cd">device ds1307</code></p>
</section>
<section class="Sh">
<h1 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h1>
<p class="Pp">The <code class="Nm">ds1307</code> serial real-time clock (RTC) is
a low-power, full binary-coded decimal (BCD) clock/calendar plus 56 bytes of
NV SRAM.</p>
<p class="Pp">The <code class="Nm">ds1307</code> has a built-in power-sense
circuit that detects power failures and automatically switches to the backup
supply. Timekeeping operation continues while the part operates from the
backup supply.</p>
<p class="Pp">Access to <code class="Nm">ds1307</code> settings is made with the
<a class="Xr">sysctl(8)</a> interface:</p>
<div class="Bd Pp Li">
<pre>dev.ds1307.0.%desc: Maxim DS1307 RTC
dev.ds1307.0.%driver: ds1307
dev.ds1307.0.%location: addr=0xd0
dev.ds1307.0.%pnpinfo: name=rtc compat=maxim,ds1307
dev.ds1307.0.%parent: iicbus1
dev.ds1307.0.sqwe: 1
dev.ds1307.0.sqw_freq: 32768
dev.ds1307.0.sqw_out: 0</pre>
</div>
<dl class="Bl-tag">
<dt id="dev.ds1307._d.sqwe"><var class="Va">dev.ds1307.%d.sqwe</var></dt>
<dd>If set to 1, the SQW pin drives a square-wave of
<var class="Va">dev.ds1307.%d.sqw_freq</var> frequency. If set to 0, the
output level of SQW pin is controlled by
<var class="Va">dev.ds1307.%d.sqw_out</var>.</dd>
<dt id="dev.ds1307._d.sqw_freq"><var class="Va">dev.ds1307.%d.sqw_freq</var></dt>
<dd>Select the frequency of the SQW pin when the square-wave output is enabled
on <var class="Va">dev.ds1307.%d.sqwe</var>. It can be set to 1, 4096,
8192 and 32768.</dd>
<dt id="dev.ds1307._d.sqw_out"><var class="Va">dev.ds1307.%d.sqw_out</var></dt>
<dd>Set the output level of the SQW pin when
<var class="Va">dev.ds1307.%d.sqwe</var> is set to 0.</dd>
</dl>
<p class="Pp">Please check the <code class="Nm">ds1307</code> datasheet for more
details.</p>
<p class="Pp">On a <a class="Xr">device.hints(5)</a> based system, such as
<code class="Li">MIPS</code>, these values are configurable for
<code class="Nm">ds1307</code>:</p>
<dl class="Bl-tag">
<dt id="hint.ds1307._d.at"><var class="Va">hint.ds1307.%d.at</var></dt>
<dd>The <a class="Xr">iicbus(4)</a> that the <code class="Nm">ds1307</code> is
connected to.</dd>
<dt id="hint.ds1307._d.addr"><var class="Va">hint.ds1307.%d.addr</var></dt>
<dd>The i2c address of <code class="Nm">ds1307</code>.</dd>
</dl>
<p class="Pp">On a <a class="Xr">FDT(4)</a> based system the following
properties must be set:</p>
<dl class="Bl-tag">
<dt id="compatible"><var class="Va">compatible</var></dt>
<dd>Must always be set to "dallas,ds1307" or
"maxim,ds1307".</dd>
<dt id="reg"><var class="Va">reg</var></dt>
<dd>The i2c address of <code class="Nm">ds1307</code>. The default address for
<code class="Nm">ds1307</code> is 0xd0.</dd>
</dl>
</section>
<section class="Sh">
<h1 class="Sh" id="SEE_ALSO"><a class="permalink" href="#SEE_ALSO">SEE
ALSO</a></h1>
<p class="Pp"><a class="Xr">fdt(4)</a>, <a class="Xr">iic(4)</a>,
<a class="Xr">iicbus(4)</a>, <a class="Xr">sysctl(8)</a></p>
</section>
<section class="Sh">
<h1 class="Sh" id="HISTORY"><a class="permalink" href="#HISTORY">HISTORY</a></h1>
<p class="Pp">The <code class="Nm">ds1307</code> driver first appeared in
<span class="Ux">FreeBSD 11.0</span>.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="AUTHORS"><a class="permalink" href="#AUTHORS">AUTHORS</a></h1>
<p class="Pp">The <code class="Nm">ds1307</code> driver and this manual page
were written by <span class="An">Luiz Otavio O Souza</span>
<<a class="Mt" href="mailto:loos@FreeBSD.org">loos@FreeBSD.org</a>>.</p>
</section>
</div>
<table class="foot">
<tr>
<td class="foot-date">December 10, 2024</td>
<td class="foot-os">FreeBSD 15.0</td>
</tr>
</table>
|
