ZealOS/docs/Doc/PIT.html

<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=US-ASCII">
<meta name="generator" content="ZealOS V0.05">
<style type="text/css">
body {background-color:#000000;}
.cF0{color:#ffffff;background-color:#000000;}
.cF1{color:#3465a4;background-color:#000000;}
.cF2{color:#4e9a06;background-color:#000000;}
.cF3{color:#06989a;background-color:#000000;}
.cF4{color:#a24444;background-color:#000000;}
.cF5{color:#75507b;background-color:#000000;}
.cF6{color:#ce982f;background-color:#000000;}
.cF7{color:#bcc0b9;background-color:#000000;}
.cF8{color:#555753;background-color:#000000;}
.cF9{color:#729fcf;background-color:#000000;}
.cFA{color:#82bc49;background-color:#000000;}
.cFB{color:#34e2e2;background-color:#000000;}
.cFC{color:#ac3535;background-color:#000000;}
.cFD{color:#ad7fa8;background-color:#000000;}
.cFE{color:#fce94f;background-color:#000000;}
.cFF{color:#000000;background-color:#000000;}
</style>
</head>
<body>
<pre style="font-family:courier;font-size:10pt">
<a name="l1"></a><span class=cF0>The </span><span class=cF2>Programmable Interval Timer</span><span class=cF0> has two purposes: Generate interrupts, and control the </span><span class=cF2>PC speaker</span><span class=cF0>.
<a name="l2"></a>
<a name="l3"></a>It has 3 channels:
<a name="l4"></a></span><span class=cF4>
<a name="l5"></a></span><a href="https://tomawezome.github.io/ZealOS/Kernel/KernelA.html#l685"><span class=cF4>Channel 0</span></a><span class=cF0> can generate an interrupt, IRQ 0, at a defined frequency. We set it up in </span><a href="https://tomawezome.github.io/ZealOS/Kernel/KMain.html#l124"><span class=cF4>TimerInit</span></a><span class=cF0>(), and use it in </span><a href="https://tomawezome.github.io/ZealOS/Kernel/KMisc.html#l22"><span class=cF4>SysTimerRead</span></a><span class=cF0>().
<a name="l6"></a>
<a name="l7"></a>Channel 1 was used historically to refresh the DRAM, but now it is obsolete as the hardware does this itself.  Channel 1 is 
<a name="l8"></a>useless and might not even be implemented anymore on modern machines.
<a name="l9"></a></span><span class=cF4>
<a name="l10"></a></span><a href="https://tomawezome.github.io/ZealOS/Kernel/KernelA.html#l686"><span class=cF4>Channel 2</span></a><span class=cF0>'s output is connected to the PC speaker.
<a name="l11"></a>
<a name="l12"></a>The Command port is used to control each of these 3 channels. The relevant </span><a href="https://tomawezome.github.io/ZealOS/Kernel/KernelA.html#l689"><span class=cF4>flags</span></a><span class=cF0> are defined.
<a name="l13"></a>
<a name="l14"></a>See </span><a href="https://tomawezome.github.io/ZealOS/Kernel/KMisc.html#l129"><span class=cF4>Sound</span></a><span class=cF0>() for how the PC speaker frequency is changed.</span></pre></body>
</html>
Implement codebase HTML generation. 2021-07-03 05:07:57 +01:00			`<!DOCTYPE HTML>`
			`<html>`
			`<head>`
			`<meta http-equiv="Content-Type" content="text/html;charset=US-ASCII">`
			`<meta name="generator" content="ZealOS V0.05">`
			`<style type="text/css">`
			`body {background-color:#000000;}`
			`.cF0{color:#ffffff;background-color:#000000;}`
			`.cF1{color:#3465a4;background-color:#000000;}`
			`.cF2{color:#4e9a06;background-color:#000000;}`
			`.cF3{color:#06989a;background-color:#000000;}`
			`.cF4{color:#a24444;background-color:#000000;}`
			`.cF5{color:#75507b;background-color:#000000;}`
			`.cF6{color:#ce982f;background-color:#000000;}`
			`.cF7{color:#bcc0b9;background-color:#000000;}`
			`.cF8{color:#555753;background-color:#000000;}`
			`.cF9{color:#729fcf;background-color:#000000;}`
			`.cFA{color:#82bc49;background-color:#000000;}`
			`.cFB{color:#34e2e2;background-color:#000000;}`
			`.cFC{color:#ac3535;background-color:#000000;}`
			`.cFD{color:#ad7fa8;background-color:#000000;}`
			`.cFE{color:#fce94f;background-color:#000000;}`
			`.cFF{color:#000000;background-color:#000000;}`
			`</style>`
			`</head>`
			`<body>`
			`<pre style="font-family:courier;font-size:10pt">`
			`<a name="l1"></a><span class=cF0>The </span><span class=cF2>Programmable Interval Timer</span><span class=cF0> has two purposes: Generate interrupts, and control the </span><span class=cF2>PC speaker</span><span class=cF0>.`
			`<a name="l2"></a>`
			`<a name="l3"></a>It has 3 channels:`
			`<a name="l4"></a></span><span class=cF4>`
Implement OS Upgrade wizard. Make HTML doc generation force index files to make links from subdirectories. Added Sixto-Clementine Vulgate Bible to Misc/. Fix User window height, patch font chars. 2021-07-04 06:19:15 +01:00			<a name="l5"></a></span><a href="https://tomawezome.github.io/ZealOS/Kernel/KernelA.html#l685"><span class=cF4>Channel 0</span></a><span class=cF0> can generate an interrupt, IRQ 0, at a defined frequency. We set it up in </span><a href="https://tomawezome.github.io/ZealOS/Kernel/KMain.html#l124"><span class=cF4>TimerInit</span></a><span class=cF0>(), and use it in </span><a href="https://tomawezome.github.io/ZealOS/Kernel/KMisc.html#l22"><span class=cF4>SysTimerRead</span></a><span class=cF0>().
Implement codebase HTML generation. 2021-07-03 05:07:57 +01:00			`<a name="l6"></a>`
			`<a name="l7"></a>Channel 1 was used historically to refresh the DRAM, but now it is obsolete as the hardware does this itself. Channel 1 is`
			`<a name="l8"></a>useless and might not even be implemented anymore on modern machines.`
			`<a name="l9"></a></span><span class=cF4>`
Fix codebase HTML generation. 2021-07-03 07:51:43 +01:00			`<a name="l10"></a></span><a href="https://tomawezome.github.io/ZealOS/Kernel/KernelA.html#l686"><span class=cF4>Channel 2</span></a><span class=cF0>'s output is connected to the PC speaker.`
Implement codebase HTML generation. 2021-07-03 05:07:57 +01:00			`<a name="l11"></a>`
Fix codebase HTML generation. 2021-07-03 07:51:43 +01:00			`<a name="l12"></a>The Command port is used to control each of these 3 channels. The relevant </span><a href="https://tomawezome.github.io/ZealOS/Kernel/KernelA.html#l689"><span class=cF4>flags</span></a><span class=cF0> are defined.`
Implement codebase HTML generation. 2021-07-03 05:07:57 +01:00			`<a name="l13"></a>`
Fix codebase HTML generation. 2021-07-03 07:51:43 +01:00			`<a name="l14"></a>See </span><a href="https://tomawezome.github.io/ZealOS/Kernel/KMisc.html#l129"><span class=cF4>Sound</span></a><span class=cF0>() for how the PC speaker frequency is changed.</span></pre></body>`
Implement codebase HTML generation. 2021-07-03 05:07:57 +01:00			`</html>`