Massive blog regeneration. RBUS-related posts.

author: Chris Xiong <chirs241097@gmail.com> 2024-02-17 20:44:52 -0500
committer: Chris Xiong <chirs241097@gmail.com> 2024-02-17 20:44:52 -0500
commit: 891f8eee12e6bdb2fad0fe0b28976362eb965236 (patch)
tree: 8a78ffa14ecf3c8893fbfd441cf50b1978ee33cd /blog/post/2024-02-02.html
parent: d5e40e5890cd99144a44e2922fd97ddaa9968c14 (diff)
download: web-891f8eee12e6bdb2fad0fe0b28976362eb965236.tar.xz
1 files changed, 610 insertions, 0 deletions
diff --git a/blog/post/2024-02-02.html b/blog/post/2024-02-02.html
new file mode 100644
index 0000000..db66d21
--- /dev/null
+++ b/blog/post/2024-02-02.html
@@ -0,0 +1,610 @@
+<!DOCTYPE html><html><head>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width,initial-scale=1">
+<meta name="theme-color" content="#000000">
+<title>Chrisoft::Blog</title>
+<script type="text/javascript" src="/panel.js"></script>
+<script type="text/javascript" src="/themer.js"></script>
+<script type="text/javascript" src="/blog/footnoter.js"></script>
+<script type="text/javascript" src="/blog/aes-js.js"></script>
+<script type="text/javascript" src="/blog/scrypt.js"></script>
+<script type="text/javascript" src="/blog/sha256.js"></script>
+<script type="text/javascript" src="/blog/decryptor.js"></script>
+<link rel="stylesheet" type="text/css" href="/common.css">
+<link rel="stylesheet" type="text/css" href="/panel.css">
+<link rel="stylesheet" type="text/css" href="/theme0a.css" id="theme0a">
+<link rel="stylesheet" type="text/css" href="/theme0b.css" id="theme0b">
+<link rel="stylesheet" type="text/css" href="/theme1a.css" id="theme1a">
+<link rel="stylesheet" type="text/css" href="/theme1b.css" id="theme1b">
+<link rel="stylesheet" type="text/css" href="/theme2a.css" id="theme2a">
+<link rel="stylesheet" type="text/css" href="/theme2b.css" id="theme2b">
+<link rel="stylesheet" type="text/css" href="/theme3a.css" id="theme3a">
+<link rel="stylesheet" type="text/css" href="/theme3b.css" id="theme3b">
+<link rel="stylesheet" type="text/css" href="/blog/blogext.css">
+<script>
+function ol()
+{
+	window.onresize=function()
+	{
+		if(window.innerWidth<768)
+		setupevents();
+		else unsetevents();
+	}
+	window.onresize();
+	loadTheme();
+	_decryptonload();
+}
+</script>
+<style>
+table tr:nth-child(odd) { background-color: rgba(160, 160, 160, 0.3); }
+</style></head>
+<body onload="ol()" style="overflow-x:hidden;">
+	<div id="panel" class="TText">
+		<ul id="panellist">
+			<li><a href="/"><h1>Chrisoft</h1></a></li>
+			<li><a href="/blog"><h2>Blog</h2></a></li>
+			<li><a href="#"><h3 id="title">R-BUS Technical Information</h3></a></li>
+			<li><span>Tags</span>
+			<ul id="tagslist">
+			<li><a href="/blog/list/music/">music</a></li><li><a href="/blog/list/electronics/">electronics</a></li></ul>
+			</li>
+			<li id="tocouter">
+				<span>Table of Contents</span>
+				<ul id="tocroot">
+				<li><a class="toctarg" href="#tocanch0">Background</a></li><li><a class="toctarg" href="#tocanch1">Devices with R-BUS support</a></li><li><a class="toctarg" href="#tocanch2">Pin definition</a></li><li><a class="toctarg" href="#tocanch3">Official cable wiring</a></li><li><a class="toctarg" href="#tocanch4">Electrical
+characteristics of the interface</a></li><li><ul class="tocnode"><li><a class="toctarg" href="#tocanch5">Power</a></li><li><a class="toctarg" href="#tocanch6">Digital Audio</a></li><li><a class="toctarg" href="#tocanch7">MIDI</a></li></ul></li></ul>
+			</li>
+			<li style="margin-left:-0.5em"><a id="prevp" href="2023-11-13.html">Prev post</a></li>
+			<li style="margin-left:-0.5em"><a id="nextp" href="2024-02-04.html">Next post</a></li>
+		</ul>
+	</div>
+	<div id="content">
+		<h2 id="titleh" class="TText" style="font-wight:normal;">R-BUS Technical Information</h2>
+		<div id="datetags" class="TText" style="margin-bottom:1em;">2024-02-02<br>#music #electronics</div>
+		<hr><div id="article" class="TText">
+<article>
+<h2 id="tocanch0" class="tvis">Background</h2>
+<p>R-BUS (also called RMDB2 / RMDB II on older products) is an obsolete
+proprietary interconnect format that carries bidirectional MIDI and
+digital audio data created by Roland. It was used on Roland products
+released from the late 90s to early 2000s.</p>
+<p>There was a physically incompatible and much rarer predecessor of
+R-BUS called RMDB (Roland Multipurpose Digital Bus). RMDB is not the
+subject of this article.</p>
+<p>Much of the information here is gathered from schematics inside
+service manuals for various Roland products, mainly the XV-5080 and
+VS-2400. These can be easily found with a search through the
+interwebz.</p>
+<p>This article assumes minimal electronics knowledge from the reader.
+As a matter of fact, the author is also a layperson in this space.
+Report of any issues in the article would be appreciated.</p>
+<p>For other R-BUS related stuff on this website, please visit <a href="/rbusif">this page</a>.</p>
+<h2 id="tocanch1" class="tvis">Devices with R-BUS support</h2>
+<p>Here is a not necessarily complete list of Roland products that comes
+with at least one R-BUS connector:</p>
+<ul>
+<li>Mixing Console
+<ul>
+<li>VM-3100Pro</li>
+<li>VM-7100 / VM-7200 (3 ports on optional VM-24E I/O expansion)</li>
+</ul></li>
+<li>Studio Workstation
+<ul>
+<li>VS-2400</li>
+<li>VS-2480 (2 ports)</li>
+<li>VSR-880</li>
+</ul></li>
+<li>Production Studio
+<ul>
+<li>MV-8000 / MV-8800 (available through the MV8-OP1 audio I/O
+expansion)</li>
+</ul></li>
+<li>Synthesizer
+<ul>
+<li>XV-5080 (output only)</li>
+</ul></li>
+<li>Interface Modules
+<ul>
+<li>RPC-1 (Conventional PCI R-BUS interface)</li>
+<li>ADA-7000 (A/D converter)</li>
+<li>AE-7000 (R-BUS &lt;=&gt; AES/EBU converter)</li>
+<li>DIF-AT (R-BUS &lt;=&gt; TDIF &amp; ADAT converter)</li>
+<li>DIF-AT24 (R-BUS to ADAT and MIDI interface, 24-bit)</li>
+</ul></li>
+</ul>
+<h2 id="tocanch2" class="tvis">Pin definition</h2>
+<p>Connection for VS-2400 and XV-5080 is extracted from their respective
+service manuals. Pin usage inferred from these connections.</p>
+<table>
+<colgroup>
+<col style="width: 13%">
+<col style="width: 31%">
+<col style="width: 31%">
+<col style="width: 22%">
+</colgroup>
+<thead>
+<tr class="header">
+<th style="text-align: center;">PIN</th>
+<th style="text-align: center;">VS-2400</th>
+<th style="text-align: center;">XV-5080</th>
+<th style="text-align: left;">Usage</th>
+</tr>
+</thead>
+<tbody>
+<tr class="odd">
+<td style="text-align: center;">1</td>
+<td style="text-align: center;">+5V</td>
+<td style="text-align: center;">+5V</td>
+<td style="text-align: left;">Power output</td>
+</tr>
+<tr class="even">
+<td style="text-align: center;">2</td>
+<td style="text-align: center;">RBOUT11</td>
+<td style="text-align: center;">SDO4</td>
+<td style="text-align: left;">Channel 1/2 output (<span style="text-decoration: overline;">SDOUT1</span><a id="n1" href="#note1" class="note">[1]</a>)</td>
+</tr>
+<tr class="odd">
+<td style="text-align: center;">3</td>
+<td style="text-align: center;">RBOUT12</td>
+<td style="text-align: center;">SDO5</td>
+<td style="text-align: left;">Channel 3/4 output (<span style="text-decoration: overline;">SDOUT2</span>)</td>
+</tr>
+<tr class="even">
+<td style="text-align: center;">4</td>
+<td style="text-align: center;">RBOUT13</td>
+<td style="text-align: center;">SDO6</td>
+<td style="text-align: left;">Channel 5/6 output (<span style="text-decoration: overline;">SDOUT3</span>)</td>
+</tr>
+<tr class="odd">
+<td style="text-align: center;">5</td>
+<td style="text-align: center;">GND</td>
+<td style="text-align: center;">GND</td>
+<td style="text-align: left;">Ground</td>
+</tr>
+<tr class="even">
+<td style="text-align: center;">6</td>
+<td style="text-align: center;">RBOUT14</td>
+<td style="text-align: center;">SDO7</td>
+<td style="text-align: left;">Channel 7/8 output (<span style="text-decoration: overline;">SDOUT4</span>)</td>
+</tr>
+<tr class="odd">
+<td style="text-align: center;">7</td>
+<td style="text-align: center;">NC <a id="n2" href="#note2" class="note">[2]</a></td>
+<td style="text-align: center;">NC</td>
+<td style="text-align: left;">Unused?</td>
+</tr>
+<tr class="even">
+<td style="text-align: center;">8</td>
+<td style="text-align: center;">RBIN14</td>
+<td style="text-align: center;">NC</td>
+<td style="text-align: left;">Channel 7/8 input (<span style="text-decoration: overline;">SDIN4</span>)</td>
+</tr>
+<tr class="odd">
+<td style="text-align: center;">9</td>
+<td style="text-align: center;">GND</td>
+<td style="text-align: center;">GND</td>
+<td style="text-align: left;">Ground</td>
+</tr>
+<tr class="even">
+<td style="text-align: center;">10</td>
+<td style="text-align: center;">RBIN13</td>
+<td style="text-align: center;">NC</td>
+<td style="text-align: left;">Channel 5/6 input (<span style="text-decoration: overline;">SDIN3</span>)</td>
+</tr>
+<tr class="odd">
+<td style="text-align: center;">11</td>
+<td style="text-align: center;">RBIN12</td>
+<td style="text-align: center;">NC</td>
+<td style="text-align: left;">Channel 3/4 input (<span style="text-decoration: overline;">SDIN2</span>)</td>
+</tr>
+<tr class="even">
+<td style="text-align: center;">12</td>
+<td style="text-align: center;">RBIN11</td>
+<td style="text-align: center;">SDI2</td>
+<td style="text-align: left;">Channel 1/2 input (<span style="text-decoration: overline;">SDIN1</span>)</td>
+</tr>
+<tr class="odd">
+<td style="text-align: center;">13</td>
+<td style="text-align: center;">NC</td>
+<td style="text-align: center;">NC</td>
+<td style="text-align: left;">Power reception for bus-powered devices
+<a id="n3" href="#note3" class="note">[3]</a></td>
+</tr>
+<tr class="even">
+<td style="text-align: center;">14</td>
+<td style="text-align: center;">PC_TXD1</td>
+<td style="text-align: center;">RBUS_TX</td>
+<td style="text-align: left;">MIDI transmit <a id="n4" href="#note4" class="note">[4]</a></td>
+</tr>
+<tr class="odd">
+<td style="text-align: center;">15</td>
+<td style="text-align: center;">GND</td>
+<td style="text-align: center;">GND</td>
+<td style="text-align: left;">Ground</td>
+</tr>
+<tr class="even">
+<td style="text-align: center;">16</td>
+<td style="text-align: center;">GND</td>
+<td style="text-align: center;">GND</td>
+<td style="text-align: left;">Ground</td>
+</tr>
+<tr class="odd">
+<td style="text-align: center;">17</td>
+<td style="text-align: center;">GND</td>
+<td style="text-align: center;">GND</td>
+<td style="text-align: left;">Ground</td>
+</tr>
+<tr class="even">
+<td style="text-align: center;">18</td>
+<td style="text-align: center;">1FS</td>
+<td style="text-align: center;">LRCK4</td>
+<td style="text-align: left;">Frame sync (word clock) output</td>
+</tr>
+<tr class="odd">
+<td style="text-align: center;">19</td>
+<td style="text-align: center;">GND</td>
+<td style="text-align: center;">GND</td>
+<td style="text-align: left;">Ground</td>
+</tr>
+<tr class="even">
+<td style="text-align: center;">20</td>
+<td style="text-align: center;">GND</td>
+<td style="text-align: center;">GND</td>
+<td style="text-align: left;">Ground</td>
+</tr>
+<tr class="odd">
+<td style="text-align: center;">21</td>
+<td style="text-align: center;">RBFS1</td>
+<td style="text-align: center;">RBUS-WDCLK</td>
+<td style="text-align: left;">Frame sync (word clock) input</td>
+</tr>
+<tr class="even">
+<td style="text-align: center;">22</td>
+<td style="text-align: center;">GND</td>
+<td style="text-align: center;">GND</td>
+<td style="text-align: left;">Ground</td>
+</tr>
+<tr class="odd">
+<td style="text-align: center;">23</td>
+<td style="text-align: center;">GND</td>
+<td style="text-align: center;">GND</td>
+<td style="text-align: left;">Ground</td>
+</tr>
+<tr class="even">
+<td style="text-align: center;">24</td>
+<td style="text-align: center;">GND</td>
+<td style="text-align: center;">GND</td>
+<td style="text-align: left;">Ground</td>
+</tr>
+<tr class="odd">
+<td style="text-align: center;">25</td>
+<td style="text-align: center;">PC_RXD1</td>
+<td style="text-align: center;">RBUS_RX</td>
+<td style="text-align: left;">MIDI receive <a id="n5" href="#note5" class="note">[5]</a></td>
+</tr>
+</tbody>
+</table>
+<h2 id="tocanch3" class="tvis">Official cable wiring</h2>
+<p>Roland has only disclosed partial information on the wiring scheme
+used by the official R-BUS cables. <a id="n6" href="#note6" class="note">[6]</a>
+However, it’s rather easy to infer the full wiring scheme from that
+information. This has been confirmed by other third-party sources.
+<a id="n7" href="#note7" class="note">[7]</a> <a id="n8" href="#note8" class="note">[8]</a></p>
+<table>
+<colgroup>
+<col style="width: 25%">
+<col style="width: 18%">
+<col style="width: 11%">
+<col style="width: 18%">
+<col style="width: 25%">
+</colgroup>
+<thead>
+<tr class="header">
+<th style="text-align: right;">Usage 🖙</th>
+<th style="text-align: center;">Pin on one side</th>
+<th style="text-align: center;">is connected to</th>
+<th style="text-align: center;">Pin on the other side</th>
+<th style="text-align: left;">🖘 Usage</th>
+</tr>
+</thead>
+<tbody>
+<tr class="odd">
+<td style="text-align: right;">+5V</td>
+<td style="text-align: center;">1</td>
+<td style="text-align: center;"></td>
+<td style="text-align: center;">13</td>
+<td style="text-align: left;">+5V In</td>
+</tr>
+<tr class="even">
+<td style="text-align: right;">SDOUT1</td>
+<td style="text-align: center;">2</td>
+<td style="text-align: center;"></td>
+<td style="text-align: center;">12</td>
+<td style="text-align: left;">SDIN1</td>
+</tr>
+<tr class="odd">
+<td style="text-align: right;">SDOUT2</td>
+<td style="text-align: center;">3</td>
+<td style="text-align: center;"></td>
+<td style="text-align: center;">11</td>
+<td style="text-align: left;">SDIN2</td>
+</tr>
+<tr class="even">
+<td style="text-align: right;">SDOUT3</td>
+<td style="text-align: center;">4</td>
+<td style="text-align: center;"></td>
+<td style="text-align: center;">10</td>
+<td style="text-align: left;">SDIN3</td>
+</tr>
+<tr class="odd">
+<td style="text-align: right;">GND</td>
+<td style="text-align: center;">5</td>
+<td style="text-align: center;"></td>
+<td style="text-align: center;">9</td>
+<td style="text-align: left;">GND</td>
+</tr>
+<tr class="even">
+<td style="text-align: right;">SDOUT4</td>
+<td style="text-align: center;">6</td>
+<td style="text-align: center;"></td>
+<td style="text-align: center;">8</td>
+<td style="text-align: left;">SDIN4</td>
+</tr>
+<tr class="odd">
+<td style="text-align: right;">NC</td>
+<td style="text-align: center;">7</td>
+<td style="text-align: center;"></td>
+<td style="text-align: center;">7</td>
+<td style="text-align: left;">NC</td>
+</tr>
+<tr class="even">
+<td style="text-align: right;">SDIN4</td>
+<td style="text-align: center;">8</td>
+<td style="text-align: center;"></td>
+<td style="text-align: center;">6</td>
+<td style="text-align: left;">SDOUT4</td>
+</tr>
+<tr class="odd">
+<td style="text-align: right;">GND</td>
+<td style="text-align: center;">9</td>
+<td style="text-align: center;"></td>
+<td style="text-align: center;">5</td>
+<td style="text-align: left;">GND</td>
+</tr>
+<tr class="even">
+<td style="text-align: right;">SDIN3</td>
+<td style="text-align: center;">10</td>
+<td style="text-align: center;"></td>
+<td style="text-align: center;">4</td>
+<td style="text-align: left;">SDOUT3</td>
+</tr>
+<tr class="odd">
+<td style="text-align: right;">SDIN2</td>
+<td style="text-align: center;">11</td>
+<td style="text-align: center;"></td>
+<td style="text-align: center;">3</td>
+<td style="text-align: left;">SDOUT2</td>
+</tr>
+<tr class="even">
+<td style="text-align: right;">SDIN1</td>
+<td style="text-align: center;">12</td>
+<td style="text-align: center;"></td>
+<td style="text-align: center;">2</td>
+<td style="text-align: left;">SDIN1</td>
+</tr>
+<tr class="odd">
+<td style="text-align: right;">+5V In</td>
+<td style="text-align: center;">13</td>
+<td style="text-align: center;"></td>
+<td style="text-align: center;">1</td>
+<td style="text-align: left;">+5V</td>
+</tr>
+<tr class="even">
+<td style="text-align: right;">MIDI TX</td>
+<td style="text-align: center;">14</td>
+<td style="text-align: center;"></td>
+<td style="text-align: center;">25</td>
+<td style="text-align: left;">MIDI RX</td>
+</tr>
+<tr class="odd">
+<td style="text-align: right;">GND</td>
+<td style="text-align: center;">15</td>
+<td style="text-align: center;"></td>
+<td style="text-align: center;">24</td>
+<td style="text-align: left;">GND</td>
+</tr>
+<tr class="even">
+<td style="text-align: right;">GND</td>
+<td style="text-align: center;">16</td>
+<td style="text-align: center;"></td>
+<td style="text-align: center;">23</td>
+<td style="text-align: left;">GND</td>
+</tr>
+<tr class="odd">
+<td style="text-align: right;">GND</td>
+<td style="text-align: center;">17</td>
+<td style="text-align: center;"></td>
+<td style="text-align: center;">22</td>
+<td style="text-align: left;">GND</td>
+</tr>
+<tr class="even">
+<td style="text-align: right;">FS Out</td>
+<td style="text-align: center;">18</td>
+<td style="text-align: center;"></td>
+<td style="text-align: center;">21</td>
+<td style="text-align: left;">FS In</td>
+</tr>
+<tr class="odd">
+<td style="text-align: right;">GND</td>
+<td style="text-align: center;">19</td>
+<td style="text-align: center;"></td>
+<td style="text-align: center;">20</td>
+<td style="text-align: left;">GND</td>
+</tr>
+<tr class="even">
+<td style="text-align: right;">GND</td>
+<td style="text-align: center;">20</td>
+<td style="text-align: center;"></td>
+<td style="text-align: center;">19</td>
+<td style="text-align: left;">GND</td>
+</tr>
+<tr class="odd">
+<td style="text-align: right;">FS In</td>
+<td style="text-align: center;">21</td>
+<td style="text-align: center;"></td>
+<td style="text-align: center;">18</td>
+<td style="text-align: left;">FS Out</td>
+</tr>
+<tr class="even">
+<td style="text-align: right;">GND</td>
+<td style="text-align: center;">22</td>
+<td style="text-align: center;"></td>
+<td style="text-align: center;">17</td>
+<td style="text-align: left;">GND</td>
+</tr>
+<tr class="odd">
+<td style="text-align: right;">GND</td>
+<td style="text-align: center;">23</td>
+<td style="text-align: center;"></td>
+<td style="text-align: center;">16</td>
+<td style="text-align: left;">GND</td>
+</tr>
+<tr class="even">
+<td style="text-align: right;">GND</td>
+<td style="text-align: center;">24</td>
+<td style="text-align: center;"></td>
+<td style="text-align: center;">15</td>
+<td style="text-align: left;">GND</td>
+</tr>
+<tr class="odd">
+<td style="text-align: right;">MIDI RX</td>
+<td style="text-align: center;">25</td>
+<td style="text-align: center;"></td>
+<td style="text-align: center;">14</td>
+<td style="text-align: left;">MIDI TX</td>
+</tr>
+</tbody>
+</table>
+<h2 id="tocanch4" class="tvis">Electrical
+characteristics of the interface</h2>
+<h3 id="tocanch5" class="tvis">Power</h3>
+<p>The +5V supply is derived straight from the +5V rail that goes into
+the main board, with polarity protection (both in the XV-5080 and
+VS-2400) provided with a Schottky diode, and sometimes a current
+protected with a thermistor (not present in the XV-5080).</p>
+<p>The +5V pin measured 5.28V to ground on my XV-5080.</p>
+<h3 id="tocanch6" class="tvis">Digital Audio</h3>
+<p>The format of digital audio portion of R-BUS resembles <a href="https://en.wikipedia.org/wiki/I%C2%B2S">I²S</a>, but with a few
+key differences:</p>
+<ul>
+<li>There’s no bit clock.</li>
+<li>Sample data are transmitted as if they are 32-bit, despite only the
+first 24-bit is being used.</li>
+<li>Logic level on the data line is inverted.</li>
+</ul>
+<p>To give a standalone description of the R-BUS digital audio
+protocol:</p>
+<ul>
+<li>The frame sync (word clock) signal runs at the same frequency as the
+sampling rate.</li>
+<li>When frame sync is low, left channel of each channel pair is being
+transmitted, otherwise right channel is being transmitted.</li>
+<li>Each half cycle of the frame sync clock is divided into 32 periods,
+during each of which a bit of sample data is sent on every serial data
+line.</li>
+<li>Sample data are sent most significant bit (MSB) first. Each sample
+is 24-bit long, leaving 8 bits unused at the end of each half cycle of
+frame sync.</li>
+<li>Logic low on the data line means the bit being sent is 1, and high
+means it’s a 0.</li>
+</ul>
+<p>If you’d like a timing diagram of all this, please look up the
+datasheet of TC9271 made by Toshiba (used in the XV-5080 as its S/PDIF
+encoder chip). Figure 1b is a good representation of the relationship
+between frame sync (LRCK in the datasheet) and audio data. The LRS=H
+case in figure 3a shows how the frame sync signal sent over R-BUS should
+be interpreted.</p>
+<p>There are 4 serial data lines in each direction, giving the 8
+channels in total for each direction. Each direction has its own frame
+sync signal, which is shared among all data lines in that direction.</p>
+<h3 id="tocanch7" class="tvis">MIDI</h3>
+<p>What is sent over the MIDI wires in the R-BUS cable has not been
+confirmed by me.</p>
+<p>The MIDI interface is used differently on different Roland
+products:</p>
+<ul>
+<li>XV-5080 seem to ignore everything on the R-BUS MIDI interface,
+despite having all the facilities to handle it. Roland disclosed this in
+RPC-1’s user manual (see the section on XV-5080). I have not tested this
+claim.</li>
+<li>MV-8000 series with MV8-OP1 installed can use the R-BUS MIDI output
+as a separate MIDI port. Data going into the R-BUS MIDI port will be
+mixed with the built-in MIDI input.</li>
+<li>VM-3100Pro can pass through the MIDI data to its built-in MIDI
+ports, and can control the host sequencer if connected to a
+computer.</li>
+<li>V-Studio products can receive MIDI clock over R-BUS.</li>
+<li>Any aspects / products not mentioned here are unknown to me.</li>
+</ul>
+<p>Roland calls the signals that go in to / out of these pins “IPC” or
+“PC”. <a id="n9" href="#note9" class="note">[9]</a></p>
+<p>Inside both the VS-2400 and the XV-5080, the signal is generated /
+goes into a dedicated microcontroller (a M3888 1M2), specifically, a
+pair of its UART ports. An inverter is between the R-BUS connector and
+the MCU in each direction of the signal.</p>
+<p>Roland claims in VS-2480’s manual that R-BUS carries 8 channels of
+bidirectional digital audio (which are already fully accounted for in
+the previous section), plus MIDI, MMC (MIDI Machine Control) and MTC
+(MIDI Timecode).</p>
+<p>The factual portion of this section ends here. Everything below is my
+guesswork. Since MMC commands and MTC are both usually just sent as
+normal MIDI messages, it’s a reasonable assumption that, the only thing
+that is transmitted over these wires is MIDI, which is also why I named
+them MIDI TX/RX in my pin usage chart.</p>
+<p>Since MIDI is pretty much just UART with a bit of isolation, I would
+venture a guess that the signal sent / expected on these two pins is
+just inverted MIDI UART signal.</p>
+<p>It would be pretty trivial to build some experimental circuitry to
+test my theory. Maybe I’ll do it one day. However this may end up with
+nothing – as the XV-5080 will probably just ignore the MIDI data going
+through R-BUS.</p>
+</article>
+</div><br><hr>
+		<div class="TText" id="notediv" style="font-size:80%;"><span class="TText"><a id="note1" href="#n1">[1]</a>: Serial data
+output (input). Overline indicates that 1-bit is represented with low
+logic level and 0-bit with high logic level. Same
+below.<br></span><span class="TText"><a id="note2" href="#n2">[2]</a>: Not connected. Same
+below.<br></span><span class="TText"><a id="note3" href="#n3">[3]</a>: Inferred from wiring scheme<br></span><span class="TText"><a id="note4" href="#n4">[4]</a>: Often abbreviated
+as TX.<br></span><span class="TText"><a id="note5" href="#n5">[5]</a>: Often abbreviated
+as RX.<br></span><span class="TText"><a id="note6" href="#n6">[6]</a>: <a href="https://support.roland.com/hc/en-us/articles/201978779-R-BUS-RBUS-RBC-RBC-5-Where-Can-I-Find-an-R-BUS-Cable">R-BUS,
+RBUS, RBC, RBC-5: Where Can I Find an R-BUS Cable?</a><br></span><span class="TText"><a id="note7" href="#n7">[7]</a>: <a href="https://web.archive.org/web/20240204170917/https://www.vsplanet.com/ubbthreads/ubbthreads.php?ubb=showflat&amp;Number=450346">Roll
+your own: R-Bus Cable Pin Out.</a><br></span><span class="TText"><a id="note8" href="#n8">[8]</a>: <a href="https://web.archive.org/web/20211204221550/https://themidimaniac.com/diy-r-bus-cable-for-20e/">DIY
+R-BUS cable for 20€</a><br></span><span class="TText"><a id="note9" href="#n9">[9]</a>:  I have no idea what these could mean. My
+software-dominated brain tells me they stand for “Inter-Process
+Communication” and “Program Counter” but they clearly stand for
+something else here.<br></span></div>
+		<div id="insanch" style="height:3em;"></div>
+		<div id="footer" style="">
+		<div id="pagesw" class="TText" style="width:100%;height:0.5em;"></div>
+			<div style="text-align:center;" class="TText">
+				Proudly powered by SSBS <reduced style="font-size:70%;">(the static stupid blogging system)</reduced> 2.5
+				<br>
+				Content licensed under CC BY-SA 4.0. <span id="purgep" style="display:none;font-size:70%;">This page has passphrase(s) stored. Click <a href="javascript:_purgep()">here</a> to purge.</span>
+			</div>
+		</div>
+		<div id="cmdbuf" class="TText" style="transition:500ms;padding:1em;font-size:2em;color:white;position:absolute;background-color:rgba(0,0,0,0.6);left:50%;top:50%;transform:translate(-50%,-50%);pointer-events:none;opacity:0;">
+		</div>
+	</div>
+	<div id="decryptui" style="display:none;opacity:0;color:white;z-index:1000;position:fixed;left:0;top:0;width:100%;height:100%;background-color:rgba(0,0,0,0.4);transition:opacity 0.5s;">
+		<div id="decryptdlg" class="TText" style="padding:10px 20px;position:absolute;left:50%;top:50%;transform:translate(-50%,-50%);background-color:rgba(0,0,0,0.6);">
+			<div id="keyhint" style="margin-bottom:8px;"></div>
+			<div style="margin-bottom:8px;">Key: <input id="keyinp" type="text" style="color:#fff;"></div>
+			<div style="height:2.25em;">
+			<button id="btndecrypt" onclick="decryptor(decid,document.getElementById('keyinp').value);" style="position:absolute;left:20px;">Decrypt</button>
+			<button onclick="hidedecryptui();" style="position:absolute;right:20px;">Cancel</button>
+			</div>
+		
+	</div>
+
+
+</div></body></html>
+\ No newline at end of file
author	Chris Xiong <chirs241097@gmail.com>	2024-02-17 20:44:52 -0500
committer	Chris Xiong <chirs241097@gmail.com>	2024-02-17 20:44:52 -0500
commit	891f8eee12e6bdb2fad0fe0b28976362eb965236 (patch)
tree	8a78ffa14ecf3c8893fbfd441cf50b1978ee33cd /blog/post/2024-02-02.html
parent	d5e40e5890cd99144a44e2922fd97ddaa9968c14 (diff)
download	web-891f8eee12e6bdb2fad0fe0b28976362eb965236.tar.xz