Yamaha DB50XG Bedienungsanleitung PDF herunterladen

mistralXG – a USB connected, PIC-based MIDI synthesizer

Part I

Introduction

mistralXG is a MIDI synthesizer, based on a MIDI daughter card such as the Yamaha

DB50XG. It could also be used as a USB MIDI switching and monitoring device without the

daughtercard.

In this first of two articles, I’ll explain how mistralXG operates and discuss the main

technologies it uses. The second article will look at the hardware and software in more detail.

Parts cost for the project is $20 to $30, excluding the daughter card, power supply and

enclosure.

Choosing a project

A couple of my earlier projects were based on the PIC12C508A, one of the least powerful

Microchip PIC microcontrollers (MCUs). Developing them was great fun and provided my

first experience of these fantastic little devices. For my next project, I wanted to use a more

powerful MCU and utilize some of the wide range of on-chip peripherals.

I've dabbled in MIDI for many years and, as my current PC’s sound card hasn't got the

necessary WaveBlaster-compatible connector, had an unused Yamaha DB50XG synthesizer

daughter card. The Internet revealed some designs that use the DB50XG as a stand-alone

synthesizer, but that just feed MIDI data to the card. I wanted something a little more

capable, to allow me to play my MIDI wind controller away from my computer. This was an

ideal area for my project.

In August 2005, N&V had published Robert Lang's Midi-nator design, which showed that a

hobbyist could create a USB-based MIDI device. But, rather than use Midi-nator as a starting

point, I wanted to create a complete new MIDI implementation so that I knew exactly what

the device was and wasn't capable of.

Start at the beginning

Late in 2007, I began thinking about the design. I burned the MIDI-nator project code into a

PIC18F2550 to see it in action and, while it worked well, it was evident that there was a steep

learning curve to designing with USB. Thankfully, there is plenty of information available

(see references). Microchip also provides comprehensive datasheets – the PIC18F2550

document runs to 430 pages – so I had a lot of reading to do. A few months later, after

sketching out some different approaches, I started serious work on the design.

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Inhaltsverzeichnis

Seite 1 - Start at the beginning

mistralXG – a USB connected, PIC-based MIDI synthesizer Part I Introduction mistralXG is a MIDI synthesizer, based on a MIDI daughter card such as the

Seite 2 - Technology overview

mistralXGUSB interfaceto PCSwitch 2Switch 1MIDI INWX INMIDI OUTMIDI THRUDB50XGSynthesizerDaughter cardHeadphone& Line OutMicrochipPIC18F2550Extern

Seite 3

A command might say, "Play Middle C on channel 5, medium loud". Three bytes are required to construct this command. These are (in hexadecima

Seite 4 - Putting it all together

other things. When enumeration completes successfully, the device becomes available to the system. Suitable USB MIDI drivers are provided with both Wi

Seite 5

Figure 2. mistralXG prototype At front left, you can see the DB50XG, with the LCD to the right. The PIC18F2550 is the large chip to center-right of t

Seite 6 - Using mistralXG

The Home Screen displays: • USB status: the “cactus”, six characters from the end of the first row, is my lo-res attempt at the USB symbol. It is dis

Seite 7 - Error flags and counters

User options The first two screens allow you to select which MIDI stream is transmitted to the synthesizer. The first option flag on the Home Screen (

Seite 8 - Next time: Technical details

Here’s a quick summary of the error types. More detailed information is in the source code: BFO These flags indicate errors receiving MIDI data from

Seite 9 - Resources:

Resources: Here are a few links that I have found useful. Links come and go of course – if that happens, just load a few key words into your favorite