Jasper JasperMIDI Manual

Table of Contents

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Building and using JasperMIDI

Introduction........................................................................................................................................... 1

Bill Of Materials..................................................................................................................................... 2

Building Choices................................................................................................................................... 3

Construction.......................................................................................................................................... 4

Installing in a Jasper enclosure............................................................................................................. 5

Standalone use..................................................................................................................................... 6

Using JasperMIDI................................................................................................................................. 7

PCB Size and layout............................................................................................................................. 8

Advanced - updating and hacking JasperMIDI.....................................................................................8

The Link Bus......................................................................................................................................... 9

Mapping Link to MIDI............................................................................................................................ 9

Introduction

JasperMIDI is a simple MIDI interface to allow you to

connect Jasper or other EDP link enabled equipment

like the vintage Wasp and Gnat Synths or Spider

sequencer to modern control equipment.

It can be used installed in an enclosure of a Jasper

synth, connected directly to the main PCB, or stand

alone in an external box. JasperMIDI has an optional

5V regulator allowing it to be powered with a 6V - 12V

supply, or this can be left out and it can be powered

using an existing regulated 5V. It can also take power

over the Jasper mini DIN connector.

JasperMIDI is based around an ATMega328P

processor programmed using the Arduino environment. The MIDI input is protected using a 6n137

opto-isolator. Spare analogue and digital ports are broken out, allowing for optional expansion or

additional features to be implemented.

The Link bus is quite a limited control method - Wasp type synthesisers only have 3 octaves of

control, purely monophonic. All devices on the same link bus will play or respond to the same note

at the same time.

JasperMIDI guide

Page 1 of 9

November 2017

Table of Contents

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Summary of Contents for Jasper JasperMIDI

Page 1: Table Of Contents
The Link Bus............................9 Mapping Link to MIDI..........................9 Introduction JasperMIDI is a simple MIDI interface to allow you to connect Jasper or other EDP link enabled equipment like the vintage Wasp and Gnat Synths or Spider sequencer to modern control equipment.
Page 2: Bill Of Materials
JasperMIDI guide Bill Of Materials There are no rare or expensive components in JasperMIDI. All the items can be obtained from the usual electronics components suppliers. No special tools are required to build JasperMIDI – just the usual soldering iron, solder and side cutters. If you wish to program the ATMega328 yourself, then you will need an AVR compatible ISP programmer like the USBtinyISP.
Page 3: Building Choices
If you only want MIDI input, then you can omit one of the 5 pin DIN sockets. • If you are happy with only having JasperMIDI operate on MIDI channel 1, you can omit the • pushbutton switch.
Page 4: Construction
MIDI channel number. It is MIDI channel 1 by default, so leave the push-button out if you are happy with this and don’t anticipate changing it. MIDI DIN Socket wiring: cut your wire long enough to reach from the JasperMIDI PCB headers to where the sockets are located in your enclosure.
Page 5: Installing In A Jasper Enclosure
JasperMIDI guide Installing in a Jasper enclosure If you built Jasper with a case including a speaker, then there will be enough room to install JasperMIDI. You can omit soldering the mini-din socket, and the power regulator components. Use hookup wire or ribbon cable to connect JasperMIDI to the Jasper main board. Use the 5V header on the JasperMIDI PCB to the 5V pads (or connector) on the Link2 header.
Page 6: Standalone Use
Standalone use It is possible to put JasperMIDI in an external box – it can be powered by a Jasper using the mini- DIN cable. If you wanted to make an external enclosure for use with the vintage Link equipment, then it can be powered by battery, or external DC.
Page 7: Using Jaspermidi
MIDI connectors – you may damage things. JasperMIDI has a current draw of around 20mA to 23mA in use. If it is idle for a period of time, the microcontroller goes to sleep drawing less than 8mA. Activity on the Link or MIDI input ports or a press of the button will wake it up.
Page 8: Pcb Size And Layout
The Arduino analogue pins A0 to A4 are broken out for further expansion. In the original firmware written for JasperMIDI, A0 is used for a push-button that is used to set the MIDI channel. Also A4 is used for a debug serial port, if a flag is set in the source.
Page 9: The Link Bus
Input mode with any internal pull-up resistors switched off. The Wasp/Jasper keyboard allows playing of the top two octaves, but by using the Link port another octave is possible, shown in grey above. There is a hardware ‘bug’ in the Wasp/Jasper decoding circuitry –...