Simple Midi Controller

[Mikko Helin]

PIC 16F84 (newer version of 16C84 with 64 bytes of RAM) is indeed nice,
and the programmer for it is easy to build also. But for
MIDI kbd, pitch bend and controller input you don't want to use
it to emulate UART (there's no inbuilt so you got to do
it with timing loops). It's better to use external UART like
MAX3100, which has serial interface (good for PICs, as they don't
have too many input/output ports). Maxim has also many 8-channel
ADC's (10-16 bit) with serial output available, as well as DAC's which you
could use for CV generation for analog synths.

Another good choice for microcontroller could be Atmel's 89S2051,
which has inbuilt UART, and is Intel 8051 compatible (without
external data bus interface), 20-pin device (PIC is 18 pin).
I have an extra (musical) keyboard without MIDI, and one future
project is to midify it using AT89S2051.

Now, if somebody has reached this line before pressing delete button,
I'd like to introduce him/her the Scenix SX-18/SX-28 PIC16C5x compatible
(almost) processors with upto 100 Mhz/ 100 MIPS operation and
low price (around $5 or litle bit more). See www.scenix.com,
they even specially mention in datasheets that these devices 
could be used in musical synthesis applications!


-Mikko



>Does anyone have a schematic for a simple midi controller? I will need

>parameters for 4 octaves of kbd control, pitch bend, modulation,and

>midi channel assign. Thanks in advance. Lew =20

I designed something similar to what you want. I have the scematic somewh=
ere
for it. It is based around a PIC16C84, so you need access to a programmer=
 (I
built mine for =A32 :-) ) but that allows you to make changes to the prog=
ramme
as the evice evolves! A PIC is the easiest way of doing it, as otherwise =
you
have to make logic to genarate the timing and the serial messages. The
timing has quite a large window, as it is wondow based!, but it would
require a LOT of logic. As you want pitch bant and modulation, it would
probably be best to design it around a PIC16C74, as this has eight A/D
converters built in that you could use for the analogue input. It also ha=
s
an onboard UART, which you could configure for MIDI communication. Whilsh
only having 33 I/O lines, you could multiplex the keyboard to allow fot t=
he
four octaves.

Hope this helps,
James.
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James Jackson - A Minefield Of Information

Who ever knew a 14 year old could program and make
electronic stuff??
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