piclist 2000\05\26\182255a >
Thread: Microcontroller with 4 USARTs and 40 pins
face BY : Edson Brusque email (remove spam text)

> Perhaps if you give us a little more information we can help you out more.

   As I'm a musician, and my (piano) keyboard controller doesn't makes all
the tricks I would like it to do, I'm thinking in developing a MIDI
black-box that could do everything I want. Maybe I can sell hundreds of
units and make some money :)

> It is unlikely that you will find an 8-bit micro with 4 hardware UARTs (as
> hobbyist), so you probably should plan on finding one with one or two
UARTs and
> build the rest in software.  If I were in your shoes, I would build them
all in
> software.  If you run a scenix or atmel at 24 MIPs, you'll have exactly
> instructions (scenix, varies for atmel) per bit time to run the UARTs and
> user process (at the specified 31.25Kbps).  Divide it by four (bit
slicing) and
> you end up with 192 instructions to read the state of four RX lines,
change the
> state of four TX lines, and then do some data processing.  It really would
> be too difficult.

   I think I'll want to put 16 keys on the thing (8 I/Os for that), an LCD
(6 I/Os for that), four MIDI Ins plus four midi Outs (8 I/Os), and I would
like it to communicate with the PC with Paralell or USB. Even Serial at
115.200bps would do the job nicely. Well, this puts 22 I/Os plus PC
communication. A 48 or 52 pin Scenix at 50MHz seens to be a very good option
(I've took a look at SX documentation and it says it can run eight 19.2Kbps
UARTs using 13% of 50MHz). The hard thing will be to make an adaptor to use
it on a proto-board.

   I would also like to put 16 pots on it to control various things (like
volume, pan, reverb, modulation, etc).

   I would preffer to make it with PICs, but I don't think it's possible. I
don't want to expend money on another C compiler, debugger, etc...

   Atmel would also be a good option. What Atmel micros can do 24MIPS?

   Best regards,


<006401bfc761$59741c40$41a0f7c8@bigbru> 7bit

See also: www.piclist.com/techref/io/serials.htm?key=usart
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