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Subject: Hardware thoughts

From: Eric Brombaugh <ebrombaugh@...>
Date: 2006-03-08

What's the hardware architecture going to be? I
haven't ever seen a PSIM up close, but here's what I
think is baseline:

∗ BasicATOM Pro 28-M
http://www.basicmicro.com/Product.aspx?productID=151&CategoryID=2
- Up to 8 channels 10-bit Analog inputs
- Serial digital I/O
- parallel digital I/O.
All shared on 20 GPIO pins.

∗ 4-channels serially loaded DAC.
What brand of DAC was used on the PSIM?
2 Dual DACs or one Quad DAC?
Separate or simultaneous load strobe?
How many bits?

∗ Analog Signal conditioning.
- Input gain & offset pots or fixed?
- Output gain & offset pots or fixed?
- Lowpass filtering?

∗ Serial I/O
- BasicATOM Pro uses built-in UART on H8/3664
processor for firmware loads.
- Need to re-task serial I/O for MIDI interfaces
- Front panel switch to select MIDI mode?
Do we want a built in USB-Serial interface?
- Many (most?) modern PCs now come without RS-232
interfaces, but a USB-Serial chip is fairly cheap
and readily available. See the SiLabs CP210x:
http://www.silabs.com/tgwWebApp/public/web_content/products/Microcontrollers/Interface/en/interface.htm


∗ Digital I/O
- Digital I/O is somewhat scarce on the 28-pin
BasicATOM Pro. Use 74HC595 serial-parallel for
dedicated outputs, or Maxim MAX6957 port extender
for flexible I/O over SPI.

∗ LCD
- 2x16 char LCD w/ backlight seems a fairly useful
& common mod. Use Serial I/O with
external processor, or hook up parallel via SPI
port extender (see above).

∗ Buttons
- Used for run/stop/etc.
- Use dedicated GPIO pins on BasicATOM Pro, or
hook up via SPI port extender using available
interrupt line.

Just a collection of thoughts about hardware. Comments
& criticism invited.

Eric


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