[futurebasic] [FB] Re: Analog Thru the USB Port

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From: Walter Lenk <Walter_Lenk@...>
Date: Mon, 3 May 2004 17:46:25 -0400
Greetings -

On April 30, 2004, Scott Spencer wrote:
>  I for one would like to know more about what you're doing...

On 30 Apr 2004 Robert Covington wrote:
>  I am quite interested too, because I've tried to run some PIC
>  Programming things via Virtual PC (2.0) on my Umax, and also Windows
>  machine (cheapie P2 266), with various programmers. Not much luck yet,
>  just getting the programming setups to work is very windows-ish and
>  unreliable for me so far, and I can't get such to work in the Windows
>  console when in Virtual PC. (Dos'y things)

Sorry for the delay - I get the list in digest mode, and they come 
out every several days now rather then daily. I sent the following to 
Scott privately, but I'll post it for the group:

The short answer is that I am by vocation an electrical engineer - 
self employed, and specializing mostly in audio, process control, and 
data gathering.  Over the last 15 years or so, I have found that many 
of my projects have migrated from pure hardware to a combination of 
hardware and software - many of these projects use a PIC 
microprocessor (with the firmware written in assembly) to control the 
process or gather the data, which then often talks to a FB program 
over the serial port for overall control and display. Some of these 
projects are mundane, some of them are wild and whacky, and some of 
them are a result of my personal whimsey. Here is a sample:
   An medical ADHD evaluation test using an infrared motion sensing camera
   Data gathering devices for High School Science curriculum
   Process and sequence control for several kinetic sculptures
   Data gathering (including vital signs) for a drug evaluation study
   A home temperature setback thermostat
   A home X10 automation control timer
   Audio test equipment - including a frequency response grapier.
   A home heating system data logger (what's on, and for how long)
   Several school playground devices; including a light Track, where a sequence
     of lights (30 or so that are a meter apart) pace runners.

The longer answer depends on what part of all this you might be interested in.

>  Have you looked at Drek's USB stuff on the FB3 CD??

Briefly, but I haven't found it all that useful so far. There are 
several reasons for this:
1. The PICs that I use have a hardware USART in them that is 
straightforward to use, and implementing a USB port would require 
considerably more horsepower than the actual task itself currently 
uses.
2. My data transmission requirements are usually far below the limit 
of a 9600 baud serial port.
3. The remade external devices that I sometimes work with have always 
been serial port rather than USB.
4. The Keyspan adapters and their drivers work well, and the FB OSX 
serial port code also works well.
5. I can see serial port chatter with my scope and decipher it to some degree.

I realize that USB is the coming thing, but it is _WAY_ more complex 
than the old legacy serial port. At some time however, I will 
probably be dragged kicking and screaming into the future.

As to Robert's question about PIC development on the MAC:
  1. I write the source code in BBEdit under OSX.
  2. I assemble the source code with the Tech-Tools 'CVASM16.EXE' 
assembler, running in the DOS part of Windows 98 that runs under 
Virtual PC 6.1 under OS 10.3 on my 800 MHz iMac. The source code is 
in a folder that is recognized as a network disk by virtual PC. The 
object code file is left in this same folder.
  3. The object code is loaded into the target PIC thru a Tech tools 
'Picwriter' that is connected to the MAC via a Keyspan USA28X USB to 
dual serial port adapter. The Tech tools 'Picwriter' software runs 
under Windows 98 that runs under Virtual PC 6.1. About 19+ times out 
of 20 this works well - once in a while I have to reset things.

I used to do steps 2 & 3 with an old Wintel Laptop via the 'floppy 
shuffle' (what a pain), but about a year ago I figured out how to do 
it all on the MAC. I am certainly not a Microsoft fan, but I must say 
that one of the neat things about Virtual PC (now owned by 
Microsoft!) is the ability to save the state of the virtual machine. 
This takes about 5 or 10 Seconds to do, and then when next you run 
Virtual PC again (maybe days later), your whole Windows environment 
comes up in about 5 or 10 Seconds just as you last left it - programs 
running, files open, etc. I'm impressed.

Robert, if you (or anyone else) want more PIC development details, 
I'd be happy to oblige - in some ways talking on the phone may be an 
easier back and forth, so don't hesitate to call.

Cheers,

Walter

-- 
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Walter Lenk    Cambridge Ma    617-547-7781
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