Jay,
Couple of points that may help you.
1) A serial port does not have data ports 0-n. A serial port takes a
byte (8 bits), then shifts them down a single pipe using a chip called a
UART (feel free to google for unfamiliar terms).
example
Bit pattern 1010 1010
would be shifted one bit at a time
1
0
1
0
1
0
1
0
a one is +5 volts on single send line of the UART and 0 is 0 volts.
RS232 uses a different mapping for 1's and 0's (but is still serial)
1 - ~-3V - -12 V
0 0-12 V
So you slap a chip on between the UART and the RS232 pin (usually a
MAX232) that translates the voltages for you.
On the other end of the wire
232 socket
MAC232
UART (usually built into the microcontroller)
Register in Microcontroller
I like playing at this level. I would recommend using AVR
microcontroller (easiest to program and there is an open source
gcc compiler).
for $20.00 US you can buy the butterfly eval board with:
- microcontroller
- max232 all wired up for rs232 connection from your computer
- lcd display
- temperature sensor
- light sensor
- the avr mega169 has many goodies
- analog - digital converter
- digital -> analog converter
- LCD controller
This is a great bargin.
If you are starting out in microcontrollers. I would suggest that you
go to:
http://smileymicros.com/
They sell a nice package for $90.00
- butterfly eval board
- great, easy to follow book on how to develop on microcontrollers for
the beginer.
- project kit - includes everything you need to build all of the
projects (even includes the wire ;-)
There are python libs that support Ateml Avr connections:
It is easy to use your rs232 serial with a microcontroller at the other
end of the wire. Microcontrollers are cheap. If you fry why is
connected to your devices, you are only out the microcontroller.
Have fun,
Mike
[EMAIL PROTECTED] wrote:
> I want to write to the pins of an RS232 without using the serial
> protocol. The use would be every pin could act to complete a circuit
> in customized hardware. I could use python to communicate serially to
> a BASIC stamp or a Javelin stamp and then use the stamp to set however
> many pins as 0's or 1's but should it be that hard to do with python.
> I've looked through how python does serial with the "serial" module but
> it just uses Java's javax.comm libraries. Is there anyway to do very
> low level device writing to COM ports?
>
> In summary I'm looking for something like:
> ser = serial.Serial(0)
> ser.pin0 = 1
> ser.pin1 = 1
> ser.pin2 = 1
> ....
>
>
> or
> ser.write('0xFF')
> which would set 8 pins on the RS232 cable to 1's
>
--
The greatest performance improvement occurs on the transition of from
the non-working state to the working state.
--
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