L
[email protected]
- Jan 1, 1970
- 0
Hello All, I have a serious problem getting my circuit to work, and
maybe someone here can help. I read threads here all the time, and
have gotten some help one or twice (who knows, maybe someday ill be
able to give advice).
Anyway, I'm trying to interface a simple circuit to my PC's
parallel port such that I can read 8-bits of data from an ADC. I have
several ADC0820's (http://cache.national.com/ds/DC/ADC0820.pdf) lying
around so I am going to try to use them. My current circuit is as
follows:
Pin 1: Vin
Pin 2: Pin 2 of Parallel Port
Pin 3: Pin 3 of Parallel Port
Pin 4: Pin 4 of Parallel Port
Pin 5: Pin 5 of Parallel Port
Pin 6: Pin 1 of Parallel Port
Pin 7: +5 volts
Pin 8: Ground
Pin 9: Not Connected
Pin 10: Ground
Pin 11: Ground
Pin 12: +5 volts
Pin 13: Ground
Pin 14: Pin 6 of Parallel Port
Pin 15: Pin 7 of Parallel Port
Pin 16: Pin 8 of Parallel Port
Pin 17: Pin 9 of Parallel Port
Pin 18: Not Connected
Pin 19: Not Connected
Pin 20: +5 volts
Note that I am not using resistors neither between my ADC and parallel
port nor between Vin and my ADC. Also note, Vin does not exceed +5
volts.
I currently have a small program (Visual Studio .NET) to see if my
circuit is working. Note that I am using Inpout32.dll
(http://www.logix4u.net/inpout32.htm) to access the parallel port.
What I would is when I touch a wire lead from Vin to +5 volts to see
255 printed to my computer monitor, and when I touch the wire to ground
to see 0 on the screen. What I DO see is 189 or 188 printed to the
screen when I touch the wire to +5 volts and 3 or 4 when I touch the
lead to ground. I am very confused
My (pseudo) Code:
Out(890,32); //Turn on "Bi-Directional" mode and set pin 1 (pin 6
of ADC0820) high.
while(1)
{
Out(890,33); //Set pin 1 (pin 6 of ADC0820) low while
keeping bit 5 high.
Out(890, 32); // Set pin 1 (pin 6 of ADC0820) high again.
printf("%d\n", In(888) );
}
END OF CODE
Note pin 1 of parallel port is inverted so a 1 sets the pin to low.
Parallel Port Reference: http://www.logix4u.net/parallelport1.htm
What ISN'T wrong. My parallel port is ECP mode and DOES support
bi-directional functionality, the ACD0820 chip is in working condition,
and my parallel port is in working condition. Anyway, I hope someone
has some experience with these issues and could give me some advice. I
would really really appreciate it. Thanks, Lucas McGill.
maybe someone here can help. I read threads here all the time, and
have gotten some help one or twice (who knows, maybe someday ill be
able to give advice).
Anyway, I'm trying to interface a simple circuit to my PC's
parallel port such that I can read 8-bits of data from an ADC. I have
several ADC0820's (http://cache.national.com/ds/DC/ADC0820.pdf) lying
around so I am going to try to use them. My current circuit is as
follows:
Pin 1: Vin
Pin 2: Pin 2 of Parallel Port
Pin 3: Pin 3 of Parallel Port
Pin 4: Pin 4 of Parallel Port
Pin 5: Pin 5 of Parallel Port
Pin 6: Pin 1 of Parallel Port
Pin 7: +5 volts
Pin 8: Ground
Pin 9: Not Connected
Pin 10: Ground
Pin 11: Ground
Pin 12: +5 volts
Pin 13: Ground
Pin 14: Pin 6 of Parallel Port
Pin 15: Pin 7 of Parallel Port
Pin 16: Pin 8 of Parallel Port
Pin 17: Pin 9 of Parallel Port
Pin 18: Not Connected
Pin 19: Not Connected
Pin 20: +5 volts
Note that I am not using resistors neither between my ADC and parallel
port nor between Vin and my ADC. Also note, Vin does not exceed +5
volts.
I currently have a small program (Visual Studio .NET) to see if my
circuit is working. Note that I am using Inpout32.dll
(http://www.logix4u.net/inpout32.htm) to access the parallel port.
What I would is when I touch a wire lead from Vin to +5 volts to see
255 printed to my computer monitor, and when I touch the wire to ground
to see 0 on the screen. What I DO see is 189 or 188 printed to the
screen when I touch the wire to +5 volts and 3 or 4 when I touch the
lead to ground. I am very confused
My (pseudo) Code:
Out(890,32); //Turn on "Bi-Directional" mode and set pin 1 (pin 6
of ADC0820) high.
while(1)
{
Out(890,33); //Set pin 1 (pin 6 of ADC0820) low while
keeping bit 5 high.
Out(890, 32); // Set pin 1 (pin 6 of ADC0820) high again.
printf("%d\n", In(888) );
}
END OF CODE
Note pin 1 of parallel port is inverted so a 1 sets the pin to low.
Parallel Port Reference: http://www.logix4u.net/parallelport1.htm
What ISN'T wrong. My parallel port is ECP mode and DOES support
bi-directional functionality, the ACD0820 chip is in working condition,
and my parallel port is in working condition. Anyway, I hope someone
has some experience with these issues and could give me some advice. I
would really really appreciate it. Thanks, Lucas McGill.
