looking for a middle man - Electronic Circuits Projects Diagrams Free

dreamproject · 9th December 2004, 02:05 AM

Hi all,

Just came up with a devastating realization . My all-too-expensive LM629's , encoders steering setup will not work through the parallel port. The number or i/o lines to "talk" to the 629's aren't enough . I am just thinking aloud . Could I use an intermediate micro-controller to recieve commands from the PC ( 4 bits ), 16 commands are enough and then the micro-controller to output hex instructions for the 629 to understand . Since my position , vel,accn co-efficients are going to be constant ( the motor shaft moves through a fixed pos,at const vel,accn
[10 degrees , 500 rev/s and 0.1 rad/ s/s]
for every 1v change in the joystick pot) . Why then a PC ? for one - I can display a virtual steering and other input data such a joystick pos . But the important reason is that joystick inputs are read by the computer.

Any other suggestions on how this could be implemented

Thanks

bmcculla · 9th December 2004, 06:45 AM

A micro should work for this app. The serial port is usualy used for PC to micro communication rather than the Parallel port.

If you want a simple solution J.R. Kerr sells a PIC with a PID controller pre-programed in. You just send it commands. Its designed to talk to the serial port.

checkmate · 9th December 2004, 07:15 AM

One common trick to increase the number of I/O lines is to use data latches.
1 octal latch : 8 outputs from 9 inputs
2 octal latches : 16 outputs from 10 inputs
3 octal latches : 24 outputs from 11 inputs
4 octal latches : 32 outputs from 11 inputs
and so on.

How many do you need?

williB · 9th December 2004, 02:56 PM

if you want to use an ISA bus PC, my circuit can/will give you 8 input bits and as it currently configured 4 ,individually controlled outputs..
http://www.electro-tech-online.com/v...r=asc&start=90
oh the last page has the circuit drawn with eagle..

nbucska · 9th December 2004, 07:06 PM

The PC-s parallel port [PP] has three busses:

Data bus output 8bits (D0-D7) Adr= BASE
Sense bus input 5 bits (S3-S7) Adr=BASE+1
control bus output 4 bits (C0-C3) adr=BASE+2

S7,C0,C1 and C3 are inverted.
Under DOS the BASE can be found at 0x0000:0x0408 and ....409
(Lsb-Msb)

I would use C for address and D for data out, S for data in.

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9th December 2004, 02:05 AM	(permalink)
dreamproject	looking for a middle man Hi all, Just came up with a devastating realization . My all-too-expensive LM629's , encoders steering setup will not work through the parallel port. The number or i/o lines to "talk" to the 629's aren't enough . I am just thinking aloud . Could I use an intermediate micro-controller to recieve commands from the PC ( 4 bits ), 16 commands are enough and then the micro-controller to output hex instructions for the 629 to understand . Since my position , vel,accn co-efficients are going to be constant ( the motor shaft moves through a fixed pos,at const vel,accn [10 degrees , 500 rev/s and 0.1 rad/ s/s] for every 1v change in the joystick pot) . Why then a PC ? for one - I can display a virtual steering and other input data such a joystick pos . But the important reason is that joystick inputs are read by the computer. Any other suggestions on how this could be implemented Thanks __________________ the best bet yet...

9th December 2004, 06:45 AM	(permalink)
bmcculla	A micro should work for this app. The serial port is usualy used for PC to micro communication rather than the Parallel port. If you want a simple solution J.R. Kerr sells a PIC with a PID controller pre-programed in. You just send it commands. Its designed to talk to the serial port.

9th December 2004, 07:15 AM	(permalink)
checkmate	One common trick to increase the number of I/O lines is to use data latches. 1 octal latch : 8 outputs from 9 inputs 2 octal latches : 16 outputs from 10 inputs 3 octal latches : 24 outputs from 11 inputs 4 octal latches : 32 outputs from 11 inputs and so on. How many do you need?

9th December 2004, 02:56 PM	(permalink)
williB	if you want to use an ISA bus PC, my circuit can/will give you 8 input bits and as it currently configured 4 ,individually controlled outputs.. http://www.electro-tech-online.com/v...r=asc&start=90 oh the last page has the circuit drawn with eagle..

9th December 2004, 07:06 PM	(permalink)
nbucska	The PC-s parallel port [PP] has three busses: Data bus output 8bits (D0-D7) Adr= BASE Sense bus input 5 bits (S3-S7) Adr=BASE+1 control bus output 4 bits (C0-C3) adr=BASE+2 S7,C0,C1 and C3 are inverted. Under DOS the BASE can be found at 0x0000:0x0408 and ....409 (Lsb-Msb) I would use C for address and D for data out, S for data in.