On Mon, 2012-06-25 at 16:16 +0430, Robot Abzar Team wrote:
> Hi ,
> 
> I could solve the problem , it was not about software or hardware , just I
> have to change something in BIOS .
> Now machine work nice and perfect .
> 
> Regards
> Parviz

Just to fill some details. Since a BIOS setting fixed the problem, the
motherboard parallel port must be the port used with the G540 in this
case. The BIOS has a setting to enable the port, a setting for the
address used, plus a mode setting. The G540's drive enable input (charge
pump)
http://wiki.linuxcnc.org/cgi-bin/wiki.pl?About_Charge_Pumps 

pin needs a fair amount of drive to get it to enable the drive, but with
the parallel port pin which is normally used, has an open collector
configuration which can be thought of as a simple switch. Switches can
open or close a connection, but can't drive a load, so the drive enable
doesn't work. One fix (workaround, or hack, depending on ones view) is
to put the parallel port into EPP mode, which for most common parallel
ports happens to change how the parallel port drives the enable pin and
can usually drive the G540 enable pin.

If an add on parallel port is used, the BIOS can't be used to change the
mode of the new port. The port needs to have a utility or software
driver to set the mode.

Another option is to leave the parallel port pin as an open collector
switch and add a buffer chip or pull-up resistor. The pull-up, being
tied to +5 Volts, supplies power to the enable signal and drives the
G540 pin, the parallel port pin shorts the signal to ground as needed.
Or, usually the open collector output has a tiny bit of drive and a
buffer chip can be used to boost it.

The G540 also has a an enable override switch that can force the drive
to be enabled.

Some of my files on my study of the G540:
http://wallacecompany.com/machine_shop/G540/ 

Tracing the enable signal:
http://wallacecompany.com/machine_shop/G540/G540_upper_bottom_z-1b.png 

Motherboard signal with SPP mode:
http://wallacecompany.com/machine_shop/G540/g540_mb_spp.jpg 

note that the signal only goes to two Volts.

Motherboard signal with EPP mode:
http://wallacecompany.com/machine_shop/G540/g540_mb_epp.jpg 

note that the signal is boosted to about 3.2 Volts which is enough to
get the enable to work.

Here is a buffered signal:
http://wallacecompany.com/machine_shop/G540/g540_siig_buf.jpg 

which gives a full 5 Volt swing.


-- 
Kirk Wallace
http://www.wallacecompany.com/machine_shop/
http://www.wallacecompany.com/E45/index.html
California, USA


------------------------------------------------------------------------------
Live Security Virtual Conference
Exclusive live event will cover all the ways today's security and 
threat landscape has changed and how IT managers can respond. Discussions 
will include endpoint security, mobile security and the latest in malware 
threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
_______________________________________________
Emc-users mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/emc-users

Reply via email to