- From: Franco Minutiello <franco.minutiello_at_darts.it>
- Date: Fri, 15 Jul 2005 13:15:03 +0200
Hello,
I'm a comedi newbye. I'm trying to use a parallel port to manage digital
I/O.
The system is a debian sarge (kernel 2.4.27) with library downloaded as
debian package and modules compiled from sources.
The modules are installed. successfully.
The output of cat /proc/comedi is:
comedi version 0.7.70
format string: "%2d: %-20s %-20s %4d",i,driver_name,board_name,n_subdevices
0: comedi_parport parport 4
comedi_parport:
comedi_parport
The modules are autoloaded from modules.conf by the following lines
alias char-major-98 comedi
alias char-major-98-0 comedi_parport
post-install comedi_parport /usr/sbin/comedi_config /dev/comedi0
comedi_parport 0x378,7
I wrote a simple class to manage I/O using subdevice 0
It seems ok but the value read after setting a bit are different from I
expect.
Nothing is connected to parallel port.
Setting a single bit seems to modify a bunch of bits.
Here is the output sequence
setting bit 7 to 0
11111111
setting bit 6 to 0
11111111
setting bit 5 to 0
00001111
setting bit 4 to 0
00001111
setting bit 3 to 0
01100011
setting bit 2 to 0
11000110
setting bit 1 to 0
01011000
setting bit 0 to 0
01100100
Overall info
Version Code : 1862
Driver name : comedi_parport
Board name : parport
Subdevices : 4
Subdevice 0
channels : 8
flags : 30000
type : Digital input/output
The same program using subdevice 2 the output setting seems ok.
Is there something wrong in reading the bit values from a I/O subdevice
set as output channel?
Which is the right right parallel port configuration from BIOS (EPP,
SPP, ...)?
Any help will be appreciated.
Franco
--
------------------------------------------------------------------------
Franco Minutiello - DARTS Engineering srl
Tel: +39-010-5761240 Fax: +39-010-5760224
s-mail: Via T. Invrea 14 /2 16129 GENOA (ITALY)
e-mail: franco.minutiello_at_darts.it <mailto:franco.minutiello_at_darts.it>
Received on 2005-07-15Z10:15:03