[WinXP/LabView7.0]Reading parallel port is too slow...

[LabViewFreak]

Hi,
First I would like to apologize for my English. I'm from Switzerland....
I'm trying to read out a 16Bit A/D in 1us steps. Serial Communication over a PIC is too slow, so I was looking for a faster option. I found out there is possibility to read from the parallel port:
I downloaded and installed the AccessHW drivers. I found 2 Vi's (see attached files) to read and write to the port. But this works only very slow. (100Hz read frequency).
By the way I need some advice how to use 16 bits in minimum as inputs. When I set the bit 5 in Baseregister+2 I can read the Baseregister. I can read the whole byte except bit 3. This bit stays always high (3.4 VDC).
The 5 status bits from Baseregister+1 I can
read with no problems but the read frequency is around 100Hz too...
The 4 control bits from Baseregister+2 I can't access. I followed the instructions in this link: http://zone.ni.com/devzone/conceptd.nsf/webmain/72C6FC6CE4AD4D1386256B1800794596?opendocument#4 to make this 4 bits inputs, but it doesn't work. I set the Baseregister+2 00100100 (all of the 4 bits are high) and then I start to read out the Baseregister+2, but there are no changes, when I connect one of the 4 pins to ground.

Hope there is anyone who can help me..!

Greets

[m3nth]

If you're trying to acquire a 16-bit sample at 1MS/s, using the parallel port, it will not work. In fact, many full-fledged DAQ cards do not support this high sampling-rate/resolution combination. Look at what NI has available here, in the S and E series DAQ boards--this should give you a feel for what's out there and what a professionally manufactured piece of equipment is capable of:

http://sine.ni.com/apps/we/nioc.vp?cid=10955〈=US
http://sine.ni.com/apps/we/nioc.vp?cid=1038〈=US

As you noted already, a parellel port is going to be extremely slow for your needs, and likely not only be slow, but also have a pretty fair amount of timing jitter, since the timing of your read calls will be indeterminate. I would definitely recommend you look into som
e other hardware acquisition option besides your parallel port... it won't get you very far unfortunately, because that isn't what it's really designed for.