Millisecond Forums

Sending sub-millisecond TTL pulses through parallel port

https://forums.millisecond.com/Topic20464.aspx

By aMargolis - 1/11/2017

Hi guys,

This is just a quick one.

I am using a stimulation device which is operated through the parallel port. In order to program the intensity of the stimulation, I need to set the control pin to "high" for 0.5ms or less, and then set it back to "low". This tells the device that I'm about to send it intensity data.

However it doesn't seem possible to send sub-millisecond pulses through the parallel port using Inquisit 4. Can anybody confirm this?

Many thanks,
By Dave - 1/11/2017

aMargolis - Wednesday, January 11, 2017
Hi guys,

This is just a quick one.

I am using a stimulation device which is operated through the parallel port. In order to program the intensity of the stimulation, I need to set the control pin to "high" for 0.5ms or less, and then set it back to "low". This tells the device that I'm about to send it intensity data.

However it doesn't seem possible to send sub-millisecond pulses through the parallel port using Inquisit 4. Can anybody confirm this?

Many thanks,

> However it doesn't seem possible to send sub-millisecond pulses through the parallel port using Inquisit 4. Can anybody confirm this?

Yes, that is correct / I can confirm. I'm surprised by the 0.5 millisecond requirement of your device, though, because timing error for parallel ports are generally on the order of ~1ms, i.e. 0.5 ms would fall well below a typical parallel port's timing accuracy.

Have you tried if the device accepts the intensity data even if you raise the control pin for longer than 0.5 ms?
By aMargolis - 1/11/2017

Dave - Wednesday, January 11, 2017
aMargolis - Wednesday, January 11, 2017
Hi guys,

This is just a quick one.

I am using a stimulation device which is operated through the parallel port. In order to program the intensity of the stimulation, I need to set the control pin to "high" for 0.5ms or less, and then set it back to "low". This tells the device that I'm about to send it intensity data.

However it doesn't seem possible to send sub-millisecond pulses through the parallel port using Inquisit 4. Can anybody confirm this?

Many thanks,

> However it doesn't seem possible to send sub-millisecond pulses through the parallel port using Inquisit 4. Can anybody confirm this?

Yes, that is correct / I can confirm. I'm surprised by the 0.5 millisecond requirement of your device, though, because timing error for parallel ports are generally on the order of ~1ms, i.e. 0.5 ms would fall well below a typical parallel port's timing accuracy.

Have you tried if the device accepts the intensity data even if you raise the control pin for longer than 0.5 ms?
Thanks for the reply. It is strange that it requires a 0.5ms pulse, I agree, but I have an email from the manufacturer confirming that this is the case. 

I have tried longer pulses but unfortunately they don't work... Thanks for your help anyway, I guess I'll have to look for a different approach.