Dynomotion

Group: DynoMotion Message: 6875 From: funncarsmi Date: 3/4/2013
Subject: Digital Out
1) JP4 and JP6 diagrams show 8 digital I/O that are limited to 3.3VDC, but it isn't clear if ports 5-7 and 10-16 provide the +3v power when active or if they connect to ground when active. I connected a 3v diode ...from the +3vDC (port 3) and port 4. The led is dim when off and bright when on. What is causing the led to light dim when off? Connecting it to port 4 and ground (port 8) it appears to work correctly. I guess this means each port has a 3vdc output when active (which is opposite of what I need. I need to bring the channel to ground when active).

I have an external Opto board with 16 inputs. The inputs have a common +5VDC and bringing any of the other input wires to ground will activate the 24VDC circuit. I believe I can activate this external opto board with 3VDC, but this won't be confirmed until later this week. Assuming this board will run off of 3VDC, How can I bring 16 channels to ground using the digital I/O? If I need to run it off of 5VDC, Bringing each line to ground to activate it... do you have any suggestions?

-Gregg
Group: DynoMotion Message: 6877 From: Tom Kerekes Date: 3/5/2013
Subject: Re: Digital Out
Hi Gregg,

Normally we refer to the numbers on a connector as "Pins" rather than "Ports".

There are actually 10 digital I/O on each connector and all 10 are 3.3V Signals.  The first 8 of 10 have 150ohm pull down resistors.

In general the KFLOP IO have 3 states (tri-state).  They can either drive high to 3.3V (source current) or drive low to ground (sink current) or float open (as an input).

The 8 I/O with pull downs will not really float as inputs because they have a pull down resistor hard wired to them.

When selected as an Output and Set the IO will drive to 3.3V.  When selected as output and Clear the IO will drive to 0V.

All the IO have ESD protection diodes connected to GND and the 3.3V Supply.  For this reason KFLOP will be damaged if any of the 3.3V IO are forced above 3.8V or below -0.5V.

Usually 5V LEDs (with common anodes) can be controlled by driving the IO to GND (Output and Clear) and float (Input).  In this mode the LED will see either about 5V - 0.4V = 4.6V or 5V - 3.8V = 1.2V.  Because most LEDs require more than 1.2V to turn on this usually works.   But this won't work with the 16 IO with hard wired pull down resistors.

In most cases you will be in control of the IO and are free to set or clear it as required so actual polarity usually doesn't matter.

HTH
Regards
TK


Group: DynoMotion Message: 6886 From: funncarsmi Date: 3/6/2013
Subject: Re: Digital Out
Tom, Thanks. I confirmed my opto board only needs 1.7V to activate it, so the 3V is working perfectly. Using the clearbit16 command instead of the Setbit16=0 solved my other problem.

-Gregg

--- In DynoMotion@yahoogroups.com, Tom Kerekes <tk@...> wrote:
>
> Hi Gregg,
>
> Normally we refer to the numbers on a connector as "Pins" rather than "Ports".
>
> There are actually 10 digital I/O on each connector and all 10 are 3.3V Signals.  The first 8 of 10 have 150ohm pull down resistors.
>
> In general the KFLOP IO have 3 states (tri-state).  They can either drive high to 3.3V (source current) or drive low to ground (sink current) or float open (as an input).
>
> The 8 I/O with pull downs will not really float as inputs because they have a pull down resistor hard wired to them.
>
> When selected as an Output and Set the IO will drive to 3.3V.  When selected as output and Clear the IO will drive to 0V.
>
> All the IO have ESD protection diodes connected to GND and the 3.3V Supply.  For this reason KFLOP will be damaged if any of the 3.3V IO are forced above 3.8V or below -0.5V.
>
> Usually 5V LEDs (with common anodes) can be controlled by driving the IO to GND (Output and Clear) and float (Input).  In this mode the LED will see either about 5V - 0.4V = 4.6V or 5V - 3.8V = 1.2V.  Because most LEDs require more than 1.2V to turn on this usually works.   But this won't work with the 16 IO with hard wired pull down resistors.
>
>
> In most cases you will be in control of the IO and are free to set or clear it as required so actual polarity usually doesn't matter.
>
>
> HTH
> Regards
> TK
>
>
>
>
> ________________________________
> From: funncarsmi <funncars@...>
> To: DynoMotion@yahoogroups.com
> Sent: Monday, March 4, 2013 8:34 PM
> Subject: [DynoMotion] Digital Out
>
>
>  
> 1) JP4 and JP6 diagrams show 8 digital I/O that are limited to 3.3VDC, but it isn't clear if ports 5-7 and 10-16 provide the +3v power when active or if they connect to ground when active. I connected a 3v diode ...from the +3vDC (port 3) and port 4. The led is dim when off and bright when on. What is causing the led to light dim when off? Connecting it to port 4 and ground (port 8) it appears to work correctly. I guess this means each port has a 3vdc output when active (which is opposite of what I need. I need to bring the channel to ground when active).
>
> I have an external Opto board with 16 inputs. The inputs have a common +5VDC and bringing any of the other input wires to ground will activate the 24VDC circuit. I believe I can activate this external opto board with 3VDC, but this won't be confirmed until later this week. Assuming this board will run off of 3VDC, How can I bring 16 channels to ground using the digital I/O? If I need to run it off of 5VDC, Bringing each line to ground to activate it... do you have any suggestions?
>
> -Gregg
>