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 Post subject: RS-232 Handshaking Lines used by Univ. Interface
PostPosted: Fri Mar 09, 2012 10:06 am 

Joined: Wed Mar 07, 2012 7:58 pm
Posts: 6
What other RS-232 handshaking lines in addition to the Request To Send (RTS) are you using with the Universal Interface in SIO2PC mode and using your APE software?

Last night I connected one of these simple RS-232 signal analyzers that use LEDs to indicate the signal state to the PC I'm using to interface with my 800XL (but without any of the either two pieces of interface HW I own connected on the end) to see what the initial state of the serial port signals were after being set up by the APE or SIO2PC.com software.

From what I observed, the only other RS-232 handshaking signal I saw being used by either APE or SIO2PC.com was the Data Terminal Ready (DTR) line. This is being set by APE, but not by SIO2PC.com.

Since I don't have the circuit schematics for your Universal Interface hardware, I can only guess or manually trace the RS-232 lines in/out of the 14C89 line driver IC on your board. From what I understood regarding your reply to my previous post, the GAL is used to automagically switch the Universal Interface from SIO2PC to ProSystem mode.

I'll post the results of the trial using another PC when I get around to it, not sure if I'll have enough time today for that.


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 Post subject: Re: RS-232 Handshaking Lines used by Univ. Interface
PostPosted: Fri Mar 09, 2012 11:51 am 

Joined: Wed Mar 07, 2012 7:58 pm
Posts: 6
I have found what I believe is the problem, after testing the RS232 line status after program initialization using another PC with an Intel motherboard in it: somehow APE is not properly setting the DTR line high on my unit with the AOpen motherboard. SIO2PC.com is able to correctly set DTR high in both test cases. Steve, do you any ideas what could be causing this?

I also sanity checked using Procomm Plus on the AOpen unit, it sets DTR correctly high as well.


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 Post subject: Re: RS-232 Handshaking Lines used by Univ. Interface
PostPosted: Sat Mar 10, 2012 7:17 am 
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Joined: Tue Aug 05, 2003 9:55 am
Posts: 1039
Location: Cleveland, Ohio
APE for DOS will not set/change DTR because its not used. The ProSystem software uses the DTR line to set /COMMAND, but in SIO2PC mode it is not used.

RTS is used to set the mode of the SIO2PC interface. RI, CTS and DSR can be used as the /COMMAND input.

Start with tracing RTS through your cable and into the 1489 IC of the interface. If that is set correctly, you should see output on the APE RS232 connectors TX pin when the Atari is sending data.

Steve


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 Post subject: Re: RS-232 Handshaking Lines used by Univ. Interface
PostPosted: Tue Mar 13, 2012 4:31 pm 

Joined: Wed Mar 07, 2012 7:58 pm
Posts: 6
Steve, I am down in my basement workshop now checking out the wiring and voltage levels of my current setup with the Univ. Interface and the PC unit with the AOpen motherboard. The wiring traces out OK from the RTS pin #7 on the DB9/RS232 to pin #10 Input C on the 14C89. The voltage level after PC boot is about -9.5V; after I start APE it changes to about +8.75 volts. Comparing these results to the other PC I have, the results are inverted: I'm getting positive voltage on RTS after boot and negative voltage after I start APE, and everything works as expected. Is there a possible HW initialization issue with the UART on the AOpen motherboard unit? If you want I can crack that unit open and find out what kind of UART chip is mounted on that mobo. SIO2PC works because I can flip the voltage on RTS using the Lock Data Line option, but I can't use APE - I think what is happening is that you're setting RTS but the RS232 output voltage on this unit is the opposite of what should be coming out. Have you ever seen anything like this before?

I also checked this on the other serial port of this unit (COM2) and it's the same situation.

I'd really like to use this particular unit for this project instead of having to set up something else...


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