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DTR and RTS


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#1 TheMontezuma OFFLINE  

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Posted Tue Mar 14, 2017 12:25 PM

Does anybody have an idea why Fatih Aygun wanted to clear DTR and RTS lines in AspeQt?



#2 TheMontezuma OFFLINE  

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Posted Wed Mar 22, 2017 11:01 AM

No answers here, so I will give some feedback on my research.

It seems there is no real reason to clear these signals.

Generally a DCE device may even require DTR (Data Terminal Ready) in order to talk to the DTE.

RespeQt is not using the RS232 hardware handshake, instead it is monitoring the state of the Atari command line connected to CTS, DSR or RI, so nobody takes care about DTR or RTS.

Almost nobody...

I was asked for help by somebody playing with one of the Arduino board, which was simply passing data between the real serial port connected to ATARI and the software serial port (USB).

Unfortunately RespeQt could not see any data coming (I/O calls were blocking), however PUTTY worked as expected showing bytes coming from ATARI.

I compared the sequence of serial port initialization between Putty and RespeQt (using PortMon) and realized that Putty is setting the DTR and RTS lines regardless of the handshake settings. For me it looks that the virtual serial port driver does not pass incoming data as long as we do not set DTR...

A small change in RespeQt helped :)



#3 _The Doctor__ OFFLINE  

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Posted Wed Mar 22, 2017 9:52 PM

Not understanding what your getting at....

It's not a full blown rs232 emulator... It's a SIO emulator and only the common drives etc....

I would love a full blown all device emulator on a pc.. as some of the earlier 3rd party devices on the 800 had full flow control or some times completely their own standards of communication many used ports 3 and 4 on the front of the 800 also... over time some of those pads, paper tape readers, and control systems have been purchased by users here on Atari Age... often a mention but nothing else other than they have it.... I wish the software would be archived.. picture taken.. maybe a youtube video and some sort of write up would be done.... many time they just put it away and forget about it... in the dark dank collection pen until they pass on, cash out, or push up daisies.... then the family tosses it out in the bin... lost forever... sigh


Edited by _The Doctor__, Wed Mar 22, 2017 9:53 PM.


#4 TheMontezuma OFFLINE  

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Posted Thu Mar 23, 2017 2:25 AM

I mean, we use RS232 port on a PC to connect to the Atari SIO port (this is what SIO2PC is all about):

Connecting RxD, TxD lines to Data Out, Data In lines is obvious. We also connect SIO's Command Line to one of the RS232 lines (CTS, DSR or RI).

Now, in order to emulate a SIO device, the PC emulation software uses the RS232 port.

In particular the RS232 "hardware handshake" is not used, instead one of the control lines (CTS, DSR or RI) is monitored to detect the high state of the SIO command line.

Now depending on the serial port driver implementation (on a PC) everything can go fine or not...

This is what I described above about Arduino.

 

I guess you meant devices similar to ATARI 850 (providing ATARI with RS232 capabilities)?



#5 Joey Z OFFLINE  

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Posted Tue Apr 11, 2017 2:20 PM

There are SIO2PC devices which may use the DTR or the RTS signals to select the mode, either to enable them or to set them to SIO2PC mode (vs, for example, 10502PC mode). I seem to remember the Atarimax RS232 SIO2PC needs one of these lines set properly, though I could be mistaken.



#6 DrVenkman OFFLINE  

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Posted Tue Apr 11, 2017 3:35 PM

There are SIO2PC devices which may use the DTR or the RTS signals to select the mode, either to enable them or to set them to SIO2PC mode (vs, for example, 10502PC mode). I seem to remember the Atarimax RS232 SIO2PC needs one of these lines set properly, though I could be mistaken.

 

Yeah, I think Joey is onto something here. I have one of Ray's previous-generation dual-mode SIO2PC/10502PC dual-mode devices - I used it in the past to image my old floppies to .atr files. I don't recall what specifically about it switches modes, but the way it's designed, it cannot work with real Atari disk drives on the SIO chain as the Atari computer. However, it can be used to connect a drive directly to a modern device to make disk copies. At the time I bought it, Ray's advice to users was to use APE/ProSystem to do the disk imaging, and to use AspeQt to do other, general peripheral emulation with the resulting .atr files, which is what I did. 

 

But that brings up another question: can RespeQt do this? That is, act as the "host device" on the SIO chain and make copies of existing disks? I don't think it can, can it? If not, is it something that might be added at some point further down the roadmap? 


Edited by DrVenkman, Tue Apr 11, 2017 3:36 PM.


#7 Joey Z OFFLINE  

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Posted Tue Apr 11, 2017 4:19 PM

 

Yeah, I think Joey is onto something here. I have one of Ray's previous-generation dual-mode SIO2PC/10502PC dual-mode devices - I used it in the past to image my old floppies to .atr files. I don't recall what specifically about it switches modes, but the way it's designed, it cannot work with real Atari disk drives on the SIO chain as the Atari computer. However, it can be used to connect a drive directly to a modern device to make disk copies. At the time I bought it, Ray's advice to users was to use APE/ProSystem to do the disk imaging, and to use AspeQt to do other, general peripheral emulation with the resulting .atr files, which is what I did. 

 

But that brings up another question: can RespeQt do this? That is, act as the "host device" on the SIO chain and make copies of existing disks? I don't think it can, can it? If not, is it something that might be added at some point further down the roadmap? 

This functionality belongs in a separate software package IMHO



#8 _The Doctor__ OFFLINE  

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Posted Fri Nov 3, 2017 7:21 PM

you know the more I think about this... would it be cool to load up 4,8, or 16 drives with images and then be able to select write to real disk, have respeqt flip to host mode and write out those images to one selected drive or 4,8, 16 real drives?  Yes fully aware of the need to use a soldering iron etc. for the higher disk numbers...but still a cool as heck disk reconstitution system... a step further to include bit writer or other protocols down the road?

 

Par teh Par teh Ja!


Edited by _The Doctor__, Fri Nov 3, 2017 7:24 PM.




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