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Operating the RS-232 serial ports

1) Why dealing with serial ports?

Reasoning and procedureS Inc. has a long tradition in designing embedded applications, where the use of serial ports is a tradition.  Since ZTree is also used by a great number of designers in this area we decided to keep this original feature.  The serial ports can be used also for transferring files from Windows based computers to DOS based prototypes or even old DOS computers used in large Embedded Systems. As a tool for Embedded Systems applications, it makes an easy way to simulate the behavior of a peripheral.  A typical application of this feature is the use of your work station to produce a series of small files containing strings that represent commands and other data to be sent to an embedded application prototype.  You can use either a regular editor or the binary options of ZTree View command to produce those files. They can be then highlighted and sent through the Comm port with the 'O' command.  Output from the interfaced computer can be captured and recorded in files also, for posterior analysis.

2) What are the baud rates supported by rpVT?

110 to 115200 baud.

3) How do I transfer files between 2 Windows computers or between a Windows and a DOS computer?

If you connect the serial ports of both computers with a null-modem type cable, you can send and receive full files in baud rates from 1200 to 115200.  The computers that will be using Windows will run ZTree/rpVT and the computers running DOS will use two small executables, written by Genese Inc., called “fl2rs.exe and rs2fl.exe”, both them capable of operating with several different baud rates for sending or receiving the files. They use Comm ports 1 & 2, only.

4) What is the syntax of the 2 DOS executables?

rs2fl port/baud filename.ext
fl2rs port/baud filename.ext
(All parameters are mandatory)
  1 or 2
Baud: Note that rs2fl & fl2rs suport 1200-115200 (not 110,150,300 etc.)
         1 - 115200
         2 - 57600
         3 - 38400
         4 - 28800
         5 - 23040
         6 - 19200
         7 - 9600
         8 - 4800
         9 - 2400
         0 - 1200
         (file should be present at the directory where the program is executed)
Example: rs2fl 27 book1.dat

5) Can I use any combination of computers like W/W, W/D & D/D?

Yes. It serves also as a simple way to exchange data between primitive architecture computers that have no other ways to communicate except via serial ports.  This means, for example, old DOS machines that have no way to go in LANs or other ways of exchange data with the new Win32 ones.

6) Is there any speed limitation specially on the old DOS machines?

Yes, the operating system on some very old DOS machines sometimes takes too long in the interrupt disable state while reading or writing files and an overrun on very high baud rates 'eats' one or two bytes.  Try sending the files in 57600 (or even 38400) instead of 115200 to see if it passes without errors. Remember to change the Baud rate to the same value in both computers.  

7) How can I check if the file was transmitted without errors?

If you do not transmit 'hundreds' of files, a simple way to check integrity is to copy the file back to the transmitting computer with a different name and test for equality. In DOS you can use the command 'fc' and in the rpVT side you can just compare the CRCs.

8) What are the transmit/receive commands in the rpVT side?

When you highlight a file in ZTree and use the command 'O' in rpVT, the selected file is transmitted via the serial port and you can follow the progress of the transmission by checking the numbers in rpVT top bar. Similarly, when you need to receive a file, you use the command 'I' in rpVT and the received data is loaded into a file called 'dump.dat' in the current ZTree directory or to the 'Output file' if active. Read about Output File in the 'Y' commands. The sequence is always: Start the receiving process first and then trigger the transmitting process in the other computer.

rpvt/rpvt_viewer_treater.txt · Last modified: 2018/12/10 20:53 by admin