02-20-2018, 08:20 AM
I've been trying to understand what I may be able to do with the *BL command with a Geneve 9640 computer.
Tim Tesch has a program called PORT that works well all the way up to 38400 on file transfers so I know it can be done. Myself, i am working on a different terminal emulator and I am getting a strange and reproducible response when doing Xmodem (128 byte) downloads.
I have not figured out what, but I can start a download at 38400 baud and the moment the 128 block reaches a transfer of 10,112 bytes, I error out.
I have experimented with the video display as it updates the bytes transferred, so I know the routine when it goes from a 4 character display to a 5 character display of bytes transferred, is one issue. I am right on the cusp of the CPU speed with too many cpu cycles away from capturing RS232 data. When I comment out the display of bytes transferred, it continues on past 10,112 until some other point when it then errors out.
At first, I thought it may have been tied to interrupts or the handshaking, but there may be something happening I am not fully comprehending. When I change the buffer limit with a AT*BL64, I do not even get the first block. If I go to the higher end of the limit, I get some other responses.
So, what I am wondering is what is the WiModem232 doing with a smaller buffer versus a larger buffer between a BBS (Mystic BBS software) back to the modem from where it then connects to my software and computer. I hope that is explained well enough.
Could there be a preferred or optimum BL setting for packet size with the file transfers.
Please note, it has been years since I have done any significant programming, and I am still pretty green at coding for an RS232 interface. However I saw some subtle differences if I varied the BL setting when I thought any changes to that setting should have had no impact on the file transfer.
Any insight would be appreciated.
Beery
Tim Tesch has a program called PORT that works well all the way up to 38400 on file transfers so I know it can be done. Myself, i am working on a different terminal emulator and I am getting a strange and reproducible response when doing Xmodem (128 byte) downloads.
I have not figured out what, but I can start a download at 38400 baud and the moment the 128 block reaches a transfer of 10,112 bytes, I error out.
I have experimented with the video display as it updates the bytes transferred, so I know the routine when it goes from a 4 character display to a 5 character display of bytes transferred, is one issue. I am right on the cusp of the CPU speed with too many cpu cycles away from capturing RS232 data. When I comment out the display of bytes transferred, it continues on past 10,112 until some other point when it then errors out.
At first, I thought it may have been tied to interrupts or the handshaking, but there may be something happening I am not fully comprehending. When I change the buffer limit with a AT*BL64, I do not even get the first block. If I go to the higher end of the limit, I get some other responses.
So, what I am wondering is what is the WiModem232 doing with a smaller buffer versus a larger buffer between a BBS (Mystic BBS software) back to the modem from where it then connects to my software and computer. I hope that is explained well enough.
Could there be a preferred or optimum BL setting for packet size with the file transfers.
Please note, it has been years since I have done any significant programming, and I am still pretty green at coding for an RS232 interface. However I saw some subtle differences if I varied the BL setting when I thought any changes to that setting should have had no impact on the file transfer.
Any insight would be appreciated.
Beery