bjh@linus.UUCP (Brian Holland) (05/18/89)
I am having trouble communicating over the communications port of the VAXstation 2000. The port is allocated from a window on the vaxstation and set with the correct parameters for XON/XOFF I think. I open the port as a file from a C program with fopen(f2, "tta2:") where f2 is a file pointer and tta2: is the name of the port. I talk to a 68020 board by sending messages out the port and reading from the port for its response. I have no problem sending large messages (>512 bytes) out the port, but if the 68020 board tries to send something larger than 512 bytes the port seems to eat everything that came before the 512th byte. I read the port with fgetc(f2, c) and find only the trailing part of the message. I hooked a serial line analyzer to the port and the message is coming across. At the 511th byte the port generates an XOFF followed by an XON. Does anyone have an idea what is going on or why the port would eat the beginning of the message ? I am considering limiting message sizes to less than 512 but would rather not have to change the code I have written so far. Thanks in advance, Brian Holland Mitre Corporation bjh@mitre-bedford.arpa bjh@linus.mitre.org -- () Brian Holland bjh@mitre-bedford.arpa (alt: bjh@linus) VHSIC Technical Center-CAD Section The MITRE Corporation; MS E095; Bedford, Ma. 01730; tel: 617-271-3789