|Trouble with RS-232/HP-IL Interface (HP 82164A)|
Message #1 Posted by Hans Holzach on 6 Jan 2013, 1:02 p.m.
thanks to the help of forum members i was able to solve a problem with my HP clock/HP-IL/HPIB setup. i could need some advice again. this time it's about the infamous RS-232/HP-IL interface (HP 82164A).
i'd like to connect my garmin gps (gpsmap 60cs) to the interface and read NMEA data into my HP 71B, following the setup egan ford suggests (link). the gps sources the data correctly. i can connect the gps to my mac via a serial/usb adapter and monitor the NMEA data at 4800 baud, 8/1 bit, XON/XOFF, no parity. that part seems to work properly.
i am also able to set the control and character registers of the interface, either by DDL or REMOTE, and read them. the status bytes are a bit strange, because byte 4 is 11110000 or 01110000, although it should be 00000000 according to the manual, as this byte is "reserved for future use". bytes 1 to 3 seem to be fine.
the internal jumper is set to DTE.
but when i try to read the NMEA data from the gps, i don't get a byte of data into the register (ENTER USING "#,nA";G$ with FLAG -23 clear or just ENTER;G$ with FLAG -23 set). with flag -23 clear the T/R light is permanently on, with the controller sending one SDA after the other, or flashes up once with FLAG -23 set.
when i disconnect the gps from the interface the result is the very same. it seems as if no data is sent from the RS-232 side to the HP-IL side and vice versa.
am i facing a hardware problem here, or did i just miss something?
thank you very much for your help!
edited to add info about internal jumper
Edited: 6 Jan 2013, 1:10 p.m.