Is the RS485 connected with one pair + ground (half duplex) or with two pai=
rs + =

ground (full duplex RS422 mode)?

If it is in half duplex mode you have to make sure that the DE (driver enab=
le) =

pin on the MAX3080E is activated (set high) from the software. If it is in =
full =

duplex mode it may still need to be activated by software but then it can a=
lso =

be clamped high directly on the PCB.

/Ruben


> =

> Hi
> =

> I'm picking up some legacy code for a PCB controlled by an '18F4550 and h=
ave got
> a problem that is confusing me. I'm not v experienced with 18F devices or=
 C-18,
> so it may be a silly mistake.
> =

> The EUSART transmits via a MAX3080E chip (RS485 transceiver), then down a
> short length of cable to an RS485 to USB converter (a USB-COMi-M) and int=
o a mac
> running ZTerm. The below code snippet functions fine: [code] while(1) {
>      putch('x');
> }
> [/code]
> in that it writes a continuous stream of 'x's to ZTerm. If I try to send
> individuals bytes, or a short stream, like this:
> [code]
>      putch('x');
>      putch('x');
>      putch('x');
> [/code]
> then I don't get any output on ZTerm. No other settings are changed betwe=
en the
> two experiments. Any ideas why this might be?
> =

> RCSTA is set to: b'10010100'
> TXSTA is set to: b'10100110'
> BAUDCON is: b'01000000'
> Baud rate is 19.2k.
> =

> The EUSART is running from the internal oscillator, which I know isn't
> perfect, but it's an inherited PCB and I can't do much about it.
> =

> Many thanks for any pointers.
> =

> Btw. I also tried to post this message on the Microchip forums, but it
> looked like it got bounced back repeatedly - but in case it later pops up
> there, apologies for any double posting.
> =

> Jamie
> =

> =

> -- =

> View this message in context:
> http://www.nabble.com/EUSART%2C-%2718F4550%2C-Continuous-stream-of-bytes-=
transmi
> ts%2C-but-single-bytes-don%27t...-tp20326923p20326923.html Sent from the =
PIC -
> [PIC] mailing list archive at Nabble.com.
> =

> -- =

> http://www.piclist.com PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
> =


=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D
Ruben J=F6nsson
AB Liros Electronic
Box 9124, 200 39 Malm=F6, Sweden
TEL INT +46 40142078
FAX INT +46 40947388
ruben@pp.sbbs.se
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D

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