50G Serial port - 1200 bauds possible
Claudio Lapilli
After building my own serial interface, I started a series of tests.
It turns out that as I guessed in a previous thread, there is no
reason why the calculator cannot communicate at 1200 bauds.
I still cannot understand the absurd and arbitrary decision of
dropping compatibility with those lower speeds. In any case, I'm not
writing this post to complain, but to bring a simple solution:
Write the following program, it requires library 256 to be attached:
<< 16. * 48000000. / INV 0. RND 1. - R->B ->H 11. 18. SUB #07500028h
SWAP POKEARM >>
[replace the <<, >>, -> symbols with the proper ones]
I'll assume it was stored with the name 'SETSPEED'.
To use it, simply set all parameters to establish a serial
communication at any speed, then go back to the calculator stack and
execute:
OPENIO
1200 SETSPEED
(where SETSPEED obviously calls the program given above)
>From now on, all communications will happen at 1200 bauds (or any
other arbitrary speed). It will work at your selected speed until the
port is closed with CLOSEIO.
Luckily, the Transfer application doesn't touch the port if it's
already open, so it will work even when using the nice UI to transfer
files (the screen will show the speed you had selected before, simply
disregard since SETSPEED overrides the speed at a much lower level and
the UI is not aware of that).
I tested it transferring a directory at 110 bauds, 300 bauds, 1200
bauds and it worked fine. I didn't wait for the transfer to finish at
110 bauds because in Kermit mode it was transferring 4 bytes per
second (my dir was 8kbytes), that's more than what my patience can
take for now.
Regards,
Claudio
John H Meyers
> OPENIO
> 1200 SETSPEED [using simple provided program]
Wow! I hope HP gives you a commission on all the extra HP50G sales
which you just made possible!
[r->] [OFF]
dot
Great work, Claudio! Bravo! You've just significantly enhanced the
hp50 for me. Thank you v-e-r-y much!
-Dot-
Claudio Lapilli
<...>
> It turns out that as I guessed in a previous thread, there is no
> reason...
In the rush, I forgot the link. For completeness, here's the original
thread:
http://groups.google.com/group/comp.sys.hp48/browse_frm/thread/2011bdbca2233763
Claudio
James M. Prange
> Hello,
> After building my own serial interface, I started a series of tests.
> It turns out that as I guessed in a previous thread, there is no
> reason why the calculator cannot communicate at 1200 bauds.
> I still cannot understand the absurd and arbitrary decision of
> dropping compatibility with those lower speeds.
Indeed, most often, we'd like higher speeds, but for external I/O,
we have to settle for a bit rate that both devices can use.
> In any case, I'm not
> writing this post to complain, but to bring a simple solution:
>
> Write the following program, it requires library 256 to be attached:
Actually, although it does require that the development library be
attached for compiling (when the ENTER key is pressed, or an ASCII
file is downloaded), once compiled, it will work the same even
without the development library attached.
Other than that, without the development library attached, the
menu 256 keys can be used for non-programmable operations,
although not for programmable commands.
> << 16. * 48000000. / INV 0. RND 1. - R->B ->H 11. 18. SUB #07500028h
> SWAP POKEARM >>
>
> [replace the <<, >>, -> symbols with the proper ones]
Thank you for the very valuable contribution.
--
Regards,
James
seba...@gmail.com
Seba
dimitr...@gmail.com
Have you tested the parity? With my cable made by Eric Richlin, transmission to a PC (i.e. Hyperterminal) does not work if the parity is not set to None (i.e. odd or even), whatever the speed is set to.
Regards,
Dimitri