Re: TI-H: Serial port


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Re: TI-H: Serial port




David Knaack wrote:
> 
> From: Antonio Larrosa <antlarr@arrakis.es>
> >I'll use (I am using) linux, and already know how to send bytes through
> >the port, but I've read the communication goes bit per bit.
> >
> >Now, how can I handle directly what is being send through each pin in
> >the serial port ?
> >Anybody knows where can I find such information ?
> 
> The data is sent using the signaling wires (CTS, DTR, etc), you just
> set and read states like that, you never actually send bytes over the
> serial wires.
> 

Thanks for the info, now I understand how can I use a serial port to send
bit per bit instead of a whole byte at a time.
Sorry for not answering before, I've been busy searching and reading info
about the serial port (in some books and Ralf Brown interrupt/port/whatever
hardwareyouhave lists )

Now, I have this list of ports, could you please tell me which one has
the status I have to read and write ?

02F8    w       transmitter holding register
02F8    r       receiver buffer register
        r/w     divisor latch, low byte   when DLAB=1
02F9    r/w     divisor latch, high byte  when DLAB=1
        r/w     interrupt enable register when DLAB=0
02FA    r       interrupt identification register
02FB    r/w     line control register
02FC    r/w     modem control register
02FD    r       line status register
02FF    r/w     scratch register   

I supposed it's 0x2FD, but it's only read, so in case it is, I should
read from one and write to another port, isn't it ? Also, I've been
thinking, to use the serial port reading and writing status, I should
set the pins 3,4 and 7 to a given voltage so that pins 6 and 8 transmit
the same values as the calculator ends, isn't it ?

Also, I've tried to make an app that makes a loop reading every port
(not every port of course :-) just those 8 ones), while I used the calc
to "Send Product Code" and send a variable (in the Var-Link menu), but
this application always read the same values.

I know there must be a "communication" to transmit a bit, but at least, 
if the calculator starts sending something, at least a bit should change
in one of the ports, but it doesn't.

> I haven't the slightest clue how you would do that in Linux, but I'd guess
> its fairly straightforward.
> 

The communication with the ports is the same as in dos, I just need to be
root to send and receive data through a port (that is, to use the asm "in"
and "out" opcodes), but for now, I can live running this app setuid. 
Anyway, I wasn't asking for already done sources, but for help on how
to use the serial port (btw, is there any application available which
releases its source code ? :-) )

Greetings,

--
Antonio Larrosa Jimenez
Student of Mathematics
antlarr@arrakis.es        larrosa@kde.org
http://www.arrakis.es/~rlarrosa
Klein bottles for rent -- inquire within.




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