Reply by Alexey Londkevich●November 19, 20042004-11-19
Thanx, I will to study this site
On Friday 19 of November 2004 22:39, bart homerson wrote: > If you are going to use the MAX 232, then you will
need to order some
> capacitors too. There are RS232 chips that do not require them; the
MAX232
> was the first chip that came to my mind. I would suggest that you look
> through the data sheets of the various chips before you actually make a
> decision. Digikey, http://www.digikey.com, has 1284 different RS232
> devices they also usually have a good number of data sheets for the
chips
> they stock. Good luck.
>
> LF
>
> Alexey Londkevich <> wrote:
> Thanx, people for explainig and links.
> Will to try MAX 232
>
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Reply by bart homerson●November 19, 20042004-11-19
If you are going to use the MAX 232, then you will need to order some
capacitors too. There are RS232 chips that do not require them; the MAX232 was
the first chip that came to my mind. I would suggest that you look through the
data sheets of the various chips before you actually make a decision. Digikey,
http://www.digikey.com, has 1284 different RS232 devices they also usually have
a good number of data sheets for the chips they stock. Good luck.
LF
Alexey Londkevich <> wrote:
Thanx, people for explainig and links.
Will to try MAX 232
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Reply by bart homerson●November 19, 20042004-11-19
lol
LF
Scott Grodevant <> wrote:
Hi all and LF,
Thanks, my memory must be slipping too.
Scott
bart homerson wrote:
Hello scott,
Actually, the standard says that the voltage can be between +25 and -25.
We're both incorrect. Thanks for making me look it up, my memory often
fails me.
Signal State Voltage Assignments - Voltages of -3v to -25v with respect to
signal ground (pin 7) are considered logic '1' (the marking
condition), whereas voltages of +3v to +25v are considered logic '0'
(the spacing condition). The range of voltages between -3v and +3v is considered
a transition region for which a signal state is not assigned.
I commonly see -13V, but rarely see anything over +5V on the oscilloscope with
my configuration.
LF
Scott Grodevant wrote:
Hi all and LF,
You are close, but the RS-232 signaling levels are -15 to -5 (low state) and +5
to +15 for a high.
Scott
bart homerson wrote:
Hello,
You must use a Rs-232 transciver chip such as the MAX232. What this chip does is
it translates the voltages from the RX side of the RS232 protocol into
Logic-level (+5V) for the MCU to understand. It then translates the TX pin
voltage from logic-level to the necessary -13 to 0 voltage level to match the
RS232 protocol. It's a bit confusing, but once you get it, you wont forget
it. I suggest doing a Google search for "RS-232 protocol" you will
find a bunch of information.
I hope this answer was along the lines of what you are looking for. RS-232 is a
wonderful protocol with a lot of potential. Take care.
LF
Alexey Londkevich wrote:
Hello, all.
I am beginner in 68hc11 progamming.
I must make some changes for same program.
I want to write small debug program for debugging through serial connection.
I connect PC directly to 68hc11. (Ground -ground, td-rd, rd-td).
I trying send chars from 68hc11 to PS. It work.
But I can not send char from PC.
What do I wrongly?
Perhaps it is no right - directly connection?
---------------------------------
Yahoo! Groups Links
To
---------------------------------
Reply by Alexey Londkevich●November 19, 20042004-11-19
Thanx, people for explainig and links.
Will to try MAX 232
Reply by Scott Grodevant●November 19, 20042004-11-19
Hi all and LF,
Thanks, my memory must be slipping too.
Scott
bart homerson <> wrote:
Hello scott,
Actually, the standard says that the voltage can be between +25 and -25.
We're both incorrect. Thanks for making me look it up, my memory often
fails me.
Signal State Voltage Assignments - Voltages of -3v to -25v with respect to
signal ground (pin 7) are considered logic '1' (the marking
condition), whereas voltages of +3v to +25v are considered logic '0'
(the spacing condition). The range of voltages between -3v and +3v is considered
a transition region for which a signal state is not assigned.
I commonly see -13V, but rarely see anything over +5V on the oscilloscope with
my configuration.
LF
Scott Grodevant wrote:
Hi all and LF,
You are close, but the RS-232 signaling levels are -15 to -5 (low state) and +5
to +15 for a high.
Scott
bart homerson wrote:
Hello,
You must use a Rs-232 transciver chip such as the MAX232. What this chip does is
it translates the voltages from the RX side of the RS232 protocol into
Logic-level (+5V) for the MCU to understand. It then translates the TX pin
voltage from logic-level to the necessary -13 to 0 voltage level to match the
RS232 protocol. It's a bit confusing, but once you get it, you wont forget
it. I suggest doing a Google search for "RS-232 protocol" you will
find a bunch of information.
I hope this answer was along the lines of what you are looking for. RS-232 is a
wonderful protocol with a lot of potential. Take care.
LF
Alexey Londkevich wrote:
Hello, all.
I am beginner in 68hc11 progamming.
I must make some changes for same program.
I want to write small debug program for debugging through serial connection.
I connect PC directly to 68hc11. (Ground -ground, td-rd, rd-td).
I trying send chars from 68hc11 to PS. It work.
But I can not send char from PC.
What do I wrongly?
Perhaps it is no right - directly connection?
---------------------------------
Yahoo! Groups Links
To
---------------------------------
Yahoo! Groups Links
---------------------------------
Yahoo! Groups Links
---------------------------------
Yahoo! Groups Links
---------------------------------
Reply by bart homerson●November 19, 20042004-11-19
Hello scott,
Actually, the standard says that the voltage can be between +25 and -25.
We're both incorrect. Thanks for making me look it up, my memory often
fails me.
Signal State Voltage Assignments - Voltages of -3v to -25v with respect to
signal ground (pin 7) are considered logic '1' (the marking
condition), whereas voltages of +3v to +25v are considered logic '0'
(the spacing condition). The range of voltages between -3v and +3v is considered
a transition region for which a signal state is not assigned.
I commonly see -13V, but rarely see anything over +5V on the oscilloscope with
my configuration.
LF
Scott Grodevant <> wrote:
Hi all and LF,
You are close, but the RS-232 signaling levels are -15 to -5 (low state) and +5
to +15 for a high.
Scott
bart homerson wrote:
Hello,
You must use a Rs-232 transciver chip such as the MAX232. What this chip does is
it translates the voltages from the RX side of the RS232 protocol into
Logic-level (+5V) for the MCU to understand. It then translates the TX pin
voltage from logic-level to the necessary -13 to 0 voltage level to match the
RS232 protocol. It's a bit confusing, but once you get it, you wont forget
it. I suggest doing a Google search for "RS-232 protocol" you will
find a bunch of information.
I hope this answer was along the lines of what you are looking for. RS-232 is a
wonderful protocol with a lot of potential. Take care.
LF
Alexey Londkevich wrote:
Hello, all.
I am beginner in 68hc11 progamming.
I must make some changes for same program.
I want to write small debug program for debugging through serial connection.
I connect PC directly to 68hc11. (Ground -ground, td-rd, rd-td).
I trying send chars from 68hc11 to PS. It work.
But I can not send char from PC.
What do I wrongly?
Perhaps it is no right - directly connection?
---------------------------------
Yahoo! Groups Links
To
---------------------------------
Yahoo! Groups Links
---------------------------------
Yahoo! Groups Links
---------------------------------
Reply by Scott Grodevant●November 19, 20042004-11-19
Hi all and LF,
You are close, but the RS-232 signaling levels are -15 to -5 (low state) and +5
to +15 for a high.
Scott
bart homerson <> wrote:
Hello,
You must use a Rs-232 transciver chip such as the MAX232. What this chip does is
it translates the voltages from the RX side of the RS232 protocol into
Logic-level (+5V) for the MCU to understand. It then translates the TX pin
voltage from logic-level to the necessary -13 to 0 voltage level to match the
RS232 protocol. It's a bit confusing, but once you get it, you wont forget
it. I suggest doing a Google search for "RS-232 protocol" you will
find a bunch of information.
I hope this answer was along the lines of what you are looking for. RS-232 is a
wonderful protocol with a lot of potential. Take care.
LF
Alexey Londkevich wrote:
Hello, all.
I am beginner in 68hc11 progamming.
I must make some changes for same program.
I want to write small debug program for debugging through serial connection.
I connect PC directly to 68hc11. (Ground -ground, td-rd, rd-td).
I trying send chars from 68hc11 to PS. It work.
But I can not send char from PC.
What do I wrongly?
Perhaps it is no right - directly connection?
---------------------------------
Yahoo! Groups Links
To
---------------------------------
Yahoo! Groups Links
---------------------------------
Reply by bart homerson●November 18, 20042004-11-18
Hello,
You must use a Rs-232 transciver chip such as the MAX232. What this chip does is
it translates the voltages from the RX side of the RS232 protocol into
Logic-level (+5V) for the MCU to understand. It then translates the TX pin
voltage from logic-level to the necessary -13 to 0 voltage level to match the
RS232 protocol. It's a bit confusing, but once you get it, you wont forget
it. I suggest doing a Google search for "RS-232 protocol" you will
find a bunch of information.
I hope this answer was along the lines of what you are looking for. RS-232 is a
wonderful protocol with a lot of potential. Take care.
LF
Alexey Londkevich <> wrote:
Hello, all.
I am beginner in 68hc11 progamming.
I must make some changes for same program.
I want to write small debug program for debugging through serial connection.
I connect PC directly to 68hc11. (Ground -ground, td-rd, rd-td).
I trying send chars from 68hc11 to PS. It work.
But I can not send char from PC.
What do I wrongly?
Perhaps it is no right - directly connection?
---------------------------------
Yahoo! Groups Links
To
---------------------------------
Reply by quyenqtran●November 18, 20042004-11-18
You just can't connect directly to the PC from the HC11. You need to
go thru the RS232. You also need a pull up resistor for the TxD pin
of the HC11. What I usually do is I also used a Sub-D9 connector to
connect to the Serial port of the PC.
-Quyen
--- In , Alexey Londkevich <lond@u...> wrote: > Hello, all.
>
> I am beginner in 68hc11 progamming.
> I must make some changes for same program.
> I want to write small debug program for debugging through serial connection. > I connect PC directly to 68hc11. (Ground -ground,
td-rd, rd-td).
> I trying send chars from 68hc11 to PS. It work.
> But I can not send char from PC.
> What do I wrongly?
> Perhaps it is no right - directly connection?
Reply by Alexey Londkevich●November 18, 20042004-11-18
Hello, all.
I am beginner in 68hc11 progamming.
I must make some changes for same program.
I want to write small debug program for debugging through serial connection.
I connect PC directly to 68hc11. (Ground -ground, td-rd, rd-td).
I trying send chars from 68hc11 to PS. It work.
But I can not send char from PC.
What do I wrongly?
Perhaps it is no right - directly connection?