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Sci.Electronics.Basics -> seven segment display
There are 5 messages in this thread.
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Hello,
I am attempting to find a (multiplexing)seven segment display
driver capable of driving at least 5 7seg drivers. I have found many
but it seems they all have a synchronized serial input like SPI, but
most of them are I2C. I would imagine this is to make designing with a
uC easier, but what if I want to hook it up to my computers RS232
serial port? Do they make chips that talk Asynchronous RS232? If they
dont, is it feasible to make some sort of RS232 to I2C interface? I
have attempted coding an imaginary I2C port using my parallel port and
switching two pins trying to simulate the Data and Clock lines of an
I2C port, but my little driver doesnt seem to like it. Has anyone run
into this issue before?
Thank you for your help,
Rich
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Author: petrus bitbyterDate: 14:24 22-09-06
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<rsippken@gmail.com> schreef in bericht
news:1158942482.175305.157440@d34g2000cwd.googlegroups.com...
> Hello,
>
> I am attempting to find a (multiplexing)seven segment display
> driver capable of driving at least 5 7seg drivers. I have found many
> but it seems they all have a synchronized serial input like SPI, but
> most of them are I2C. I would imagine this is to make designing with a
> uC easier, but what if I want to hook it up to my computers RS232
> serial port? Do they make chips that talk Asynchronous RS232? If they
> dont, is it feasible to make some sort of RS232 to I2C interface? I
> have attempted coding an imaginary I2C port using my parallel port and
> switching two pins trying to simulate the Data and Clock lines of an
> I2C port, but my little driver doesnt seem to like it. Has anyone run
> into this issue before?
>
> Thank you for your help,
> Rich
>
In the days of MSDOS Philips had a simple circuit and a program to play I2C
master using the parallel port of a PC. I build one, I worked with it.
Should still be somewhere on the net although I did not find it lately on
the Philps site. Maybe it's even somewhere in my attic.
Chips that talk asynchronous RS232 are called UARTs. Still some stand alone
chips maybe available somewhere, most UARTs are found in microcontrollers
these days. Microcontrollers with I2C build in are also very common.
I ever build a RS232-I2C converter using a PIC16F73. You can't use it as it
was meant to be a slave device and you need a master. These days newer PICs
are around with both I2C master/slave and a UART on board. The PIC16F873 for
instance. Should be relatively easy to build the converter you want with it.
petrus bitbyter
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petrus bitbyter wrote:
> <rsippken@gmail.com> schreef in bericht
> news:1158942482.175305.157440@d34g2000cwd.googlegroups.com...
> > Hello,
> >
> > I am attempting to find a (multiplexing)seven segment display
> > driver capable of driving at least 5 7seg drivers. I have found many
> > but it seems they all have a synchronized serial input like SPI, but
> > most of them are I2C. I would imagine this is to make designing with a
> > uC easier, but what if I want to hook it up to my computers RS232
> > serial port? Do they make chips that talk Asynchronous RS232? If they
> > dont, is it feasible to make some sort of RS232 to I2C interface? I
> > have attempted coding an imaginary I2C port using my parallel port and
> > switching two pins trying to simulate the Data and Clock lines of an
> > I2C port, but my little driver doesnt seem to like it. Has anyone run
> > into this issue before?
> >
> > Thank you for your help,
> > Rich
> >
>
> In the days of MSDOS Philips had a simple circuit and a program to play I2C
> master using the parallel port of a PC. I build one, I worked with it.
> Should still be somewhere on the net although I did not find it lately on
> the Philps site. Maybe it's even somewhere in my attic.
>
> Chips that talk asynchronous RS232 are called UARTs. Still some stand alone
> chips maybe available somewhere, most UARTs are found in microcontrollers
> these days. Microcontrollers with I2C build in are also very common.
>
> I ever build a RS232-I2C converter using a PIC16F73. You can't use it as it
> was meant to be a slave device and you need a master. These days newer PICs
> are around with both I2C master/slave and a UART on board. The PIC16F873 for
> instance. Should be relatively easy to build the converter you want with it.
>
> petrus bitbyter
Petrus,
Thank you for the reply. Another method I tried was to "bit-bang"
my parallel port with this C++ code:
#include <iostream.h>
#include <stdlib.h>
#include <dos.h>
#include <conio.h>
#include <stdio.h>
#include <ctime>
#include <windows.h>
#include <math.h>
void start();
void stop();
void command(int i);
void senddata(int i);
void ack();
void address();
int main()
{
int w,x,y,z,t;
{
t=1436;
z=t/1000;
y=(t-z*1000)/100;
x=(t-y*100-z*1000)/10;
w=t%10;
start();
address();
command(2);
stop();
start();
address();
command(3);
stop();
start();
address();
command(5);
senddata(w);
stop();
start();
address();
command(6);
senddata(x);
stop();
start();
address();
command(7);
senddata(y);
stop();
start();
address();
command(8);
senddata(z);
stop();
}
system("PAUSE");
return 0;
}
void ack()
{
int ack=0;
_outp(0x378,0); //SCL OFF SDA OFF ACKNOWLEDGE BIT (SET BY
MAX6958)
_outp(0x378,2); //SCL ON SDA OFF ACKNOWLEDGE BIT (SET BY
MAX6958)
_outp(0x378,2); //SCL ON SDA OFF
_outp(0x378,2); //SCL ON SDA OFF ACKNOWLEDGE BIT (SET BY
MAX6958)
_outp(0x378,2); //SCL ON SDA OFF
sleep(10);
while(ack!=2)
{
ack=_inp(0x378);
}
_outp(0x378,0); //SCL OFF SDA OFF
_outp(0x378,0); //SCL OFF SDA OFF
_outp(0x378,0); //SCL OFF SDA OFF
_outp(0x378,0); //SCL OFF SDA OFF
}
void start()
{
_outp(0x378,3); //SCL ON SDA ON
_outp(0x378,3); //SCL ON SDA ON
_outp(0x378,2); //SCL ON SDA OFF START BIT
_outp(0x378,2); //SCL ON SDA OFF
_outp(0x378,0); //SCL OFF SDA OFF
_outp(0x378,0); //SCL OFF SDA OFF
_outp(0x378,0); //SCL OFF SDA OFF
_outp(0x378,0); //SCL OFF SDA OFF
}
void stop()
{
_outp(0x378,2); //SCL ON SDA OFF
_outp(0x378,2); //SCL ON SDA OFF
_outp(0x378,3); //SCL ON SDA ON STOP BIT
_outp(0x378,3); //SCL ON SDA ON
_outp(0x378,3); //SCL ON SDA ON
_outp(0x378,3); //SCL ON SDA ON STOP BIT
_outp(0x378,3); //SCL ON SDA ON
_outp(0x378,3); //SCL ON SDA ON
}
void low()
{
_outp(0x378,0); //SCL OFF SDA OFF
_outp(0x378,0); //SCL OFF SDA OFF
_outp(0x378,2); //SCL ON SDA OFF
_outp(0x378,2); //SCL ON SDA OFF
_outp(0x378,2); //SCL ON SDA OFF
_outp(0x378,2); //SCL ON SDA OFF
_outp(0x378,0); //SCL OFF SDA OFF
_outp(0x378,0); //SCL OFF SDA OFF
_outp(0x378,0); //SCL OFF SDA OFF
_outp(0x378,0); //SCL OFF SDA OFF
}
void high()
{
_outp(0x378,1); //SCL OFF SDA ON
_outp(0x378,1); //SCL OFF SDA ON
_outp(0x378,3); //SCL ON SDA ON
_outp(0x378,3); //SCL ON SDA ON
_outp(0x378,3); //SCL ON SDA ON
_outp(0x378,3); //SCL ON SDA ON
_outp(0x378,1); //SCL OFF SDA ON
_outp(0x378,1); //SCL OFF SDA ON
_outp(0x378,1); //SCL OFF SDA ON
_outp(0x378,1); //SCL OFF SDA ON
}
void address()
{
low(); high(); high(); high(); low(); low(); high(); low(); ack();
//A0 R/W
}
void senddata(int i)
{
if(i==0)
{
low(); low(); low(); low(); low(); low(); low(); low(); ack();
}
else if(i==1)
{
low(); low(); low(); low(); low(); low(); low(); high(); ack();
}
else if(i==2)
{
low(); low(); low(); low(); low(); low(); high(); low(); ack();
}
else if(i==3)
{
low(); low(); low(); low(); low(); low(); high(); high(); ack();
}
else if(i==4)
{
low(); low(); low(); low(); low(); high(); low(); low(); ack();
}
else if(i==5)
{
low(); low(); low(); low(); low(); high(); low(); high(); ack();
}
else if(i==6)
{
low(); low(); low(); low(); low(); high(); high(); low(); ack();
}
else if(i==7)
{
low(); low(); low(); low(); low(); high(); high(); high();
ack();
}
else if(i==8)
{
low(); low(); low(); low(); high(); low(); low(); low(); ack();
}
else if(i==9)
{
low(); low(); low(); low(); high(); low(); low(); high(); ack();
}
}
void command(int i)
{
if(i==1)
{
low(); low(); low(); low(); low(); low(); low(); high();
ack(); //DECODE MODE
low(); low(); low(); low(); high(); high(); high(); high();
ack();
}
else if(i==2)
{
low(); low(); low(); low(); low(); low(); high(); low();
ack();
low(); low(); low(); high(); low(); low(); low(); high();
ack(); //INTENSITY (CURRENTLY 32/64)
}
else if(i==3)
{
low(); low(); low(); low(); low(); low(); high(); high();
ack();
low(); low(); low(); low(); low(); low(); high(); high();
ack(); //SCAN LIMIT (SELECT NUMBER OF DIGITS)
}
else if(i==4)
{
low(); low(); low(); low(); low(); high(); high(); high();
ack(); //DISPLAY TEST
}
else if(i==5)
{
low(); low(); high(); low(); low(); low(); low(); low();
ack(); //DIGIT 0 LS
}
else if(i==6)
{
low(); low(); high(); low(); low(); low(); low(); high();
ack(); //DIGIT 1
}
else if(i==7)
{
low(); low(); high(); low(); low(); low(); high(); low();
ack(); //DIGIT 2
}
else if(i==8)
{
low(); low(); high(); low(); low(); low(); high(); high();
ack(); //DIGIT 4 MS
}
else
{
low(); low(); low(); low(); low(); low(); low(); low();
ack();
}
}
I am trying to interface with the MAXIM-IC MAX6958 chip. When I look at
the waveforms my code creates on an O-Scope, it appears to be correct
based of this data sheet. Perhaps I am missing a very simple I2C
concept.
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Author: petrus bitbyterDate: 18:14 22-09-06
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<rsippken@gmail.com> schreef in bericht
news:1158951036.757879.79100@d34g2000cwd.googlegroups.com...
>
> petrus bitbyter wrote:
>> <rsippken@gmail.com> schreef in bericht
>> news:1158942482.175305.157440@d34g2000cwd.googlegroups.com...
>> > Hello,
>> >
>> > I am attempting to find a (multiplexing)seven segment display
>> > driver capable of driving at least 5 7seg drivers. I have found many
>> > but it seems they all have a synchronized serial input like SPI, but
>> > most of them are I2C. I would imagine this is to make designing with a
>> > uC easier, but what if I want to hook it up to my computers RS232
>> > serial port? Do they make chips that talk Asynchronous RS232? If they
>> > dont, is it feasible to make some sort of RS232 to I2C interface? I
>> > have attempted coding an imaginary I2C port using my parallel port and
>> > switching two pins trying to simulate the Data and Clock lines of an
>> > I2C port, but my little driver doesnt seem to like it. Has anyone run
>> > into this issue before?
>> >
>> > Thank you for your help,
>> > Rich
>> >
>>
>> In the days of MSDOS Philips had a simple circuit and a program to play
>> I2C
>> master using the parallel port of a PC. I build one, I worked with it.
>> Should still be somewhere on the net although I did not find it lately on
>> the Philps site. Maybe it's even somewhere in my attic.
>>
>> Chips that talk asynchronous RS232 are called UARTs. Still some stand
>> alone
>> chips maybe available somewhere, most UARTs are found in microcontrollers
>> these days. Microcontrollers with I2C build in are also very common.
>>
>> I ever build a RS232-I2C converter using a PIC16F73. You can't use it as
>> it
>> was meant to be a slave device and you need a master. These days newer
>> PICs
>> are around with both I2C master/slave and a UART on board. The PIC16F873
>> for
>> instance. Should be relatively easy to build the converter you want with
>> it.
>>
>> petrus bitbyter
>
> Petrus,
>
> Thank you for the reply. Another method I tried was to "bit-bang"
> my parallel port with this C++ code:
>
> #include <iostream.h>
> #include <stdlib.h>
> #include <dos.h>
> #include <conio.h>
> #include <stdio.h>
> #include <ctime>
> #include <windows.h>
> #include <math.h>
>
>
> void start();
> void stop();
> void command(int i);
> void senddata(int i);
> void ack();
> void address();
>
> int main()
> {
> int w,x,y,z,t;
>
> {
> t=1436;
> z=t/1000;
> y=(t-z*1000)/100;
> x=(t-y*100-z*1000)/10;
> w=t%10;
>
>
>
>
> start();
> address();
> command(2);
> stop();
>
> start();
> address();
> command(3);
> stop();
>
> start();
> address();
> command(5);
> senddata(w);
> stop();
>
> start();
> address();
> command(6);
> senddata(x);
> stop();
>
> start();
> address();
> command(7);
> senddata(y);
> stop();
>
> start();
> address();
> command(8);
> senddata(z);
> stop();
>
>
>
> }
> system("PAUSE");
> return 0;
> }
>
>
> void ack()
> {
> int ack=0;
> _outp(0x378,0); //SCL OFF SDA OFF ACKNOWLEDGE BIT (SET BY
> MAX6958)
> _outp(0x378,2); //SCL ON SDA OFF ACKNOWLEDGE BIT (SET BY
> MAX6958)
> _outp(0x378,2); //SCL ON SDA OFF
> _outp(0x378,2); //SCL ON SDA OFF ACKNOWLEDGE BIT (SET BY
> MAX6958)
> _outp(0x378,2); //SCL ON SDA OFF
> sleep(10);
> while(ack!=2)
> {
> ack=_inp(0x378);
>
> }
>
> _outp(0x378,0); //SCL OFF SDA OFF
> _outp(0x378,0); //SCL OFF SDA OFF
> _outp(0x378,0); //SCL OFF SDA OFF
> _outp(0x378,0); //SCL OFF SDA OFF
> }
> void start()
> {
>
> _outp(0x378,3); //SCL ON SDA ON
> _outp(0x378,3); //SCL ON SDA ON
> _outp(0x378,2); //SCL ON SDA OFF START BIT
> _outp(0x378,2); //SCL ON SDA OFF
> _outp(0x378,0); //SCL OFF SDA OFF
> _outp(0x378,0); //SCL OFF SDA OFF
> _outp(0x378,0); //SCL OFF SDA OFF
> _outp(0x378,0); //SCL OFF SDA OFF
>
> }
>
> void stop()
> {
> _outp(0x378,2); //SCL ON SDA OFF
> _outp(0x378,2); //SCL ON SDA OFF
> _outp(0x378,3); //SCL ON SDA ON STOP BIT
> _outp(0x378,3); //SCL ON SDA ON
> _outp(0x378,3); //SCL ON SDA ON
> _outp(0x378,3); //SCL ON SDA ON STOP BIT
> _outp(0x378,3); //SCL ON SDA ON
> _outp(0x378,3); //SCL ON SDA ON
> }
>
> void low()
> {
> _outp(0x378,0); //SCL OFF SDA OFF
> _outp(0x378,0); //SCL OFF SDA OFF
> _outp(0x378,2); //SCL ON SDA OFF
> _outp(0x378,2); //SCL ON SDA OFF
> _outp(0x378,2); //SCL ON SDA OFF
> _outp(0x378,2); //SCL ON SDA OFF
> _outp(0x378,0); //SCL OFF SDA OFF
> _outp(0x378,0); //SCL OFF SDA OFF
> _outp(0x378,0); //SCL OFF SDA OFF
> _outp(0x378,0); //SCL OFF SDA OFF
> }
>
> void high()
> {
> _outp(0x378,1); //SCL OFF SDA ON
> _outp(0x378,1); //SCL OFF SDA ON
> _outp(0x378,3); //SCL ON SDA ON
> _outp(0x378,3); //SCL ON SDA ON
> _outp(0x378,3); //SCL ON SDA ON
> _outp(0x378,3); //SCL ON SDA ON
> _outp(0x378,1); //SCL OFF SDA ON
> _outp(0x378,1); //SCL OFF SDA ON
> _outp(0x378,1); //SCL OFF SDA ON
> _outp(0x378,1); //SCL OFF SDA ON
> }
>
> void address()
> {
> low(); high(); high(); high(); low(); low(); high(); low(); ack();
> //A0 R/W
> }
>
> void senddata(int i)
> {
> if(i==0)
> {
> low(); low(); low(); low(); low(); low(); low(); low(); ack();
> }
> else if(i==1)
> {
> low(); low(); low(); low(); low(); low(); low(); high(); ack();
> }
> else if(i==2)
> {
> low(); low(); low(); low(); low(); low(); high(); low(); ack();
> }
> else if(i==3)
> {
> low(); low(); low(); low(); low(); low(); high(); high(); ack();
> }
> else if(i==4)
> {
> low(); low(); low(); low(); low(); high(); low(); low(); ack();
> }
> else if(i==5)
> {
> low(); low(); low(); low(); low(); high(); low(); high(); ack();
> }
> else if(i==6)
> {
> low(); low(); low(); low(); low(); high(); high(); low(); ack();
> }
> else if(i==7)
> {
> low(); low(); low(); low(); low(); high(); high(); high();
> ack();
> }
> else if(i==8)
> {
> low(); low(); low(); low(); high(); low(); low(); low(); ack();
> }
> else if(i==9)
> {
> low(); low(); low(); low(); high(); low(); low(); high(); ack();
> }
>
> }
>
> void command(int i)
> {
> if(i==1)
> {
> low(); low(); low(); low(); low(); low(); low(); high();
> ack(); //DECODE MODE
> low(); low(); low(); low(); high(); high(); high(); high();
> ack();
> }
> else if(i==2)
> {
> low(); low(); low(); low(); low(); low(); high(); low();
> ack();
> low(); low(); low(); high(); low(); low(); low(); high();
> ack(); //INTENSITY (CURRENTLY 32/64)
> }
> else if(i==3)
> {
> low(); low(); low(); low(); low(); low(); high(); high();
> ack();
> low(); low(); low(); low(); low(); low(); high(); high();
> ack(); //SCAN LIMIT (SELECT NUMBER OF DIGITS)
> }
> else if(i==4)
> {
> low(); low(); low(); low(); low(); high(); high(); high();
> ack(); //DISPLAY TEST
> }
> else if(i==5)
> {
> low(); low(); high(); low(); low(); low(); low(); low();
> ack(); //DIGIT 0 LS
> }
> else if(i==6)
> {
> low(); low(); high(); low(); low(); low(); low(); high();
> ack(); //DIGIT 1
> }
> else if(i==7)
> {
> low(); low(); high(); low(); low(); low(); high(); low();
> ack(); //DIGIT 2
> }
> else if(i==8)
> {
> low(); low(); high(); low(); low(); low(); high(); high();
> ack(); //DIGIT 4 MS
> }
> else
> {
> low(); low(); low(); low(); low(); low(); low(); low();
> ack();
> }
>
> }
>
> I am trying to interface with the MAXIM-IC MAX6958 chip. When I look at
> the waveforms my code creates on an O-Scope, it appears to be correct
> based of this data sheet. Perhaps I am missing a very simple I2C
> concept.
>
Do you have enough information about I2C? The whole protocol is relatively
critical. More info on links below.
http://www.i2c-bus.org/fileadmin/ftp/i2c_bus_specification_1995.pdf
http://www.nxp.com/acrobat_download/applicationnotes/AN10216_1.pdf
Did some digging in the attic but did not found the program mentioned.
petrus bitbyter
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Author: john jardineDate: 20:09 22-09-06
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<rsippken@gmail.com> wrote in message
news:1158942482.175305.157440@d34g2000cwd.googlegroups.com...
> Hello,
>
> I am attempting to find a (multiplexing)seven segment display
> driver capable of driving at least 5 7seg drivers. I have found many
> but it seems they all have a synchronized serial input like SPI, but
> most of them are I2C. I would imagine this is to make designing with a
> uC easier, but what if I want to hook it up to my computers RS232
> serial port? Do they make chips that talk Asynchronous RS232? If they
> dont, is it feasible to make some sort of RS232 to I2C interface? I
> have attempted coding an imaginary I2C port using my parallel port and
> switching two pins trying to simulate the Data and Clock lines of an
> I2C port, but my little driver doesnt seem to like it. Has anyone run
> into this issue before?
>
> Thank you for your help,
> Rich
>
RS232 would be a nightmare. LPT is the way to go, either as straightforward
clocked serial bits or the more convoluted i2c.
You need to build a small adapter to run i2c lines.
http://www.armory.com/~rstevew/Public/LPT/Lpt_i2c.gif
Works fine. There's also ready made prog's out there, to allow easy use of
the i2c commands.
The one I use is only about 40 lines long, (but in Basic).
john
--
Posted via a free Usenet account from http://www.teranews.com
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