Computer COM port & microcontroller COM port ??

If I understood, you try to send data from a 89S51 to your target device?
You should check, if the 89S51 is sending (for example connect it to a PC with a terminal programm like Hyperterminal or Docklight, check with a scope).
For RS232 debugging I always use Docklight. There is a free eva-version on the web.

If I understood, you try to send data from a 89S51 to your target device?
You should check, if the 89S51 is sending (for example connect it to a PC with a terminal programm like Hyperterminal or Docklight, check with a scope).
For RS232 debugging I always use Docklight. There is a free eva-version on the web.

Hi All,

Yes Ulf Saß u r correct.I want to send data from mic. to my device.In C51 i have configured as

SCON=0x50;
TMOD |=0x20;
TH1=0xFD;
TR1=1;
TI=1;

for 9600-N-8-1 at 12MHz.

My device communicate only on this setting - 9600 baud with NOPARITY 8 bit data and ONESTOPBIT.

I have checked with Hyperterminal it is ok.I get the data on hyperterminal.
When i send data from computer using VC++ prog. the microshows it correctly.But i can't read from micro. using same VC++ prog. to read.
what might be the problem ?

more after u r reply.....
rutu

Do You have correct HW? ->MAX323...

"But i can't read from micro. using same VC++ prog. to read.
what might be the problem ?"

its ur vc++ prog u nd 2 go 2 a vc++ prog forum

its ur vc++ prog u nd 2 go 2 a vc++ prog forum

Stefan,

You have not grasped the idea behind SMS. What you wrote took me only 10 seconds to decode, had it been true SMS it should have taken at least 1 munute.

Erik

Hi,

SCON=0x50;
TMOD |=0x20;
TH1=0xFD;
TR1=1;
TI=1;



Is these values correct for 9600-N-8-1 at 12MHz with Atmel 89S51 ? if not plz let me know the correct values.

Rutu

"Is these values correct for 9600-N-8-1 at 12MHz with Atmel 89S51 ? if not plz let me know the correct values."

According to Keil's baudrate calculator you can't do 9600 baud with timer 1 at 12MHz.

According to Keil's baudrate calculator you can't do 9600 baud with timer 1 at 12MHz.
While, you, indeed, can do it relatively precise with timer 2 - Why, Oh Why, does so many use these silly non-UART frequencies for their crystals? I honestly believe that 11.0592 is the most sold frequency, so it can not be a matter of avialability. If the original poster has taken a glance at Atmels s51 appnotes re UART, he would have seen that all specify 11.0592 crystal.

Oh well, it is probably too much to ask that someone that is too lazy to spell the words out and instead writes stupid SMS would read something.

Erik

"If the original poster has taken a glance at Atmels s51 appnotes"

Maybe he can only understand SMS?

Hi,

I checked the baudrate calculater and accordingly configured also i replaced the crystal with 11.0592, even then i m not getting the rs232 communication at 9600.
I tried activating the SMOD, even then no use.

Have anyone faced similar problem.

Rutu

Earlier in this thread you said:

"I have checked with Hyperterminal it is ok.I get the data on hyperterminal.
When i send data from computer using VC++ prog. the microshows it correctly.But i can't read from micro. using same VC++ prog. to read.
what might be the problem ?"

Summarising this we get:

1) Hyperterminal to 8051 ok
2) 8051 to hyperterminal ok
3) VC to 8051 ok
4) 8051 to VC NOT ok

Which pretty much indicates the problem is with your VC program.

may be vc receiver is not ok ?
jane

ts ur vc++ prog u nd 2 go 2 a vc++ prog forum

Wow. I'm at a loss for words.

Hi,

Individual connection is working fine.But not in between the microcontroller and the module.

I suspect that when i put 0 "zero" the microcontroller just skips it.Because i don't see anything for 0 in hyperterminal.

can this be a problem.

rutu

Hey,

I was just looking at threads on the forum when i came across a thread saying that, when we output 0x0A on RSR232 it actually outputs /r/n means 0x0D,0x0A.

My last output on the RSR232 is 0x0A.Which is end of packet.Can this be the reason for communication failer.

Rutu.

I was just looking at threads on the forum when i came across a thread saying that, when we output 0x0A on RSR232 it actually outputs /r/n means 0x0D,0x0A.

Have you written your own putchar function?

Jon