AT89C55 and PC communication question

[gah_wah]

Dear all,

I have two question about the AT89C55 serial communication, hope anyone could help?
1) I would like to communication the AT89C55 to a PC.
2) I also would like to communicate the AT89C55 to a Nokia 6150 mobile.

Can I directly communication the AT89C55 TX/RX to these two equipments?

Thanks
Best Regards,
gah wah

 

[SphinX]

Salam,

There is built-in uart in AT89C55.
Read datasheet to learn how to set the baudrate
Sending or Receiving is very simple using SBUF register.

Here is C code to setup the uart as 9600-N-8-1, Use 11.0592 Crystal
To change the baud rate look to the datasheet
The baudrate depend on the rate of overflow of timer1

  SCON = 0x52; // 8-bit UART mode
  TMOD = 0x20; // timer 1 mode 2 auto reload
  TH1= 0xfd; // 9600 8n1
  TR1 = 1; // run timer1

No, You can send or receive directly to PC.
You need level shifter like MAX232, Google it.
Or you can just two transistors instead of MAX232.

All MAX232 is doing is convert TTL signals from AT89 to RS232(+-12V) signals and the oppssite.

using MAX232
**broken link removed**

Using Transistors
**broken link removed**

Now Bye, i have to eat something
SphinX