Communicate with PC at baud rate :115200 bps

[Archangel]

oky I have these things :
1- max232 converter
2- 4MHZ or 8MHZ crystal
3- PIC16F877A or PIC18f452 or PIC4220

I make a programm and put the values accoding to formula baud=fosc/(16(x+1)) or baud=fosc(64/(x+1))

but the data I recived from pic at pc is a strange data not know

"4MHZ or 8MHZ crystal" 4mhz too slow 8mhz probably too slow
go get this from mister e http://www.mister-e.org/pages/picmulticalcpag.html
using Mister_e's calculator set for 8mhz we get these settings:

RCSTA = $90 ' Enable serial port & continuous receive
TXSTA = $24 ' Enable transmit, BRGH = 1
SPBRG = 16 ' 115200 Baud @ 8MHz, 2.12%
SPBRGH = 0
BAUDCON.3 = 1 ' Enable 16 bit baudrate generator

You may need to slow the character pacing a bit. DEFINE CHAR_PACING 1000

[BrianT]

By default, PIC ports have their OFF or IDLE condition as zero volts. RS-232 however defines the IDLE or steady mark to be negative volts at the 25 pin connector. This means the idle condition between the PIC and the MAX232 chip must be HIGH or positive - the reverse of what you might first think.

An asynchronous character begins when the receiving device detects the transition from the steady MARK to a SPACE bit. BUT, if you did nothing to the Txoutput pin before that character started, then the line had been in the space condition for some time. i.e. the start bit goes missing and so the character is corrupted.

Try this.

HIGH Txpin 'sets the RS-232 connector pin to negative = Mark = Idle
pause 1 ' lest the line settle and the remote device see the mark condition
Serout/hserout/serout21 pin, rate, data 'the message now starts with a guaranteed start bit.

HTH
BrianT

[iugmoh]

SPBRGH = 0
BAUDCON.3 = 1 ' Enable 16 bit baudrate generator

Oky with PIC16f877a this give me an error because theses registers are not exist

[skimask]

Oky with PIC16f877a this give me an error because theses registers are not exist

And a quick look at the '877A datasheet, Table 10-3, would tell you that getting 115,200 baud out of 4 or 8 Mhz isn't going to happen, unless you can somehow magically get a divisor of 1.5 stuff into that byte value.
You need more crystals in your toolbox.
Actually, what you need is more variety...

[iugmoh]

ok what is the suitable PIC IC needed with crystal to achive this problem

[skimask]

ok what is the suitable PIC IC needed with crystal to achive this problem

FASTER...that's all...FASTER! Read the Tables and you'll see what I mean.
A serial link can tolerate X amount of error. So, find the combination of oscillator speeds and serial communication speeds that works for your unique situation.
I can't help you much more than that...I don't think anybody can...until you do some reading and comprehending the information involved.
The 16F877A will run at 20Mhz (possibly a bit faster), the 18Fxxxx series will run at 40Mhz (55Mhz in my experience, but not recommended for reliability). Either of those chips that you have been relating to in your threads will work just fine.
You need more crystals! More oscillators! More freq! More cycles per second! More HERTZ! More variances of direct current per unit of time!
That's all!