max232 and pic16f877a

E

Eng.Abbasi

New Member

• Sep 21, 2006

• #1

hello all

im using USART module in pic16f877a to transfer data to the serial port of my pc . first do i have to use max232 to make the preparation for the PC port or not,
second i used value d'31' in the BRGH register to set baud-rate 9600 was it wrong?

and thanx for all

 

Papabravo

Well-Known Member

• Sep 21, 2006

• #2

The serial port of a PC does use RS-232 levels so I would say that you need the transceiver. The value in the BRGH register depends on the frequency of operation of the PIC, so the value you used may or may not be correct. What does the datasheet say?

 

E

Eng.Abbasi

New Member

• Sep 21, 2006

• #3

thnx Mr. the pic16f877a and the oscillater is 20Mhz

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• Sep 22, 2006

• #4

Check my tutorials, the last of the RS232 ones uses the hardware USART at 9600 baud with a 20MHz crystal.

 

E

Eng.Abbasi

New Member

• Sep 25, 2006

• #5

ok it was written in the data sheet but my mistake is the max232
129 at high
31 at low

 

Mike - K8LH

Well-Known Member

• Sep 25, 2006

• #6

You can download an Excel 2000 SPBRG Calculator spreadsheet from this thread on Forum Microchip; **broken link removed**

There's also a single-file stand-alone application (screen shot below) you can download from that same thread.

Regards, Mike

**broken link removed**

 

Last edited: Sep 25, 2006