9600 Baud Rate Not Work in Easy8051B

[arponcedeleon]

Hi,

I have the development board Easy8051B, and the compiler mikroPascal for 8051, and I want use UART and the problem is here:
With the example of mikroPascal -> this work with UART1_Init(4800); and I have perfect result is ok. When I change the baud rate to 9600 really dont work, I read bad bytes (note: if I change the value baud in my source code I change the baud rate in my RS232Terminal).

The microcontroller is a AT89S8253
using the oscilator 10MHz
Default pin RS232 are RX=P3.0 and TX=P3.1

I use also the project example Software UART Library and dont work too.

thanks

Adrian

[tihomir.losic]

The microcontroller is a AT89S8253
using the oscilator 10MHz
Default pin RS232 are RX=P3.0 and TX=P3.1

Hello,

you need to select following option in mikroPascal:
x2 - optional parameter for certain ATMEL MCU's that feature x2 mode, which speeds up the MCU by 2 (6 oscillator periods per instruction, instead of 12).

x2.PNG (9.29 KiB) Viewed 4737 times

On following link, you can find out more about baud rate for ATMEL 8051 microcontrollers:
http://www.atmel.com/dyn/resources/prod ... oc4316.pdf
X2 bit is located in the CKCON register.
In X2 mode, FOSC=FXTAL. In standard mode, FOSC=FXTAL/2.

Best regards,

Losic Tihomir

[arponcedeleon]

Thanks,
Just now I go to test that mode,

If I use a 11.0592 MHz?

[tihomir.losic]

Hello,

please, try with 16MHz...

Best regards,

Losic Tihomir

[arponcedeleon]

Thanks,

The change with Oscilator 10MHz and cheking the option x2 work perfectly, I can send and receibe byte on PORT COM RS232 9600Baud

But when I try with 11.0952MHz this option dont work,

I have a hardware made like a display 7segment (8 display) and need read array of bytes by serial port in 9600,8,N1 and It hardware have a MCU AT89C52 with external oscilator of 11.0952 MHz, for the moment I change the MCU by AT89S8253 all the pin are similar, I change this MCU why the 8051Flash Programmer dont have the AT89C52 and cant programing.

must be exist some way to compile my program with oscilator 11.0952MHz,

thanks you