UART & USB Run Together

sg · ‎2005-12-27

Posted on December 28, 2005 at 03:06

sg · ‎2011-05-17

Posted on May 17, 2011 at 12:09

Hi,

I am new Firmware programmer. I gone through the UPSD3234A's Datasheet, it said the USB must run on 12, 24, 36MHz for MCU. I was wonder how am i able to have UART0, and USB together on a single design and run. because with 12, 24, 36MHz, i cannot get my desired baudrate, eg, 9600, 19200.

Please Advise.

wek2 · ‎2011-05-17

Posted on May 17, 2011 at 12:09

Using Timer2 as baudrate generator, 9600Baud is possible with 12MHz crystal with negligible (0.16%) error; similarly 19200Baud with 24MHz crystal.

A good tool for baudrate calculation is at the Keil pages:

http://www.keil.com/c51/baudrate.asp

Jan Waclawek

sg · ‎2011-05-17

Posted on May 17, 2011 at 12:09

THANKS A LOT. I TRIED ON IT, IT DOES HAVE SOME SMALL PERCENTAGE OF FAULTY ON 9600 BAUDRATE. ANYWAY, I GUESS I STILL STICK ON UART DESIGN.

tHANKS.