hi-speed UART

[oe]

Posted on September 09, 2009 at 13:57

hi-speed UART

[oe]

Posted on May 17, 2011 at 13:23

I need a hi-spped UART, running at 250kbaud. Do anyone have any suggestions?

I suppose it would be possible to alter the X-tal and make the CPU run at a frequency that can be devided to get the correct baudrate. [ This message was edited by: oe on 09-09-2009 14:52 ]

[picguy]

Posted on May 17, 2011 at 13:23

STM32 UARTs use the divide by 16 approach. Thus with a 72 MHz processor clock (I used an 8 MHz xtal) UART1 can run at 4.5 Mbaud. (About 25% of what I wanted. But that’s not your issue.) You need a 16*250 KHz = 4 MHz input to the UART.

Unless you have power issues assume you are running with a 72 MHz processor clock. Look at the clock tree in general and UART1 frequency source in particular. Get at close as you can to 4 MHz. If you can not get close enough you may need to use another xtal. But check with your hardware people. Non-standard frequencies may be hard to obtain and therefore expensive.