burning issue with LPC11U68

[Guy_mego]

Hi All,

I'm using LPC11U68, I've added some printing with UART to code. After I burned the program to the board at the first UART command I don't see the full buffer transmitted the terminal for example: "ch" is printed instead of "checking". 
The odd thing is when I burned the program on another computer everything works fine, and on a third computer again the some issue as in my computer.
I even try to reduce the buadrate to 9600 and that didn't solve the issue. In addition I even tried on another board but same issue.
Someone has an advise how to solve this issue.

Thanks in advance.

[xiangjun_rong · Accepted solution]

Hi,

I think the uart clock source inaccuracy leads the problem.

As the following figure for the clock source of LPC51U68, the watchdog oscillator clock frequency is not accurate, I do not think it can be the clock source of uart0. The IRC clock frequency accuracy is +/-1%, I think it is okay for low baudrate. The external 32KHz RTC clock frequency is the most accurate, I suggest you use it as uart clock source.

Hope it can help you

BR

XiangJun Rong