Content originally posted in LPCWare by MarcVonWindscooting on Sat Jan 25 07:07:49 MST 2014
I'm not working with LPCopen but I do work with LPC800 devices.
You have 2 clock dividers for UART. One found in SYSCON (UARTCLKDIV = 1..255) for all UARTS and one for each UART (1..65536)
Also the fractional divider is shared amoung all UARTs. Look into the LPC800 User Manual, chapter 15.
You probably need the fractional generator to generate 115200bd. You use the biggest possible divider for UARTCLKDIV (e.g. 6 if running at 12MHz for example). Then one UART runs with 115200, the other can run at a frequency 115200 / n, where n is integral and in the range of 1..65536. Decide yourself, if n = 192 does the trick ;-)
And of course, yes, the ROM-API can handle that, because YOU have to dispatch the correct ISR and it's nobody else than YOU who calls the ROM-API and there's no such thing as a 'close()' for ROM-UART structure.