LPC178x: UART 38400bps with 12MHz IRC

[giusloq]

I need to create a RS485/UART communication link between LPC178X and SAMD20 MCU. The communication should be 38400bps.

The clock on SAMD20 is based on an external 32.768kHz crystal (XOSC32K) and DFLL in closed loop mode.

I'm wondering if it is possible to clock LPC178X with internal IRC 12MHz oscillator. The datasheet reports a precision of 1% (11.88-12.12MHz) over all the voltages and temperatures. It seems sufficient for UART communication that usually needs a maximum of 2% error.

[Habib_MS]

Hello @giusloq,
I understand that you would use the IRC as core source clock, it is possible, as mentioned in the chapter 1.2 called "Features", as shown in the next image:

Habib_MS_0-1744146716879.png

Also, if you experience any issue do not hesitate to let me know
BR
Habib.