Hi, We are using embOS and emFile on the following setup, 1. emFile 2. embOS 3. LPC1787 - NXP ARM-M3 4. SDCard (1GB - Industrial) via LPC Media Card Interface (MCI) 5. x5 USARTs for serial communication between other devices. We have successfully run the x5 USARTs for quite a while now. The RX is "interrupt" driven and the TX is "DMA" driven on all USARTS. We had to resort to converting the interrupts to "zero latency" interrupts as described in the embOS manual Chapter 12. Recently we added emF…