LPC1549 UART RS485 Auto Direction control

lpcware — Wed, 15 Jun 2016 17:10:32 GMT

Content originally posted in LPCWare by Carl-CircuitWorx on Fri Jun 19 11:25:19 MST 2015
Hi,

Have set up DMA on UART1 to TX an array and configured RS485 control of the RTS line by setting the bits UART_OETA, UART_OESEL, UART_OEPOL
It works but I can see the direction line blipping between each byte even with the OETA bit set which should delay a change of the direction line for the width of 1 character.

Have attached an screen cap of the trace from a logic analyser, top trace is with out OETA set, bottom is with.

I can't see any other settings to change, I could use the pin in gpio mode at the start of TX and switch to RTS once the DMA IRQ Fires I suppose.

Any ideas?

[img]http://i.imgur.com/yj0uzCG.png[/img]

topic LPC1549 UART RS485 Auto Direction control in LPC Microcontrollers

LPC1549 UART RS485 Auto Direction control