[En-Nut-Discussion] DE485 signal can not switch to high

[Joseph Chao]

Hi,

I am using the Ethernut 2 board. I tried to use UART1 as RS485.
I found that on my ethernut board the PD4/5 can not switch to high state.
The DE485 signal is 5Volts when I detach the SP483ECN chip from PCB 
but drop to less than 1Volts while the SP483ECN is solder back.
I had tried to replace the SP483ECN with a new one and with no luck.
Is this a design bug or a bad PCB problem?

Regards,

Joseph