68300

Hello List,

I need some advise on setting up a half-duplex RS485 channel using 
both the QSM's Serial Communication Interface and also the TPU's UART 
function.  I have two serial ports on my circuit board, and I have 
already set up hardware for both.  My driver chips have both Drive 
Enable and Receive Enable pins, which I have tied together.  I am 
using PC6 to control the DE/RE line for the QSM's SCI port and PC5 to 
control the one for the TPU port.

My question is this:  Is there a status bit or some flagging 
mechanism I can use to say that when the 68376 is done transmitting a 
message, I can now safely change the state of the DE/RE bit and 
prepare to receive data?  I have a concern about when a flag would be 
set compared to when the last bit in the data is shifted onto the bus.

I am hoping to avoid having to use any kind of delay timer to switch 
from TX->RX or RX->TX.

Thanks,
Jim