From: Billalabeitia, Jose Carlos (IndSys, GEPM)
<jc.billalabeitia@in...> - 2001-05-22 16:26:42
I am working with a custom 860T CPU, using PPCboot as a basis and
I need to pull high an output pin at the same time that the UART begins to
send a character, and push it down when the character has been sent
fisically through the line. Is there any way, by software, of knowing at
time exactly the UART (or in general an SCC or SMC) begins to fisically
transmit and when finishes exactly the transmission of the last bit of the
frame, in order to activate/desactivate at these precise instants a digital
I have been trying to syncronize a digital output with the buffer descriptor
flag READY, but checked with the scope these signals are not syncronized
as wanted. My thinking is that flag READY becomes clear once the
character is in the shift register but has not been sent yet. Is it correct?
I have also seen in the scope that there is some time between the instant
I put high the digital output and the instant the flag READY is set, even
though they are contiguous in the code. I tried with the asm sentences
"eieio", "isync" and/or "sync". Why?
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