Zilog Z16C30 - Manual (Page 94)

5-27
Z16C30 USC ®
U SER ' S M ANUAL Z ILOG
UM97USC0100
Figure 5-10. How a USC Channel Provides the “Queued” Status Bits in the RCSR
Start for RxBound,
Abort/PE, or RxOver:
Has the (MSByte
of the) RCSR been
read since then?
Did the last read
from the RDR have
RxBound=1?
Provide the saved
status of the
RxBound character
What's the
corresponding IA
bit in the RICR?
Provide the state of a latch
that's set when a character
with this condition becomes
the oldest in the RxFIFO
(or the 2nd-oldest with
WordStatus=1), and is cleared
when SW writes a 1 to this bit
Start for ShortFrame/
CVType or CRCE/FE:
1
0
Yes No
How many
characters are in
the RxFIFO??
(The bit is not
defined!)
What's the
WordStatus bit
(RICR3)?
No
Yes
Provide the inclusive
OR of the status of the
two oldest characters
in the RxFIFO
Provide the status of
the oldest character
in the RxFIFO
None
Two or
more
One
0
1
UM009402-0201