Zilog Z16C30 - Manual (Page 194)

A-2
Z16C30 USC ®
U SER ' S M ANUAL
UM97USC0100
Z ILOG
June 1993 Changes
1. HDLC/SDLC Abort status can be queued with re-
ceived characters (p. 5-33).
2. Receive Data and Status (RxBound) interrupts are
delayed so that the RCC FIFO status is correct at the
time of such an interrupt (p. 5-38).
3. The RCC residual value in 32-bit Receive Status Blocks
is taken from the 4-deep RCC FIFO rather than the
singular Receive Count Holding Register (RCHR),
thus improving the reliability of frame length reporting
in RSBs (pp. 5-38, 5-42).
4. The RCC FIFO overflow status bit is included in Re-
ceive Status Blocks to indicate the validity of the RCC
residual noted in the previous point (p. 5-42) .
5. A new Purge Rx command is added, that clears both
the RxFIFO and RCC FIFO (p. 5-45).
6. Improved synchronization and interlocking between
the serial clock and bus transactions have eliminated
incorrect FIFO status and Receive DMA requesting
leading to “extra bytes" (p 5-50).
7. A new register bit “UnderWait” is included, that keeps
the Transmitter from sending the back end of a frame
as a new frame, if a Tx DMA channel or software loads
new Tx data after a Tx Underrun has occurred (p 5-50).
8. The /RxREQ logic was changed to eliminate the so-
called “scribbling problem”, wherein /RxREQ was
constantly asserted if a frame ended while the RxFIFO
was in Rx Overrun state (p 5-51).
9. If the new register bit “UnderWait” is set and 32-bit
TSBs are used, the start of frame transmission is
delayed until the TxFIFO is filled or a complete Tx
frame has been loaded, to minimize Tx Underrun
conditions near the start of a frame (p 5-50).
10. Flags can be used as a Preamble, for remote equip-
ment that needs more than one or two of them, or for
slowing down the frame rate slightly for congestion
management (p. 5-53).
11. The /RxREQ logic was changed to improve the reliabil-
ity of forcing out multiple received frames when 32-bit
Receive Status Blocks are used (pp. 6-6, 6-7).
12. A means of identifying the revision level of the device
is provided (p. 8-3).
Zilog’s products are not authorized for use as critical compo-
nents in life support devices or systems unless a specific written
agreement pertaining to such intended use is executed between
the customer and Zilog prior to use. Life support devices or
systems are those which are intended for surgical implantation
into the body, or which sustains life whose failure to perform,
when properly used in accordance with instructions for use
provided in the labeling, can be reasonably expected to result in
significant injury to the user.
Zilog, Inc. 210 East Hacienda Ave.
Campbell, CA 95008-6600
Telephone (408) 370-8000
Telex 910-338-7621
FAX 408 370-8056
Internet: http://www.zilog.com
© 1997 by Zilog, Inc. All rights reserved. No part of this document
may be copied or reproduced in any form or by any means
without the prior written consent of Zilog, Inc. The information in
this document is subject to change without notice. Devices sold
by Zilog, Inc. are covered by warranty and patent indemnification
provisions appearing in Zilog, Inc. Terms and Conditions of Sale
only. Zilog, Inc. makes no warranty, express, statutory, implied or
by description, regarding the information set forth herein or
regarding the freedom of the described devices from intellectual
property infringement. Zilog, Inc. makes no warranty of mer-
chantability or fitness for any purpose. Zilog, Inc. shall not be
responsible for any errors that may appear in this document.
Zilog, Inc. makes no commitment to update or keep current the
information contained in this document.
UM009402-0201