source: rtems/c/src/lib/libbsp/powerpc/dmv177/QUIRKS @ 1c5f4e1

4.104.114.84.95
Last change on this file since 1c5f4e1 was 1c5f4e1, checked in by Joel Sherrill <joel.sherrill@…>, on Jul 30, 1998 at 7:26:47 PM

Fixed spacing.

  • Property mode set to 100644
File size: 2.1 KB
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1#
2#  Quirks in the DY-4 DMV177
3#
4#  $Id$
5#
6
7Exar 88681 Clock
8================
9This board uses a different clock for the Exar 88681 DUART than is
10documented in the Exar manual or the original MC68681 manual.  This
11resulted in the need for the the mc68681 libchip driver to support
12BSP specific baud rate tables and the development of a DMV177
13specific baud rate table.
14
15In the end, this all works but you have a very limited range of
16useful baud rates on the 88681 ports compared to what would have
17been supported had DY-4 just followed the Exar or Motorola manual.
18
19
20SCC Addresses
21=============
22The full set of SCC addresses is not documented in the DY-4 manual
23and they are not ordered as one would expect.  Normally the four
24SCC registers are ordered Control A, Data A, Control B, and Data B.
25DY-4 orders them with B first.
26
27This required extra time to debug.
28
29
30SCV64 and the Foundation Firmware
31=================================
32DY-4 technical support did not offer code to determine which interrupt
33sources were pending at the SCV64.  They recommended calling into the
34Foundation Firmware ROM monitor to figure this out.  The Foundation
35Firmware did not recognize enough interrupts on this board to be useful.
36
37In the end, we gave up on their technical support's recommendation
38and directly manipulated the SVC64.  This is what we wanted to do in
39the first place but we got no information from them to aid in this.
40Luckily, the manual does document enough of DY-4's mapping of the specific
41interrupt sources to make this work.
42
43
44Z85C30 SCC Clock Speed
45======================
46
47The Z85C30 SCC can be factory configured for 10 Mhz or 2.4616 Mhz.  Code
48had to be added to dynamically determine which clock was installed.
49
50The board we had used a 10 Mhz clock.  No testing was done with a 2.4616 Mhz
51clock.
52
53
54P2 Octopus Cable
55================
56
57DY-4's P2 breakout is large and a bit unwieldy.  It was difficult to
58fight into the VME cage we used.  The SCSI connector comes off the
59side and is very stiff thus making it difficult to route around
60anything in the back of the cage.  We gave up on trying to use
61it in the first few slots of OAR's cage.
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