4 Apr
2006
4 Apr
'06
1:36 a.m.
Hi!
I got a M7270 CPU module here from my PDP-11/03. It has the tracks to
the QBus contacs BC1-BF1 (BDAL18, BDAL19, BDAL20, BDAL21) cut.
I of course wondered why one would do that. In [2] I found the following
hint:
---
II. Restricted Compatibility Options
Options in this category do not meet one or both of the requirements for
use in a 22-bit system. These options are incompatible with some or all
22-bit systems.
...
KD11-HA M7270 LSI-11/2 CPU
(16-bit addressing only, and use of BC1,BD1,
BE1,BF1 for purposes other than BDAL18-21)
---
So I guess someone tried to make the CPU compatible with 18/22-bit modules?
What did the M7270 use these pins for? I didn't find any manuals or
schematics for the this CPU yet, only for the LSI-11. Could someone
point me into the right direction?
Thanks
Sebastian
[1] http://www.bitsavers.org/pdf/dec/pdp11/1103/EK-LSI11-TM-002.pdf
[2]
http://www.ibiblio.org/pub/academic/computer-science/history/pdp-11/hardwar…
4 Apr
4 Apr
2:47 a.m.
On Tue, 4 Apr 2006, [ISO-8859-15] Sebastian Br?ckner wrote:
KD11-HA M7270 LSI-11/2 CPU
(16-bit addressing only, and use of BC1,BD1,
BE1,BF1 for purposes other than BDAL18-21)
What did the M7270 use these pins for? I didn't find any manuals or
schematics for the this CPU yet, only for the LSI-11. Could someone point me
into the right direction?
According to the "microcomputer processor handbook" (edition 1979-80) the
backplane signal names for BC1 to BH1 are called SSPARE4 to SSPARE8
(special spare) and are *not* bussed. The KD11-HA signal names on these
pins are:
BC1 SCLK3H
BD1 SWMIB18H
BE1 SWMIB19H
BF1 SWMIB20H
BH1 SWMIB21H
Christian
4:09 a.m.
Christian Corti schrieb:
According to the "microcomputer processor
handbook" (edition 1979-80)
the backplane signal names for BC1 to BH1 are called SSPARE4 to SSPARE8
(special spare) and are *not* bussed.
Yes but that apparently is only true for the very first machines using
QBUS i.e. with the LSI-11 CPU. The LSI-11 manual contains exactly the
same information.
The KD11-HA signal names on these
pins are:
BC1 SCLK3H
BD1 SWMIB18H
BE1 SWMIB19H
BF1 SWMIB20H
BH1 SWMIB21H
Any idea how I can find out what those signals actually do?
Sebastian
14 Apr
14 Apr
4:09 p.m.
On Tuesday 04 April 2006 05:47, you wrote:
On Tue, 4 Apr 2006, [ISO-8859-15] Sebastian Br?ckner
wrote:
The signals control several flip-flops on the M7270 as follows:
BC1 phase 3 clock, active high - enable for the decoding of the other bits
BH1 high to enable decoding
BD1 BE1 BF1
000 not used
001 clear init FF
010 bus timeout FF clear
011 not used
100 init FF set
101 set FDIN FF
110 power fail FF clear
111 event FF clear
Since the 4 lines have a large number ( 10 ) of unused combinations, and
are driven directly by the microcode, they could have any number
of uses if you're runing writable control store.
Can an M7270 do that?
If you're running the standard MCROMS they don't have much value
outside the CPU.
joe lang
KD11-HA M7270 LSI-11/2 CPU
(16-bit addressing only, and use of BC1,BD1,
BE1,BF1 for purposes other than BDAL18-21)
What did the M7270 use these pins for? I didn't find any manuals or
schematics for the this CPU yet, only for the LSI-11. Could someone point
me into the right direction?
According to the "microcomputer processor handbook" (edition 1979-80) the
backplane signal names for BC1 to BH1 are called SSPARE4 to SSPARE8
(special spare) and are *not* bussed. The KD11-HA signal names on these
pins are:
BC1 SCLK3H
BD1 SWMIB18H
BE1 SWMIB19H
BF1 SWMIB20H
BH1 SWMIB21H
Christian
6828
days inactive
6838
days old
3 comments
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