5 Apr
2005
5 Apr
'05
7:45 p.m.
Well, let's try to give an answer.
The SWitch Register is what is says: *switch* register.
So you can read the switches from it, but writing to it is no use.
Don't shoot me if I am mistaken! From memory, the address is 777570.
- Henk, PA8PDP.
-----Original Message-----
From: cctalk-bounces at classiccmp.org
To: Classic computer list
Sent: 5-4-2005 21:33
Subject: PDP 11/45 Display register.
Hi,
A quick question raised by my ongoing work....
Is it possible to write directly to the "display register" - the one
accessed by one position of the data switch. I think it should be at
memory
location 777570, but I can't get data into it, either using deposit from
the
console, or moving data under program control.
Have I got a fault, or am I doing something wrong?
Thanks
Jim.
Please see our website the " Vintage Communication Pages" at
WWW.G1JBG.CO.UK
5 Apr
5 Apr
8:11 p.m.
Almost.
The SR and the DR are at the same memory location. Reading gives the
switch settings (the low 16 bits worth), writing sets the display
register, assuming the Data Display Switch is set correctly. You
cannot read back what you have written, you will always get the
switch settings.
Can't say if you have a fault or are doing something incorrectly yet.
Not certain you can set the display register from the console.
Someone with a live /45 might check that.
John
At 9:45 PM +0200 4/5/05, Gooijen H wrote:
Well, let's try to give an answer.
The SWitch Register is what is says: *switch* register.
So you can read the switches from it, but writing to it is no use.
Don't shoot me if I am mistaken! From memory, the address is 777570.
- Henk, PA8PDP.
-----Original Message-----
From: cctalk-bounces at classiccmp.org
To: Classic computer list
Sent: 5-4-2005 21:33
Subject: PDP 11/45 Display register.
Hi,
A quick question raised by my ongoing work....
Is it possible to write directly to the "display register" - the one
accessed by one position of the data switch. I think it should be at
memory
location 777570, but I can't get data into it, either using deposit from
the
console, or moving data under program control.
Have I got a fault, or am I doing something wrong?
Thanks
Jim.
Please see our website the " Vintage Communication Pages" at
WWW.G1JBG.CO.UK
9:38 p.m.
>>>> "Gooijen" == Gooijen H
<Gooijen> writes:
Gooijen> Well, let's try to give an answer. The SWitch Register is
Gooijen> what is says: *switch* register. So you can read the
Gooijen> switches from it, but writing to it is no use. Don't shoot
Gooijen> me if I am mistaken! From memory, the address is 777570.
The switches are read-only at 777570; the display register is
write-only at the same address.
paul
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dundas＠caltech.edu -
GOOI＠oce.nl -
pkoning＠equallogic.com