11/45 progress

Gooijen H GOOI at oce.nl
Fri Mar 4 15:36:17 CST 2005


> Jay wrote about a DL11:
> If I exam 776500, I get a 200,
> but anytime I store a value and read it back, there's all 
> zero's in the data register.

I will dig up my notes getting characters in and out a M7800
in my 11/35 resurrection using the front panel several years
ago.
This is also an advice: make notes of *everything* you do on
a system, no matter how trivial at this time. Changing a wire,
trying some toggle in tests on the console, behaviour, measured
voltages on pins, etc.
If problems occur later you can go back and do all tests from
your notes. That's why I can write my tests with the M7800 when
I get home (in a few hours from now).

- Henk, PA8PDP.


These are a few of my notes.

Console board: 2 versions. M7800 and M7800-YA
M7800:
Xtal = 4608 kHz, has 1448/1449
jumpers: A3,A4,A5,A7,A9
open: A6,A8,A10
base address = 776500
baudrate = 1200 Bd.

M7800-YA:
Xtal = 1152 kHz, no 1448/1449 (20mA current loop only)
jumpers: A0,A7
open: A4,A5,A6,A8,A9,A10
base address = 777560 (console)
baudrate = 1200 Bd.

console registers:
RCSR 777560
RBUF 777562
XCSR 777564
XBUF 777566

Hit the key "1" of the keyboard
If RCSR contains 0200 it means that a character is received.
To check this:
1) set the SR to 777560.
2) press LOAD ADDRESS  --> the ADDRESS LEDs show 777560
3) press EXAM
4) the DATA LEDs show 000200
RBUF should contain 061 (ASCII "1").
To check this:
1) set the SR to 777562.
2) press LOAD ADDRESS  --> the ADDRESS LEDs show 777562
3) press EXAM
4) the DATA LEDs show 000061
Load 065 in XBUF --> the screen should show a "5".
Operation:
1) set the SR to 777566.
2) press LOAD ADDRESS  --> the ADDRESS LEDs show 777566
3) set the SR to 000065
4) press DEP

Simple test of the CPU.
1) set the SR to 777570 (the switch register address).
2) press LOAD ADDRESS  --> the ADDRESS LEDs show 777570
3) set the SR to 000777  (this is BRA .  branch to myself)
4) press START
The ADDRESS LEDs show 777572.
CONSOLE LED is off, RUN, BUS, PROC LEDs are on.
When you press HALT, CONSOLE LED goes on.

- Henk, PA8PDP.




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