Question: IBM 6580 Displaywriter S/36 -15pin Keyboard

[Swamp_Donkey]

I don't know many people that would risk damaging a $1000+ keyboard to find out if the rom is any different, though.

I mean, I am happy to send you the controller card if you want to desolder the chip do a dump of the ROM. It attaches via edge connector, so I can just slide it back on the keyboard when you are finished.

It is 192kB Present as MSDos found out after Boot.
Can't find any document about these mem block, or how many each block should be.

Do I need a system setup or check to store that way the amount of mem installed?
As I have a second mem-card I populated those empty sockets as well and took out that middle strap, as
I found on picture on the internet, with full populated the straps are all out.
But no difference at that mem count.

This has to do with how MSDOS bootstraps itself. It does its own check of the system RAM to determine its size value. Textpack, CP/M and the CED diagnostics use the results of the BAT tests performed at power on. When a BAT test fails during power on, it tries to put the system into a "limp mode" of sorts and only reports the first 128k of ram. So Textpack, CED and CP/M will show 128k ram when a BAT test fails. MSDOS overrides this because it does its own test. This is why you're seeing the discrepancy. The memory chips are either 64k or 32k. The board pictured has two 64k (left side, thicker chips) and two 32k (right side, socketed) for 192k total.

A model F keyboard is on its way with 15pin connector (think of a Terminal IBM), and a Keyboard CPU Displaywriter board taken out of an bigfoot, as we know why.
That contains the org 8049 cpu.
So hope to construct that way a working keyboard.

Even with another keyboard that contains a 8048/8049 CPU I'm dubious as to whether it will work without a ROM flash. As I stated before the keyboard has diagnostics specific to the DW programmed in it, and needs to report a keyboard ID number as this number is used in Textpack.
When the Displaywriter boots it first initializes the keyboard diagnostic. The keyboard diagnostic then sends three bytes of data back, two to confirm that the test passed and a third to report the keyboard ID number. The data is then verified by the DW.
The process that the Displaywriter BIOS is expecting is:
-Power on
-BAT diagnostic signal sent to keyboard
-BAT test performed by keyboard
-BAT successful completion codes
-Displaywriter system verifies data sent
-Keyboard sends Keyboard ID number (controlled with blue jumpers)
A fully functional keyboard would either need to comply with or circumvent this process.

 

[MauriceH]

Thanks for explaining the difference in MEM check.
Indeed at power-up I have off-course that keyboard fail, so its in limp mode, OK.

I get an original Displaywriter keyboard pcb. That is Its been send out as be one.
So that 8049 should have the right ROM flash.
If not I have to make my own completely.

As looking at the flowchart I indeed suspect some keyboard control check communication.

Hope I get it to work,

 

[Rodi]

The keyboard that is on its way is a bigfoot from an IBM 5291 terminal, and a second bigfoot keyboard from an IBM 3178 terminal. With a little luck together with the displaywriter controller we can do a mix and match and get a sort of working solution. Some special keys may need remapping I suppose. We'll see. Else the boards end up in the display case