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#108359 - 01/06/17 04:42 PM Re: IBM Displaywriter (1980) WIP [Re: shattered]
Al Kossow Offline
Senior Member

Registered: 01/06/11
Posts: 144
Originally Posted By shattered
upd765 chip is actually available on system bus (ports 8158, 815A) and with a few hacks I forced firmware to talk to it; unsuccessfully so far -- scan ID phase fails. Maybe the FM bitrate is wrong...


the FM and MFM images use normal FDC bitrates, otherwise I couldn't have imaged them.

there is a mix of 1S FM and 2S MFM IMD files for the diagnostics

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#108360 - 01/06/17 04:50 PM Re: IBM Displaywriter (1980) WIP [Re: shattered]
shattered Offline
Senior Member

Registered: 05/30/12
Posts: 366
indeed, with rate hardcoded to 500000 and a few more hacks it manages to IPL. f.e. this is Textpack A image from bitsavers:

Code:
[:upd765] command read data cmd=06 sel=0 chrn=(0, 0, 7, 128) eot=1a gpl=07 dtl=80 rate=500000
[:upd765] command read data cmd=06 sel=0 chrn=(0, 0, 1, 128) eot=1a gpl=07 dtl=80 rate=500000
[:upd765] command read data cmd=06 sel=0 chrn=(1, 0, 1, 256) eot=0f gpl=0e dtl=ff rate=500000
[:upd765] command read data cmd=06 sel=0 chrn=(1, 0, 4, 256) eot=0f gpl=0e dtl=ff rate=500000
[:upd765] command read data cmd=06 sel=0 chrn=(1, 0, 5, 256) eot=0f gpl=0e dtl=ff rate=500000
[:upd765] command read data cmd=06 sel=0 chrn=(1, 0, 15, 256) eot=0f gpl=0e dtl=ff rate=500000
[:upd765] command read data cmd=06 sel=0 chrn=(2, 0, 1, 256) eot=0f gpl=0e dtl=ff rate=500000


Doesn't run very far though


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#108368 - 01/07/17 05:48 PM Re: IBM Displaywriter (1980) WIP [Re: shattered]
shattered Offline
Senior Member

Registered: 05/30/12
Posts: 366
With ROMs from bitsavers (apparently an older rev), CED and PDD disks boot but still complain about floppy. But hey, I got a Service Request number :-)



+


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#108369 - 01/08/17 11:26 AM Re: IBM Displaywriter (1980) WIP [Re: shattered]
shattered Offline
Senior Member

Registered: 05/30/12
Posts: 366
Getting there... bit 6 in floppy status port (8150) apparently reflects 'idle' status of MCU and upd765 both. Diagnostics disks are now usable and CCP/M boots. Textpack does not yet.


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#108394 - 01/10/17 09:33 PM Re: IBM Displaywriter (1980) WIP [Re: shattered]
shattered Offline
Senior Member

Registered: 05/30/12
Posts: 366
Textpack 1 probably crashes because 128KB is not enough memory for it, but simply mapping more memory does not make it work and diags don't detect extra memory as well... So instead, here's how 66-line display is supposed to look. Only works with "new" firmware:


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