[Simh] DEC VT emulators on MAME

[Armistead, Jason]

Tim

Malcolm had previously indicated that E80 was a Xicor X2804AP-45 chip.  That would make it a 512 byte (4096 bit arranged as 512 * 8)  EEPROM, rather than an NVRAM, with an access time of 450ns.

Link to datasheet http://pdf1.alldatasheet.com/datasheet-pdf/view/103364/XICOR/X2804A.html

This chip should be easily readable by almost any PROM/EPROM/EEPROM programmer, but if it's only got settings as you suspect, then hopefully the firmware would be able to identify a blank device and just set up defaults.

Jason

-----Original Message-----
From: Simh [mailto:simh-bounces at trailing-edge.com] On Behalf Of Tim Stark
Sent: Sunday, 16 April 2017 1:24 AM
To: malcolm at avitech.com.au; 'Cory Smelosky'
Cc: simh at trailing-edge.com
Subject: Re: [Simh] DEC VT emulators on MAME

Malcolm,

Ok, thanks for let us know.  I now found video docs for VT340 (dragon system - vipers and adders).  Each chip hold one bitmap plane individually. VCB02 graphics card uses the same chips. 

I misread schematics.    I believe that E80 is NVRAM chip for just settings - 512 x 8,  not 512K x 8.  Firmware is in ROM cartridge.  

E49 dump should be labelled as 236E6.bin for CG rom. 

Does anyone have a copy of CRT 9007 video controller docs for VT220 terminal?

Thanks,
Tim

-----Original Message-----
From: malcolm at avitech.com.au [mailto:malcolm at avitech.com.au] 
Sent: Saturday, April 15, 2017 9:43 PM
To: 'Tim Stark' <fsword7 at verizon.net>; 'Cory Smelosky' <b4 at gewt.net>
Cc: simh at trailing-edge.com
Subject: RE: [Simh] DEC VT emulators on MAME

I've now pulled apart a spare non-working VT340, for the ROM dumps. This terminal has a faulty power supply and very significant screen burn, so I wasn't planning on repairing it anyway.

On my board, E80 is a XICOR X2804AP-45 which is soldered in place. So I haven't removed it or dumped its contents.

E49 is a 27256 EPROM.  I have dumped the content of that ROM and it is now available here -> https://urldefense.proofpoint.com/v2/url?u=http-3A__avitech.com.au_-3Fp-3D1818&d=DwIGaQ&c=ilBQI1lupc9Y65XwNblLtw&r=CeQuuq99aEH_1RE1yGnGXY4AbMg6_1cjkYeJjaT-sd4&m=YpwywTuCsVKkSvuZSul6C6BTase_SV-J2yCTQkZVeBQ&s=WAvNJXtV69LsjK_LBZBMcmtmo-gwnd1OPsJy0_seTI0&e=  

That page also has pictures of the VT340 internals.

Tim - I will write to you separately to arrange sending the VT340 logic board to you.

Malcolm.

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