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List:       classiccmp
Subject:    Re: Tatung Einstein disks
From:       ard () p850ug1 ! demon ! co ! uk (Tony Duell)
Date:       2001-03-07 20:21:54
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> 
> >> .... My Einstein came with the 80 column add-on ....
> 
> > I've never seen one, but I've always suspected it was a 6845 + 2K RAM +
> > character generator + TTL glue logic in the obvious configuration. How
> > close am I?
> 
> Not close, exact. The 'MODEL TK02 80 COLUMN MONOCHROME CARD' has:
> UM 6845 8440 , TMM2016BP-10 , TMS2764JL-45 , a 10Mhz oscillator (may

Right... My guess was based on some very shaky evidence (like what 
appears to be a 6845 intialisation table in the ROM). It's nice to know I 
got it right :-)

> be 16 or 18 - can't quite read it and havn't put a 'scope on it yet)
> and fifteen 74LSxxx chips.
> 
> > How much hardware-related info do you have? I can find (easily) things
> > like connector pinouts, etc.
> 
> Absolutely none but I'm not looking further than getting an OS at the moment
> - if it then doesn't work however, I'll remember your kind offer.
> 
> John Honniball asked about the disks in the Einstein - having now taken them
> out of the steel box sleeve which every 3.0" drive seems to come in I can
> report that they are different to the Amstrad PCW8256/8512 drives -
> whereas the Amstrad are the 'infamous slack belt' drives, the drives in my 
> Einstein are Teac direct drive (hurray!).

Incidentally, the 34 pin connector on the back of the drives is a 
standard drive interface connector (like you'd find on a 5.25" drive). In 
fact there's no reason why you can't use 5.25" (normal double density, 
not '1.2Mbyte') or 3.5" drives with the Einstein.

The Internal (M005) and external (M004) drive connectors are electrically 
identical. The Einstein supports 4 drives total. Conventionally, there 
are 2 internal drives configured as Drive 0 and Drive 1 (the Einstein 
disk cable doesn't have the PC-twist -- you have to set the links on the 
drives appropriately) and the exteranl drives are set as Drive 2 and 
Drive 3. This is not enforced, though -- Drive 1 can be external if you like.

Here are some pinouts of various connectors on the machine (if anyone is 
maintaining a site of pinouts, feel free to add these!).

M003 : Tatung Pipe (basically, the system bus) 

  +5V x 1 2 x D7
  +5V x     x D6
  Gnd x     x D5
  Gnd x     x D4
  Gnd x     x D3
  Gnd x     x D2
  Gnd x     x D1
  Gnd x     x D0
  Gnd x     x A15
  A14 x     x A13
  A12 x     x A11
  A10 x     x A9
   A8 x     x A7
   A6 x     x A5
   A4 x     x A3
   A2 x     x A1
   A0 x     x Rst/
  Gnd x     x Rfsh/
  Gnd x     x M1/
  Gnd x     x Busack/
  Gnd x     x Wr/
  Gnd x     x Rd/
  Gnd x     x Iorq/
  Gnd x     x Mreq/
  Gnd x     x Halt/
  Gnd x     x NMI/
  Gnd x     x INT/
  Gnd x     x Wait/
  Gnd x     x Busrq/
  Gnd x     x Clock

M004 (External disks), M005 (Internal disks)
All odd pins : Ground
6 DS3
8 Index
10 DS0
12 DS1
14 DS2
16 Motor On
18 Step Direction
20 Step Pulse
22 Write Data
24 Write Gate
26 Track 0
28 Write Protect
30 Read Data
32 Side Select

M013 : RS232. This is a 5 pin 'domino' DIN plug, and has been wired 
sensibly (unlike the BBC micro) so that turning the plug over gives a 
null-modem swap. Neat!

Top left : RxD Input
Top Right : RTS output
Bottom left : CTS input
Bottom Right : TxD output
Centre : Ground.

There are 2 marked solder pads on the main PCB for DSR and DTR. They're 
at RS232 levels. The serial port is driven by an 8251, with 2 channels of 
a Z80-CTC giving the baud rate clocks.

M001 : Centronics printer 
Strobe x 1 2 x Gnd
    D0 x     x Gnd
    D1 x     x Gnd
    D2 x     x Gnd
    D3 x     x Gnd
    D4 x     x Gnd
    D5 x     x Gnd
    D6 x     x Gnd
    D7 x     x Gnd
   Ack x     x Gnd
  Busy x     x Gnd
   OOP x     x Gnd
       x     x
       x     x Fault
       x     x
   Gnd x     x
   Gnd x     x

This is driven by port A of a Z80 PIO. The strobe comes from ARDY, via a 
'123 monotstable. Ack goes to ASTB. Busy, OOP, Fault are read in via a 
'244 buffer (along with some other signals).

M102 User port :

  +5V x 1 2 x D0
  Gnd x     x D1
 BRDY x     x D2
  Gnd x     x D3
  Gnd x     x D4
 BSTB x     x D5
  Gnd x     x D6
  +5V x     x D7

This is an unbuffered port from port B of the Z80 PIO.

M014, M015 Analogue ports (7 pin DIN).

6 Gnd
1 CH1 (CH3 on second port)
4 SW0 (SW1 on second port) : Switch inputs
2 Analogue ground
5 Vref
3 CH2 (CH4 on second port)
7 +5V

Analogue inputs are read via a (voltage-sensing) ADC0844 ADC chip. Switch 
inputs are read via the same input port as the printer status signals 
above ('244).

M016 : Monitor - 6 pin DIN
1 : R-Y or R
2 : Y or G
3 : B-=Y or B 
4 : Ground or Composite sync
5 : Ground

The functions of the first 4 pins depends on the settings of the jumpers 
M100/M101 on the PCB. If the jumpers are set 'across' (M100 to M101, odd 
pins linked), you get the first set of signals (for driving a special 
Tatung colour-difference input monitor). If the jumpers short adjacent 
pins of M100 (and M101 is left blank) you get analogue RGB for a normal 
monitor.

Hope that helps

-tony

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