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The Expansion Interface
The expansion interface is quite different from the TRS-80. On the Video Genie it is gold plated as was the cable that came with the expansion box. It is also similar to the later TRS-80 EI, generating RAS and CAS in the EI. For me it has worked very well. I have never had any trouble with it. It is not like the original where it seems to be necessary to wriggle the plugs once in a while (to get it to boot). Comparing it with info at Pete Cervasio's TRS-80 home page ((external) (wayback) main page) (external) (wayback) directly to the model 1 pin listing it seems that the Video Genie has more of the CPU signals "straight" from the source. Especially the ability to isolate the CPU and take control of the address bus and control signals is a good feature, an improvement on the original.
Pin Connection for Expansion Interface
PIN
Signal name
 Comment
dir
 1 2 CPU relation etc.
1
GND
          
2
GND
          
3
A7
  
O
   * A7 buffered by LS367
4
A6
  
O
   * A6 buffered by LS367
5
A5
  
O
   * A5 buffered by LS367
6
A4
  
O
   * A4 buffered by LS367
7
A1
  
O
   * A1 buffered by LS367
8
A3
  
O
   * A3 buffered by LS367
9
A2
  
O
   * A2 buffered by LS367
10
A0
  
O
   * A0 buffered by LS367
11
D5
  
I/O
   * D5 buffered by LS367
12
D2
  
I/O
   * D2 buffered by LS367
13
nc
 no connection        
14
D1
  
I/O
   * D1 buffered by LS367
15
D0
  
I/O
   * D0 buffered by LS367
16
D3
  
I/O
   * D3 buffered by LS367
17
D7
  
I/O
   * D7 buffered by LS367
18
D6
  
I/O
   * D6 buffered by LS367
19
VCC
         5V (used to power the EG3016 printer interface etc.)
20
D4
  
I/O
   * D4 buffered by LS367
21
A15
  
O
   * A15 buffered by LS367
22
A8
  
O
   * A8 buffered by LS367
23
A14
  
O
   * A14 buffered by LS367
24
A9
  
O
   * A9 buffered by LS367
25
nc
 no connection        
26
A10
  
O
   * A10 buffered by LS367
27
A13
  
O
   * A13 buffered by LS367
28
A11
  
O
   * A11 buffered by LS367
29
A12
  
O
   * A12 buffered by LS367
30
PHI
 1.79 MHz clock
O
     F directly
31
PINT
 Interrupt
I
     INT w/4K7 pullup
32
nc
 no connection        
33
nc
 no connection        
34
PHLDA
 Hold Acknowledge
O
     BUSAK buffered with LS367 permanetly enabled
35
PHANTOM
 Phantom
I
     Disables memory read (S100 entity)
36
HALT
 Halt Acknowledge
O
     HALT buffered with LS367 permanetly enabled
37
PWAIT
 Wait
I
     WAIT directly
38
IORQ
 Input/Output Request
O
 *   IORQ buffered with LS367
39
PHOLD
 Hold
I
     BUSRQ w/4K7 pullup
40
WR
 Write
O
 *   WR buffered with LS367
41
RD
 Read
O
 *   RD buffered with LS367
42
CCDBS/STADBS
 Control and status bus disable
I
!
   Disables signals; RFSH, IORQ, WR, RD,MREQ and M1
43
MREQ
 Memory Request
O
 *   MREQ buffered with LS367
44
DODBS/ADDBS
 Data and adress bus disable
I
  
!
 Disables D? and A?? signals
45
M1
 First state of instruction cycle
O
 *   M1 buffered with LS367
46
RESET
 CPU Reset ()
I/O
     RESET directly wired-or with powerup reset pulse
47
RFSH
 Dynamic memory refresh
O
 *   RFSH buffered with LS367
48
NMI
 Non-Maskable Interrupt
I/O
     NMI direcly wired-or with "Reset" button, 4K7 pullup
49
GND
          
50
GND
          
1 Disabled by CCDBS/STADBS pulled low, can then be driven through the expansion port.
2 Disabled by DODBS/ADDBS pulled low, can then be driven through the expansion port.

As seen from the back of the Video Genie:
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-#--#--#--#--#--#--#--#--#--#--#--#--#--#--#--#--#--#--#--#--#--#--#--#--#-
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