GAL 22V10 - DivIDE 512kB LOW-PRICE UPGRADE
==========================================


GAL pinout:

Pin   Label               Type
---   -----               ----
1     CLK                 clock pin
2     mapcond             pos,com input
3     /poweron            neg,com input
4     /eprom              neg,com input
5     d1                  pos,com input
6     d2                  pos,com input
7     d3                  pos,com input
8     d4                  pos,com input
9     d5                  pos,com input
10    d6                  pos,com input
11    d7                  pos,com input
12    GND                 ground pin
13    a13                 pos,com input
14    switch              pos,trst,reg feedback
15    /en_nmi             neg,trst,com output
16    allram              pos,trst,reg feedback
17    mode2               pos,trst,reg feedback
18    mode1               pos,trst,reg feedback
19    /adrres             neg,trst,com output
20    out2                pos,trst,reg output
21    out3                pos,trst,reg output
22    out4                pos,trst,reg output
23    out5                pos,trst,reg output




                             GAL 22V10 (5DIVI2)

                              ._____    _____.
                              |     \__/     |
      (m_gal pin 18 )     CLK |  1        24 | VCC     (connect to +5V - to r_gal pin 24)
      (a_gal pin 19 ) mapcond |  2        23 | out5    (connect to SRAM A18 )
      (from R6 )     /poweron |  3        22 | out4    (connect to SRAM A17 )
      (m_gal pin 11 )   eprom |  4        21 | out3    (via resistor 470 Ohm connect to SRAM A16 )
      (IC5 pin 3 )         d1 |  5        20 | out2    (via resistor 470 Ohm connect to SRAM A15 )
      (IC5 pin 4 )         d2 |  6        19 | /adrres (2x Diode 1N4148 --|<|-- /first diode connect to SRAM A15,second with SRAM A16 )
      (IC5 pin 5 )         d3 |  7        18 | mode1
      (IC5 pin 6 )         d4 |  8        17 | mode2
      (IC5 pin 7 )         d5 |  9        16 | allram
      (IC5 pin 8 )         d6 | 10        15 | /en_nmi (connect new NMI button --/ -- + R 1M connect with C 470pF(parallel with R 1M) and output connect to /NMI on ZX bus). Remove orig.DIVIDE NMI button and R4 !
      (IC5 pin 9 )         d7 | 11        14 | switch  (replace R5 with resistor 470 Ohm. R5 disconnect from +5V and connect to this pin)
      (IC5 pin 10 )       GND | 12        13 | a13     (m_gal pin 10 )
                              |______________|



New NMI button can work also in allram mode.



SOCKET FOR SRAM 512kB:
======================

Remove pins 2, 30 and 31 from ram socket (DIL 32)
Connect pin 32 of ram socket to +5V.



SRAM 512kB PINOUT:
==================

628512  512kx8 SRAM. 
    +-----+--+-----+
A18 |1    +--+   32| VCC
A16 |2           31| A15
A14 |3           30| A17
A12 |4           29| /WE
 A7 |5           28| A13
 A6 |6           27| A8
 A5 |7           26| A9
 A4 |8   628512  25| A11
 A3 |9           24| /OE
 A2 |10          23| A10
 A1 |11          22| /CE
 A0 |12          21| D7
 D0 |13          20| D6
 D1 |14          19| D5
 D2 |15          18| D4
GND |16          17| D3
    +--------------+




MEMORY PAGING PORT:
===================

DivIDE upgrade support 4 paging modes.
Support software controll of jumper "EPROM".

CHANGE PAGING MODE:
OUT 227,11xJABxx
- D7 and D6 must be log.1
- bits signed as "x" is unused
- A and B select type of paging mode 0-3
- J=0 connect jumper EPROM / J=1 disconnect jumper EPROM

PAGING MODE 0:
memory paging vith port 227 - bits function:
D0-D1 = DIVIDE 8kB page 0-3
D2-D5 = DivIDE memory block(32kB RAM) number(0-15)
D6 = mapram
D7 = conmem
Allram in modes 0-3:
D0-D4 = DIVIDE 16kB ram page(0-31)
D5 = unused
D6 = 1-write enable ram / 0-write disable ram
D7 = mapram OFF