[MAME]

Sega System E Hardware Overview
Sega, 1985-1988

This PCB is essentially a Sega Master System home console unit, but using
two '315-5124' VDPs and extra RAM.
The CPU is located on a plug-in board that also holds all of the EPROMs.

The games that run on this hardware include....
Hang-On Jr.             1985
Transformer/Astro Flash 1986
Riddle of Pythagoras    1986
Opa Opa                 1987
Fantasy Zone 2          1988
Tetris                  1988

PCB Layout
----------
834-5803 (C)Sega 1985
|-----------------------------------------------------|
|         D4168      D4168      D4168       D4168     |
|                                                     |
|         D4168      D4168      D4168       D4168     |
|                                                     |
|                                                     |
|    SW1                                              |
|CN1                                                  |
|    SW2                                              |
|                                                     |
|   LED            |---|             |---|            |
|                  | 3 |             | 3 |            |
|                  | 1 |             | 1 |            |
|                  | 5 |             | 5 |            |
|                  | | |             | | |         CN3|
|                  | 5 |             | 5 |     8255   |
|CN4               | 1 |             | 1 |            |
|                  | 2 |             | 2 |            |
|                  | 4 |             | 4 |            |
|                  |---|             |---|            |
|               |--------ROM-BOARD-(above)---------|  |
|               |                                  |  |
|               |CN2                   10.7386MHz  |  |
|               |         D4168                    |  |
|  VOL          |         D4168                    |  |
| LA4460        |----------------------------------|  |
|-----------------------------------------------------|
Notes:
      315-5124 VDP clock - 10.7386MHz
      SN76496 clock      - 3.579533MHz [10.7386/3]
      D4168              - 8k x8 SRAM
      VSync              - 60Hz
      HSync              - 15.58kHz
      CN1                - Connector used for standard controls
      CN2                - connector for CPU/ROM PCB
      CN3                - Connector used for special controls (via a small plug-in interface PCB)
      CN4                - Connector for power

ROM Daughterboard
-----------------
834-6592-01
|--------------------------------------------|
|                                            |
|    |---|                                   |
|C   |   |                           IC6     |
|N   |Z80|                                   |
|2   |   |                                   |
|    |   |   IC2   IC3   IC4   IC5        IC7|
|    |---|                                   |
|     IC1             PAD1 PAD2     PAD3 PAD4|
|--------------------------------------------|
Notes:
       IC1: Z80 clock - 5.3693MHz [10.7386/2]
            On some games this is replaced with a NEC MC-8123 Encrypted CPU Module.
            The clock speed is the same. The MC-8123 contains a Z80 core, plus a RAM chip
            and battery. When the battery dies, the program can no longer be decrypted
            and the PCB does not boot up at all. The battery can not be changed because the
            MC-8123 is sealed, so there is no way to access it.

 IC2 - IC5: 27C256 EPROM (DIP28)

       IC6: 74LS139

       IC7: 27C256 EPROM (DIP28)

    PAD1-4: These are jumper pads used to configure the ROM board for use with the
            Z80 or with the MC8123 CPU.
            PAD1 - Ties Z80 pin 24 (WAIT) to pin1 of the EPROMs at IC2, 3, 4 & 5
            PAD2 - Ties CN2 pin B21 to pin1 of the EPROMs at IC2, 3, 4 & 5
            PAD3 - Ties CN2 pin B21 to pin 2 of the 74LS139 @ IC6
            PAD4 - Ties Z80 pin 24 (WAIT) to pin 2 of the 74LS139 @ IC6

            The pads are configured like this..... (U=Upper, L=Lower)

                                                 |----|      |----|
                                                 |IC6 |      |IC7 |
                                                 |  12|------|22  |
                                                 |    |      |    |
                       IC2   IC3    IC4   IC5    |   1|------|27  |
                       PIN1  PIN1   PIN1  PIN1   |   2|--|   |    |
                        O-----O--+---O------O    |----|  |   |----|
                                 |                       |
                                 |         |----|        |
                              O--+----O    |    O    |---O
            CN2    Z80      PAD1U   PAD2U  |  PAD3U  | PAD4U
            B21    PIN24    PAD1L   PAD2L  |  PAD3L  | PAD4L
             O       O--4.7k--O       O----|    O----|   O
             |                |       |                  |
             |                |-------|------------------|
             |                        |
             |------------------------|

            When using a regular Z80B (and thus, unencrypted code):
            PAD1 - Open
            PAD2 - Open
            PAD3 - Shorted
            PAD4 - Open

            When using an encrypted CPU module (MC-8123):
            PAD1 - Open
            PAD2 - Shorted
            PAD3 - Open
            PAD4 - Open
            Additionally, a wire must be tied from CN2 pin B22 to the side
            of PAD3 nearest IC6 (i.e. PAD3U).

ROMs:
-----

Game                     IC2         IC3         IC4         IC5         IC7
---------------------------------------------------------------------------------
Hang-On Jr.              EPR-?       EPR-?       EPR-?       EPR-?       EPR-?     Hello, Sega Part Numbers....!?
Transformer              EPR-7350    EPR-?       EPR-7348    EPR-7347    EPR-?     Ditto
           /Astro Flash  EPR-7350    EPR-7349    EPR-7348    EPR-7347    EPR-7723
Riddle of Pythagoras     EPR-10422   EPR-10423   EPR-10424   EPR-10425   EPR-10426
Opa Opa                  EPR-11220   EPR-11221   EPR-11222   EPR-11223   EPR-11224
Fantasy Zone 2           EPR-11412   EPR-11413   EPR-11414   EPR-11415   EPR-11416
Tetris                   -           -           EPR-12211   EPR-12212   EPR-12213

A System E PCB can run all of the games simply by swapping the EPROMs plus CPU.
Well, in theory anyway. To run the not-encrypted games, just swap EPROMs and they will work.

To run the encrypted games, use a double sized EPROM in IC7 (i.e. a 27C512)
and program the decrypted opcodes to the lower half and the decrypted data to the upper half,
then connect the highest address pin of the EPROM (A15 pin 1) to the M1 pin on the Z80.
This method has been tested and does not actually work. An update on this may follow....


System E PCB Pinout
-------------------

CN1
---

+12V             1A  1B  Coin switch 1
Coin switch 2    2A  2B  Test switch
Service switch   3A  3B
                 4A  4B  1P start
2P start         5A  5B  1P up
1P down          6A  6B  1P left
1P right         7A  7B  1P button 1
1P button 2      8A  8B
                 9A  9B  2P up
2P down          10A 10B 2P left
2P RIGHT         11A 11B 2P button 1
2P button 2      12A 12B
                 13A 13B Video RED
                 14A 14B Video GREEN
                 15A 15B Video BLUE
                 16A 16B Video SYNC
                 17A 17B
                 18A 18B
Speaker [+]      19A 19B
Speaker [-]      20A 20B
Coin counter GND 21A 21B
GND              22A 22B Coin counter 1
                 23A 23B Coin counter 2
                 24A 24B
                 25A 25B
CN4
---

+5V  1A 1B +5V
+5V  2A 2B +5V
     3A 3B
GND  4A 4B GND
GND  5A 5B GND
+12V 6A 6B +12V
+12V 7A 7B +12V
GND  8A 8B GND

-