Connectors
Notes
- Input mean from device (cart or megacd for example) to Megadrive.
- Output mean from MegaDrive to device
Cartridge Connector
| Front Side | Back Side | ||||||
|---|---|---|---|---|---|---|---|
| Pin Number | Name | I/O | Description | Pin Number | Name | I/O | Description |
| B01 | SL1 | Input | Left audio from cart | A01 | GND | Ground | |
| B02 | /MRES | Unknow | Active low
hard (bootup) reset |
A02 | Vcc1 | Output | Positive supply voltage (+5V) |
| B03 | SR1 | Input | Right audio from cart | A03 | VA8 | Output | |
| B04 | VA09 | Output | A04 | VA11 | Output | ||
| B05 | VA10 | Output | A05 | VA7 | Output | ||
| B06 | VA18 | Output | A06 | VA12 | Output | ||
| B07 | VA19 | Output | A07 | VA6 | Output | ||
| B08 | VA20 | Output | A08 | VA13 | Output | ||
| B09 | VA21 | Output | A09 | VA5 | Output | ||
| B10 | VA22 | Output | A10 | VA14 | Output | ||
| B11 | VA23 | Output | A11 | VA4 | Output | ||
| B12 | /YS | Output | Active low
Mean that VDP is currently drawing the backdrop color |
A12 | VA15 | Output | |
| B13 | /VSYNC | Output | Active low
Vertical Sync |
A13 | VA03 | Output | |
| B14 | /HSYNC | Output | Active low
Horizontal Sync |
A14 | VA16 | Output | |
| B15 | EDCLK | Output | VDP related clock, variable, changes between Mclk/5 ~ Mclk/4 | A15 | VA2 | Output | |
| B16 | /CAS0 | Output | Active low
set for reads on $000000-$DFFFFF acts as /OE signal |
A16 | VA17 | Output | |
| B17 | /CEO | Output | Active low
Chip Enable set for r/w at/to $000000-$3FFFFF when cart is inserted or at/to $400000-$7FFFFF when not |
A17 | VA01 | Output | |
| B18 | /AS | Output | Active low
Address Strobe - addr bus valid |
A18 | GND | Ground | |
| B19 | VCLK | Output | 68k clock | A19 | VD7 | Input/Output | |
| B20 | /DTAK | Input | Data Transfer acKnowledge for 68k | A20 | VD0 | Input/Output | |
| B21 | /CAS2 | Unknown | Unknown | A21 | VD8 | Input/Output | |
| B22 | VD15 | Input/Output | A22 | VD6 | Input/Output | ||
| B23 | VD14 | Input/Output | A23 | VD01 | Input/Output | ||
| B24 | VD13 | Input/Output | A24 | VD09 | Input/Output | ||
| B25 | VD12 | Input/Output | A25 | VD05 | Input/Output | ||
| B26 | /ASEL | Output | Active low
set for r/w at/to $000000-$7FFFFF |
A26 | VD02 | Input/Output | |
| B27 | /VRES | Output | Reset from switch | A27 | VD10 | Input/Output | |
| B28 | /LWR | Output | Active low
Lower byte WRite |
A28 | VD04 | Input/Output | |
| B29 | /UWR | Output | Active low
Upper byte WRite |
A29 | VD03 | Input/Output | |
| B30 | /M3 | Input | Active low
Force Mark 3 (Master System) mode |
A30 | VD11 | Input/Output | |
| B31 | /TIME | Output | set for r/w at/to $A13000-$A130FF | A31 | Vcc1 | Output | Positive supply voltage (+5V) |
| B32 | /CART | Input | Active low
set when cart is inserted |
A32 | GND | Ground | |