From MegaDrive Development Wiki
Jump to navigation
Jump to search
| Address
|
Name
|
Read
|
Write
|
| $A10001
|
REG_VERSION
|
| Bit |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
| Def |
0 : Domestic (Japanese model)
1 : Oversea (US or European model)
|
0 : NTSC Clock (7.67Mhz)
1 : PAL Clock (7.60Mhz)
| 0 : Expansion unit connected
1 : Expansion unit not connected
| ?
| Version number |
|
?
|
| $A10003
|
REG_DATA1
|
Read the status of each pin (direction is controller by REG_CTRL1)
| Bit |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
| Def |
PD7 |
PD6 | PD5 | PD4 | PD3 | PD2 | PD1 | PD0 |
|
Set the status of each pin (ignored for input pins)
| Bit |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
| Def |
PD7 |
PD6 | PD5 | PD4 | PD3 | PD2 | PD1 | PD0 |
|
| $A10005
|
REG_DATA2
|
Status of each pin (direction is controller by REG_CTRL2)
| Bit |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
| Def |
PD7 |
PD6 | PD5 | PD4 | PD3 | PD2 | PD1 | PD0 |
|
Set the status of each pin (ignored for input pins)
| Bit |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
| Def |
PD7 |
PD6 | PD5 | PD4 | PD3 | PD2 | PD1 | PD0 |
|
| $A10007
|
REG_DATA3
|
Status of each pin (direction is controller by REG_CTRL3)
| Bit |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
| Def |
PD7 |
PD6 | PD5 | PD4 | PD3 | PD2 | PD1 | PD0 |
|
Set the status of each pin (ignored for input pins)
| Bit |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
| Def |
PD7 |
PD6 | PD5 | PD4 | PD3 | PD2 | PD1 | PD0 |
|
| $A10009
|
REG_CTRL1
|
Read the direction of the pins
| Bit |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
| Def |
INT |
PC6 | PC5 | PC4 | PC3 | PC2 | PC1 | PC0 |
|
Select the direction of the pins
| Bit |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
| Def |
INT
0 : TH-INT Prohibited
1 : TH-INT Allowed
|
PC6
0 : input
1 : output
| PC5
0 : input
1 : output
| PC4
0 : input
1 : output
| PC3
0 : input
1 : output
| PC2
0 : input
1 : output
| PC1
0 : input
1 : output
| PC0
0 : input
1 : output
|
|
| $A1000B
|
REG_CTRL2
|
Read the direction of the pins
| Bit |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
| Def |
INT |
PC6 | PC5 | PC4 | PC3 | PC2 | PC1 | PC0 |
|
Select the direction of the pin
| Bit |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
| Def |
INT
0 : TH-INT Prohibited
1 : TH-INT Allowed
|
PC6
0 : input
1 : output
| PC5
0 : input
1 : output
| PC4
0 : input
1 : output
| PC3
0 : input
1 : output
| PC2
0 : input
1 : output
| PC1
0 : input
1 : output
| PC0
0 : input
1 : output
|
|
| $A1000D
|
REG_CTRL3
|
Read the direction of the pins
| Bit |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
| Def |
INT |
PC6 | PC5 | PC4 | PC3 | PC2 | PC1 | PC0 |
|
Select the direction of the pin
| Bit |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
| Def |
INT
0 : TH-INT Prohibited
1 : TH-INT Allowed
|
PC6
0 : input
1 : output
| PC5
0 : input
1 : output
| PC4
0 : input
1 : output
| PC3
0 : input
1 : output
| PC2
0 : input
1 : output
| PC1
0 : input
1 : output
| PC0
0 : input
1 : output
|
|
| $A1000F
|
REG_TXDATA1
|
|
|
| $A10011
|
REG_RXDATA1
|
|
|
| $A10013
|
REG_S_CTRL1
|
| Bit |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
| Def |
?
|
0 : OK
1 : Rxd Error
| 0 : OK
1 : Rxd Ready
| 0 : OK
1 : TxdFull
|
|
| Bit |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
| Def |
0: 4800 bps
1: 2400 bps
2: 1200 bps
3: 300 bps
|
0 : Parallel mode
1 : Serial in
| 0 : Parallel mode
1 : Serial out
| 0 : Rxd Ready - Interrupt Prohibited
1 : Rxd Ready - Interrupt Allowed
| ? |
|
| $A10015
|
REG_TXDATA2
|
|
|
| $A10017
|
REG_RXDATA2
|
|
|
| $A10019
|
REG_S_CTRL2
|
| Bit |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
| Def |
?
|
0 : OK
1 : Rxd Error
| 0 : OK
1 : Rxd Ready
| 0 : OK
1 : TxdFull
|
|
| Bit |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
| Def |
0: 4800 bps
1: 2400 bps
2: 1200 bps
3: 300 bps
|
0 : Parallel mode
1 : Serial in
| 0 : Parallel mode
1 : Serial out
| 0 : Rxd Ready - Interrupt Prohibited
1 : Rxd Ready - Interrupt Allowed
| ? |
|
| $A1001B
|
REG_TXDATA3
|
|
|
| $A1001D
|
REG_RXDATA3
|
|
|
| $A1001F
|
REG_S_CTRL3
|
| Bit |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
| Def |
?
|
0 : OK
1 : Rxd Error
| 0 : OK
1 : Rxd Ready
| 0 : OK
1 : TxdFull
|
|
| Bit |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
| Def |
0: 4800 bps
1: 2400 bps
2: 1200 bps
3: 300 bps
|
0 : Parallel mode
1 : Serial in
| 0 : Parallel mode
1 : Serial out
| 0 : Rxd Ready - Interrupt Prohibited
1 : Rxd Ready - Interrupt Allowed
| ? |
|
| $A14000
|
REG_LOCK
|
?
|
Writing 'SEGA' (0x53454741) unlock the VDP.
Writing something else lock the VDP.
|
| $A14101
|
REG_TMSS
|
?
|
| Bit |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
| Def |
? |
0 : Disable cartridge and enable TMSS rom
1 : Disable TMSS rom and enable cartridge
|
|