Sega Master System and Game Gear Hardware Reference Manual

where:

• A label is an identifier followed by a colon (:).
• A mnemonic is a reserved name for a class of instruction opcodes which have the same function.
• The operands argument1, argument2 are optional. There may be zero, one, or two arguments, depending on the instruction. When present, they are either literals, or data identifiers. The data identifiers are either reserved register names, or are assigned to data items declared elsewhere in the source file.

For example:

LOOP1:  LD HL, STARTVALUE

In this example, LOOP1 is a label, LD is the mnemonic identifier for the opcode, HL is the destination operand, and STARTVALUE is the source operand.

I.3 Revision History

I.4 Acknowledgements

[To Be Completed]

1.1 System Devices Overview

1.2 Summary of Sega Master System and Game Gear Differences

2.1 Z80 Architecture

2.2 Instruction Set Summary

3.1 BIOS ROM

3.2 RAM

[To Be Completed]

3.3 Card Slot

3.4 Cartridge Slot

1. Writing to [$DFFB..$DFFF] only affects RAM. The page frame registers are not affected.
2. Writing to a page frame register also writes to the corresponding RAM byte.
3. Reading [$DFFB..$DFFF] returns the last value written to either that byte or the corresponding page frame register.
4. Reading the page frame register returns the last value written to RAM, (including writes to RAM that occurred due to writing to the page frame register.)

In general, it is probably best to leave the RAM at $DFFB through $DFFF alone, as writing to a page frame register has the side-effect of modifying this memory.

[To Be Completed]

3.5 Expansion Slot

4.1 Peripheral Ports

4.2 Pause and Reset

4.3 Configuring the Memory System

5.1 VDP Registers

5.2 VDP Palette (CRAM)

5.3 VRAM

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

Q

R

S

T

U

V

W

X

Y

Z