sgdk
sram.h File Reference

SRAM (Static RAM used for save backup) support. More...

#include "mapper.h"

Go to the source code of this file.

Defines

#define SRAM_CONTROL   MAPPER_BASE
#define SRAM_BASE   0x200001

Functions

void SRAM_enable ()
 Enable SRAM in Read Write mode.
void SRAM_enableRO ()
 Enable SRAM in Read Only mode.
void SRAM_disable ()
 Disable SRAM.
u8 SRAM_readByte (u32 offset)
 Read a byte from the SRAM.
u16 SRAM_readWord (u32 offset)
 Read a word from the SRAM.
u32 SRAM_readLong (u32 offset)
 Read a long from the SRAM.
void SRAM_writeByte (u32 offset, u8 val)
 Write a byte to the SRAM.
void SRAM_writeWord (u32 offset, u16 val)
 Write a word to the SRAM.
void SRAM_writeLong (u32 offset, u32 val)
 Write a long to the SRAM.

Detailed Description

SRAM (Static RAM used for save backup) support.

Author:
Chilly Willy & Stephane Dallongeville
Date:
08/2012

This unit provides methods to read from or write to SRAM.

Informations about SRAM (taken from Segaretro.org):
The regions specified by 0xA130F9-0xA130FF (0x200000-0x3FFFFF) can be either ROM or RAM and can be write-protected.
Here is the layout of the register as far as I know:

7 6 5 4 3 2 1 0
+-----------------------+
|??|??|??|??|??|??|WP|MD|
+-----------------------+

MD: Mode -- 0 = ROM, 1 = RAM
WP: Write protect -- 0 = writable, 1 = not writable


Function Documentation

u8 SRAM_readByte ( u32  offset)

Read a byte from the SRAM.

Parameters:
offsetOffset where we want to read.
Returns:
value.
u32 SRAM_readLong ( u32  offset)

Read a long from the SRAM.

Parameters:
offsetOffset where we want to read.
Returns:
value.
u16 SRAM_readWord ( u32  offset)

Read a word from the SRAM.

Parameters:
offsetOffset where we want to read.
Returns:
value.
void SRAM_writeByte ( u32  offset,
u8  val 
)

Write a byte to the SRAM.

Parameters:
offsetOffset where we want to write.
valValue wto write.
void SRAM_writeLong ( u32  offset,
u32  val 
)

Write a long to the SRAM.

Parameters:
offsetOffset where we want to write.
valValue wto write.
void SRAM_writeWord ( u32  offset,
u16  val 
)

Write a word to the SRAM.

Parameters:
offsetOffset where we want to write.
valValue wto write.
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