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Fix Ramtron GB Save read/write

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- [Ramtron datasheet](https://github.com/sanni/cartreader/files/6263159/001-86207_FM18W08_256-Kbit_32_K_8_Wide_Voltage_Byt-476756.zip)
- [Write/Read capture](https://github.com/sanni/cartreader/files/6263148/write_read_gameboy_sram.zip) of the changed GB.ino from [Logic Analyzer](https://downloads.saleae.com/logic2/Logic+Setup+2.3.24-master.exe)
This commit is contained in:
sanni 2021-04-06 14:20:32 +02:00
parent fb107865f0
commit 202057879e
1 changed files with 51 additions and 31 deletions
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82
Cart_Reader/GB.ino
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@ -313,28 +313,6 @@ byte readByte_GB(word myAddress) {
return tempByte;
}
byte readByteSRAM_GB(word myAddress) {
PORTF = myAddress & 0xFF;
PORTK = (myAddress >> 8) & 0xFF;
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t");
// Switch CS(PH3) and RD(PH6) to LOW
PORTH &= ~((1 << 3) | (1 << 6));
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t");
// Read
byte tempByte = PINC;
// Switch CS(PH3) and RD(PH6) to HIGH
PORTH |= (1 << 3) | (1 << 6);
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t");
return tempByte;
}
void writeByte_GB(int myAddress, uint8_t myData) {
PORTF = myAddress & 0xFF;
PORTK = (myAddress >> 8) & 0xFF;
@ -357,6 +335,56 @@ void writeByte_GB(int myAddress, uint8_t myData) {
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t");
}
byte readByteSRAM_GB(word myAddress) {
PORTF = myAddress & 0xFF;
PORTK = (myAddress >> 8) & 0xFF;
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t");
// Pull CS(PH3) LOW
PORTH &= ~(1 << 3);
// Pull RD(PH6) LOW
PORTH &= ~(1 << 6);
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t");
// Read
byte tempByte = PINC;
// Pull CS(PH3) HIGH
PORTH |= (1 << 3);
// Pull RD(PH6) HIGH
PORTH |= (1 << 6);
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t");
return tempByte;
}
void writeByteSRAM_GB(int myAddress, uint8_t myData) {
PORTF = myAddress & 0xFF;
PORTK = (myAddress >> 8) & 0xFF;
PORTC = myData;
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t");
// Pull CS(PH3) LOW
PORTH &= ~(1 << 3);
// Pull WR(PH5) low
PORTH &= ~(1 << 5);
// Leave WE low for at least 60ns
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t");
// Pull WR(PH5) HIGH
PORTH |= (1 << 5);
// Pull CS(PH3) HIGH
PORTH |= (1 << 3);
// Leave WE high for at least 50ns
__asm__("nop\n\t""nop\n\t""nop\n\t""nop\n\t");
}
/******************************************
Game Boy functions
*****************************************/
@ -654,15 +682,7 @@ void writeSRAM_GB() {
// Write RAM
for (uint16_t sramAddress = 0xA000; sramAddress <= sramEndAddress; sramAddress++) {
// Pull CS(PH3) LOW
PORTH &= ~(1 << 3);
// Write to RAM
writeByte_GB(sramAddress, myFile.read());
asm volatile("nop");
asm volatile("nop");
asm volatile("nop");
// Pull CS(PH3) HIGH
PORTH |= (1 << 3) ;
writeByteSRAM_GB(sramAddress, myFile.read());
}
}
// Disable RAM