Keywords: GB GAMEBOY PIC PIC16C74 Serial RS232 MAGICOM ROM DUMP Emulator

GameBoy Serial Reader

Copyright(C)1998 H.Kashima
(UNDER CONSTRUCTION) , 42076th 1998/10/28 UPDATED

  • Support BBS(japanese) Kashi's BBS
    1. Introduction
    2. This tool used RS232C serial interface. it can connect to PC-compatible and Macintosh, UNIX.

    3. Schematic Structure
    4. this is easy structure, 40pin PIC micro computer and RS232C interface, voltage regulator.

      Schematic Diagram

    5. How to make
    6. take it easy, no problem.

      PCB Art work

    7. How to use
    8. please connect cable to PC via modem-cable. and GB-Reader requires AC-Adapter(center GND, outside +12 volt)

      please access to GB-Reader with 115.2Kbps 8bit 1stopbit parity-none in any terminal software.

      GB-Reader returns prompt of "gbr>" if communication successfull. LED on the GB-Reader is linked with RESET signal on cartridge. you can remove cartridge safty in LED is black. you can use command in the command prompt.

        [ESC]		turn off cartridge power(into removable mode).
        h		display help.
        i		print information in cartridge.
        ir            refresh information from cartridge.(Ver1.0b or later)
        br, bs 	change bank register in ROM/SRAM.
          change bank register in ROM/SRAM.
            gbr> br 1e	... ROM bank change to 0x1e
            gbr> bs a		... SRAM bank change to 0x0a
        us, ds	up/download backup SRAM
            up/download backup SRAM.
          transfer time is 2 seconds at the 8KB SRAM. if push ESC key is proccess abort.
        dl		download ROM
            download ROM data. typical transfer time is about 64 seconds at 512KB
          if push down ESC key will be abort current proccess.
            gbr> dl 1000 1fff		... download by UUENCODE
                                          to 0x1fff from 0x1000
            gbr> dl			... download all
        rd	read memory
            read out memory in cartridge.
            gbr> rd a000		... read out address of 0xa000.
        wd	write memory
            write in memory in cartridge.
            gbr> wd 0 a		... write value of 0x0a to address 0x0000.
        dm	dump memory
            dump value in memory. ESC key effective.
            gbr> dm			... dump memory 128bytes from current
            gbr> dm 4000		... dump memory 128bytes from address 0x4000
            gbr> dm 4000 4fff		... dump memory to 0x4fff from 0x4000
        cs, cr     calculate checksum
            calculate checksum in current cartridge.
          please compare value from value in () printed by 'i' command. 
            gbr> cr			... calculate checksum for ROM
            gbr> cs			... calculate checksum for SRAM
            gbr> cr 4000 4fff		... calculate checksum 0x4000 - 0x4fff

    9. program for PIC
    10. reference
      • PIC16/17 Microcontroller Data Book/Microchip Technology Inc. 1996/1997
      • Errata Sheet for Rev. A PIC16C74 Silicon/Microchip Technology Inc. 1996

    11. sample data
      1. Memory Access timing in Gameboy
      2. the access is syncronized with signal of CLK 1.078MHz. RD signal is lo-level in normaly, when write operation, change to hi-level. MREQ is lo-level when access to SRAM.

      3. Sample Schematic of MBC1, MBC2 type cartridges
      4. MBC1 schematic
        MBC2 schematic

    terminal snapshots

    transfer time is 64 seconds at 512K

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