Hitachi HD6303 Monitor

Micro6303 Cold Boot

It lives!

The Hitachi 6303 is a variation on the Motorola MC6800/6801/6803 Motorola microprocessors and microcontrollers from the late 70’s and early 80’s.  I have an interest in reverse engineering embedded systems from that era.  Previously I have created a 6809 EPROM Monitor program called Micro09 and later a variation call Micro11 for the Motorola 68HC11.  The latter is still available on the web in a few places.  This new one, Micro6303, is basically the same beast, except for the 6303.

Micro6303 Main Menu

Micro6303 Main Menu

In all cases the idea of a Monitor is to create a development OS of sorts that can run on a minimal hardware setup.   A serial port is used for communication with the embedded system and a timer is used for single-stepping code.  The HC11 and 6303 have the timer and Serial Communications Interface on the chip, so that simplifies the hardware required to bring a system “up”.  But still quite a few components are required compared to today’s flash microcontrollers.

Micro6303 CPU Window

Micro6303 CPU Window

Anyway, without further adieu, here are some screen shots of the Micro6303 EPROM Monitor including the Cold Boot screen, the Main Menu and the CPU Window which is the facility for single-stepping and setting breakpoints. It is a work in progress and I will release binaries in the near future.

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2 Responses to Hitachi HD6303 Monitor

  1. Awesome project! Keep me posted.
    I have some old HD6303X PCB’s. These supported both Ram/Rom up to 32K, and expansion header. I had documented source to a nice monitor from Hitachi, but went through some bad times and chucked most of my hobby soft/hardware disks, parts, books etc. I still have the image in eprom, it has a built in disassembler and you can save an SREC to PC. If interested, I could send/mail one PCB/Sch to you? It’s a project of mine to update this board, ie. USB and win32 IDE GUI interface.

    • grantb4 says:

      I would definitely be interested! USB? I think it’s easiest to just go the FTDI RS232-to-USB route. It’s very solid, not sure if that’s what you had in mind though. It’s hard to find a USB controller that you can hook up to an expanded addr/data bus.

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