I've been slowly chipping away at the edges of a dilemma. I've been very comfortable using Dave Dunfield's MON09 monitor program for this project. It's a really nice full-featured monitor that works great, and took almost no effort to port to my hardware (i.e. integrate SCC support). I added some stuff to support the realtime clock, and the CIO, and cleaned up the hex/srec loader a bit. But, other than that, it's pretty much the code I bought from DDS, many years ago. The only drawbacks are, as I see it: 1) it's closed-source, so I can't distribute the source code or even the binary ROM code; 2) it's really a 6809 monitor, and not a 6309 monitor - it doesn't know about the extra 6309 registers, nor all of the additional 6309 opcodes.
I've avoided the temptation to fix #2, because of #1 - any effort put into the monitor can't be shared, and I'm bummed out about that. I've looked for a 6309 ROM monitor, but don't find one. I've found other 6809 monitors, all quite ancient, but they are also not open source (they predate the concept, for the most part). Ugh.
I suppose I need to get writing, then. At some point, it'll be done....
I whipped up the design for a "breakout board" to interface the 6309 SBC expansion port to my trusty Altera DE1 Cyclone II FPGA eval board. It's just a bunch of 74LVC level shifters to bring the 5V TTL down to 3.3V CMOS suitable for input into the FPGA. The idea is that I can use the DE1 to develop the VGA and sound and keyboard interface stuff, before committing to a design.I've got a low-cost Cyclone I FPGA board, also, on hand, so there's another connector to interface with that board, too. I'm not decided between Cyclone I and Cyclone II. The II is more capable and larger, but the I comes in a nice TQFP 100 package that is about the limit of what I'll hand-solder. Anyhow, this board should be helpful, I think. It's getting fabbed via OSHpark, hope to see the boards in about a week or two.
The 4.10 release of William Astle's "lwtools" assembler/linker toolchain is out. lwasm now includes the ability to write intel hex and motorola srecord output files - courtesy of yours truly. Get it at http://lwtools.projects.l-w.ca/