Yay! My 6500 returned from its sojourn to DL today and it now receives stuff on those bands with the fast wiggles, aka, 12m and 10m. Or at least it would if there were any signals to hear - the higher bands have been dead as a doornail up here in the snowy north recently.
So I'm back to developing the radio interfaces. Fortunately, all the programming I did during the time that the 6500 was on holiday seems to have worked without breaking any of the existing radio interfaces. Next up is band and mode management, closely followed by Tx/Rx control, slice management and so on.
Meanwhile, I have made a start on display processor to control processor comms. This is needed for, amongst other things, band/mode selection from the display touch screen.
In the end I decided to use the same byte-wide parallel port and protocol that I developed for the control -> display interface. It seems to work well for data to the display processor and I have sufficient spare I/O pins on both processors for separate channels for each direction. I've run out of jumper leads to connect up the second channel though, so I ordered a big bag of them on eBay yesterday. I fully expect to have bi-directional comms up and running by the end of the week.