I've released the next version of firmware for the 8080 board.
You must change Jumper JP5 to pins 2-3 to run this firmware. The Shadow ROM Kill now happens from the I/O port.
This new version supports the Propeller Console I/O as well as the on board UART.
It will actually read from both consoles and send to both at the same time.
I have changed my approach to the firmware. Now there is only a BOOT LOADER on the EPROM, it will in turn load a BIOS.HEX file from the SD Card. This way, future bios updates can be saved to the SD Card only.
Firmware can be found here:
The Boot loader is now a little more complicated. It offers the choice to list files on the SD Card and load any Intel Hex file. The first address taken from the Intel Hex file will be the program execution address.
There is a big 4 second delay at the start of the firmware, this is to allow the Propeller board to boot up.
If a key is not pressed within a few seconds, it will proceed to load BIOS.HEX, which has also been updated to send/receive to both Propeller and on board UART.
Another option is to test RAM, this will test the upper 4K of RAM, an area that is needed by the BIOS system and otherwise not testable when using the Monitor I included.
The Bootloader occupies the bottom 4K of the ROM, but can load a hex file ANYWHERE in the 64K (because writes to memory are directed to the RAM). Well, anywhere in the lower 63K, the top 1K is needed for the SD Card Buffer and some working space.