There are currently five different mainboards for the MEGA65:
- the MEGA65 R1 board
- the MEGA65 R2 board
- the MEGA65 R3 board
- the Nexys A7 100T
- the MEGAphone board
While the R1, R2 and R3 are pre-series boards that are not being sold freely (yet), the Nexys A7 is an FPGA development board by Digilent that is already available.
The MEGAphone board is the mainboard for the planned MEGAphone (duh).