// Current Memory map (best config): Minimig MiSTer
// Amiga                FPGA                Type        Usage
// $00000000-$001FFFFF  $00000000-$001FFFFF SDRAM       Chip RAM
// $00200000-$00BFFFFF  $00200000-$00BFFFFF SDRAM       Z2 Fast
// $00C00000-$00D7FFFF  $00C00000-$00D7FFFF SDRAM       Bogo
// $00D80000-$00DFFFFF  $00D80000-$00D8FFFF SDRAM       Unusued (typically top half of 1MB ROM)
// $00E00000-$00EFFFFF  $00E00000-$00EFFFFF I/O         Direct driven in tg68k.vhd
// $00F00000-$00F7FFFF  $00F00000-$00F7FFFF None        Unusued (Typically expansion ROM / cartridge)
// $00F80000-$00FFFFFF  $00F80000-$00FFFFFF SDRAM       Kickstart ROM
// $40000000-$40FFFFFF  $01000000-$01FFFFFF SDRAM       Z3 Fast RAM (16mb)
// $50000000-$5FFFFFFF  $30000000-$3FFFFFFF DDR3        Z3 Fast RAM (256mb)
// $60000000-$63FFFFFF  $2C000000-$2FFFFFFF DDR3        Retargetable Graphics (RTG) (32mb)

// MiniMig-Net - type Zorro II - Mapping probably $D9xxxx
//             - type C64-IO   - Mapping $DFxx
//             - other cores to be determined
Offset  Size    
0000    01      (READ) Status register
                7-6:    11=24/32 bit mode, I/O buffer at offset $0100
                        10=24/32 bit mode, Pointer Buffer (PB) only
                        01=16 bit mode, Pointer buffer only
                        00=8 bit mode, byte interface only
                3:  1=RXP  New packet in progress
                2:  1=ACK  Packet / byte received by HPS
                1:  1=BSY  HPS Wait to send
                0:  1=RX   New packet sent / byte sent
0001    01      (WRITE) Control register
                7-6:    11=24/32 bit mode, I/O buffer at offset $0100
                        10=24/32 bit mode, Pointer Buffer (PB) only (PB pointer is 32bit)
                        01=16 bit mode, Pointer buffer only (PB pointer is 16bit)
                        00=8 bit mode, byte interface (send 1 byte at a time to $0F)
                2:  1=ACK   Packet / byte received by CORE
                1:  1=BSY   CORE Wait to send
                0:  1=TX    New packet ready to send / byte ready
0002    02      MTU (up to 65280) | Byte interface: ignored
0004    02      MRU (up to 65280) | Byte interface: ignored
0006    02      Pointer to PB (0000=I/O buffer)
0008    02      MSB of PB (24/32 bit mode)
000A    02      (W) Size of data at pointer buffer (R) Size of payload written to PB
000F    01      Byte Interface: Byte to send/receive
0010    F0      Reserved
-- addresses above 00FF not seen by 8 bit cores or cores with 16 bit addressing space
0100    65280   HPS mapped buffer (24/32 bit address bus only) 
				Almost certainly shared with the top 64K of RTG (which won't be used)