Options by IBM PCMCIA Serial Infrared adapter

IO space

• 0x02-0x03 Read pointer
• 0x04-0x05 Write pointer?
• 0x06 (WR only)
• 0x07 (lots of RMW)
• 0x08 CTL register
• 0x09 Two nibbles - page register (top nibble is W,bottom nibble R)
• 0x0A Scratch register [never used except in 55 AA]
• 0x0C (WR only)
• 0x10 ESCC Z85233
• 0x11 (RD ONLY) some sort of status from ESCC?
• 0x12 CTRL ==12 for UART ==10 for ESCC
• 0x13 SPEED ==3 for 228000 ==2 for 576000 ==1 for 1152000
• 0x14-0x15 Write length?
• 0x18-0x1F 16550 UART

Memory space

• 0x0000-0x0fff -> 0x0000+(R << 10)- [Ie 16K addressable in a 4K window aligned on a 1K boundary]
• 0x1000-0x1fff -> 0x4000+(W << 10)- [Ie 16K addressable in a 4K window aligned on a 1K boundary]

Log of IO and Memory accesses while running IBM diagnostics

Click on a Chip for its datasheet