builderpages:plasmo:z80mb64:memmap [RetroBrew Computers Wiki]

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====== Z80MB64 and Z80SBC64 Memory, I/O map ======

===== Memory Map =====

The memory is consists of 128K of RAM in four 32-K banks:

Top 32K of RAM is the common memory. The bottom 32K can be bank selected by writing to bank select register at I/O location 0x1F as follow:

  * 0x0 is normal operation
  * 0x1 do not use
  * 0x2 is for bank 0 of CP/M-3
  * 0x3 is the reset value where the top 32K of physical memory is mapped to 0x0-0x7FFF

===== I/O Map =====

==== UART ====

A hardware receiver is implemented in CPLD with the following I/O addresses:

  * Read-only serial data receive register at 0xF9
  * Read-only serial receive status register at 0xF8 where
      * D[0] is the receive ready flag, 1 indicates data is ready, 0 indicates no data
  * Write-only bit-bang transmit register at 0xF9
      * The content of D[0] appears on the TX output pin. D[0] is high at reset. Software must "bit-bang" D[0] of transmit register to emulate the serial port transmit function.

==== Compact Flash Registers ====

Compact flash registers are 0x10 to 0x17

==== Bank Select Register ====

Bank select register is write only located at 0x1F