Zilog Z80195 - Manual (Page 34)

Z80185/195 D EVELOPMENT K IT
U SER ' S M ANUAL
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Z ILOG
Display Version of the Monitor [V]
Entering a "V" displays the software version number
Example:
Z80185 > Version
Zilog Z8015 Monitor Version 1.2
Z80185>
Examine the MMU [X]
This command can be used to control the mapping from logical to physical memory. When you enter
an "X" at a command prompt, the monitor program reads the values in the three MMU registers (CBAR,
BBR, and CBR) and translates their values into to the “current MMU map” that it displays on the next
five lines. Next, it displays two lines describing the contents of the CBAR register, displays its
contents, and allows you to enter a new value for CBAR. After that, if the CBAR value enables/uses
the Bank area, the monitor program similarly describes BBR, displays its value, and allows you to
enter a new value for it. Finally, it describes CBR, displays its value, and allows you to enter a new
value.
If you don’t enter a new value for any of the three registers, the monitor program will return to the
command prompt after you enter <RETURN> for CBR. Otherwise it will write the new value(s) at this
point and will attempt to go back and re-display the new MMU map as before.
If you selected a combination of register values that doesn’t let the monitor program keep running,
you will not see the new MMU map. Trial and error is the easiest route to working with the MMU using
this command.
Example:
Z80185>eXamine the MMU
Current MMU Map:
Area
Logical Address Range Physical Address Range
Common 0 (Not Used)
Bank 0000-EFFF 00000-0EFFF
Common 1 F000-FFFF 0F000-0FFFF
CBAR MS 4 = Boundary between Bank and Common 1 Areas in Logical Address Space
CBAR LS 4 = Boundary between Common 0 and Bank Areas in Logical Address Space
CBAR F0 :
BBR contains adder to Bank Area Logical Address to get Physical Address
BBR 00 :
CBR contains adder to Common 1 Area Logical Address to get Physical Address
CBR 00 :
Z80185>