Z86E30 Datasheet, PDF (33/66 Pages) Zilog, Inc. – Z8 4K OTP Microcontroller

Zilog
Z86E30/E31/E40
Z8 4K OTP Microcontroller
EPROM Protect. When in ROM Protect Mode, and exe- location 4096. In ROMless mode, the Z86E40 can address
cuting out of External Program Memory, instructions LDC, up to 64 KB of data memory. External data memory may
1 ^{LDCI, LDE, and LDEI cannot read Internal Program Mem- be included with, or separated from, the external program}
ory.
memory space. /DM, an optional I/O function that can be
programmed to appear on pin P34, is used to distinguish
When in ROM Protect Mode and executing out of Internal _{between data and program memory space (Figure 23).}
Program Memory, instructions LDC, LDCI, LDE, and LDEI _{The state of the /DM signal is controlled by the type of in-}
can read Internal Program Memory.
struction being executed. An LDC opcode references
Data Memory (/DM). In EPROM Mode, the Z86E40 can
address up to 60 KB of external data memory beginning at
PROGRAM (/DM inactive) memory, and an LDE instruc-
tion references data (/DM active Low) memory.
65535
EPROM
ROMless
External
Data
Memory
External
Data
Memory
4096
4095
0
Not Addressable
Figure 23. Data Memory Map
DS97Z8X0500
PRELIMINARY
33