EZ80F91MCU ZILOG [Zilog, Inc.], EZ80F91MCU Datasheet - Page 323

• Manufacturer Part Number: EZ80F91MCU
• Description: eZ80Acclaim-TM Flash Microcontrollers
• Manufacturer: ZILOG [Zilog, Inc.]

PS019209-0504
Table 194. Instruction Store 4:0 Registers
(ZDI_IS4 = 21h, ZDI_IS3 = 22h, ZDI_IS2 = 23h, ZDI_IS1 = 24h, and ZDI_IS0 = 25h
in the ZDI Register Write Only Address Space)
ZDI Write Memory Register
A Write to the ZDI Write Memory register causes the eZ80F91 device to write the
8-bit data to the memory location specified by the current address in the Program
Counter. In Z80 MEMORY mode, this address is {MBASE, PC[15:0]}. In ADL
MEMORY mode, this address is PC[23:0]. The Program Counter, PC, increments
after each data Write. However, the ZDI register address does not increment auto-
matically when this register is accessed. As a result, the ZDI master is allowed to
write any number of data bytes by writing to this address one time followed by any
number of data bytes. See Table 195.
Bit
Reset
CPU Access
Note: X = Undefined; W = Write.
Bit
Position
[7:0]
ZDI_IS4,
ZDI_IS3,
ZDI_IS2,
ZDI_IS1,
or
ZDI_IS0
Value Description
00h–
FFh
W
P R E L I M I N A R Y
X
7
These registers contain the Op Codes and operands for
immediate execution by the CPU following a Write to
ZDI_IS0. The ZDI_IS0 register contains the first Op Code
of the instruction. The remaining ZDI_ISx registers
contain any additional Op Codes or operand dates
required for execution of the required instruction.
W
6
X
W
X
5
W
X
4
W
X
3
Product Specification
W
X
ZiLOG Debug Interface
2
eZ80F91 MCU
W
X
1
W
X
0
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