EZ80F91MCU Datasheet, PDF (323/396 Pages) Zilog, Inc. – eZ80Acclaim-TM Flash Microcontrollers

eZ80F91 MCU
Product Specification
304
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)
Bit
7
6
5
4
3
2
1
0
Reset
X
X
X
X
X
X
X
X
CPU Access
W
W
W
W
W
W
W
W
Note: X = Undefined; W = Write.
Bit
Position
[7:0]
ZDI_IS4,
ZDI_IS3,
ZDI_IS2,
ZDI_IS1,
or
ZDI_IS0
Value Description
00h–
FFh
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.
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.
PS019209-0504
PRELIMINARY
ZiLOG Debug Interface