Z86E3016PSG Datasheet, PDF (31/348 Pages) Zilog, Inc. – Z86E3016PSG

Z8 CPU
User Manual
13
R7 R6 R5 R4 R3 R2 R1 R0
R253
(Register Pointer)
The upper nibble of the register file address,
provided by the register pointer, specifies
the active working-register group.
FF
F0
Working Register Group F
EF
80
7F
70
6F
60
5F
50
4F
40
3F
30
Specified Working Register Group
2F
20
1F
10
Working Register Group 1
0F
Working Register Group 0
The lower nibble
of the register
file address
(provided by the
instruction) points
to the specified
register.
R15 to R0
R15 to R4
00
I/O Ports
R3 to R0
*Note: The full register file is shown. Please refer to the selected device product specification for actual file size.
Figure 5. Register Pointer
Error Conditions
Registers in the Z8^® Standard Register File must be correctly used
because certain conditions produce inconsistent results and should be
avoided.
• Registers F3h and F5h–F9h are write-only registers. If an attempt is
made to read these registers, FFh is returned. Reading any write-only
register will return FFh.
UM001602-0904
Address Space