Z86C34 Datasheet, PDF (32/70 Pages) Zilog, Inc. – CMOS Z8 MCUs WITH ASCI UART OFFER EFFICIENT, COST-EFFECTIVE DESIGN FLEXIBILITY

Z86C34/C35/C36/C44/C45/C46
CMOS Z8® MCUs with ASCI UART
FUNCTIONAL DESCRIPTION (Continued)
continuous locations. The Register Pointer addresses the
starting location of the active working register group.
R253 RP
D7 D6 D5 D4 D3 D2 D1 D0
ZiLOG
Default setting after RESET = 00000000
Expanded Register Group
Working Register Group
Figure 20. Register Pointer
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
Register Group F
F0
R15 to R0
7F
70
6F
60
5F
50
4F
40
3F
Specified Working
Register Group
30
2F
20
1F
Register Group 1
10
0F
Register Group 0
I/O Ports
00
The lower nibble
of the register
file address
provided by the
instruction points
to the specified
register
R15 to R0
R15 to R4
R3 to R0
Figure 21. Register Pointer—Detail
32
PRELIMINARY
DS007601-Z8X0499