z86e72 ZiLOG Semiconductor, z86e72 Datasheet - Page 47

• Manufacturer Part Number: z86e72
• Description: Otp Microcontroller
• Manufacturer: ZiLOG Semiconductor

PS008704-0507
Stack
Counter/Timer Register Description
Note:
The Z86E7X external data memory or the internal register file is used for the
stack. An 8-bit stack pointer (R255) is used for the internal stack that resides in
the general-purpose registers (R4–R239). SPH is used as a general-purpose reg-
ister only when using internal stacks.
Table 13
Table 13. Expanded Register Group D
(D) 0Ch
(D) 0Bh
(D) 0Ah
FF
F0
2F
20
1F
10
0F
00
00
When SPH is used as a general-purpose register and Port 0 is
in address mode, the contents of SPH are loaded into Port 0
whenever the internal stack is accessed.
describes the expanded register group D.
The upper nibble of the register file address
provided by the register pointer specifies
the active working-register group
r
7
r
6
Specified Working
Register Group 0
Register Group 1
r
Register Group
5
Reserved
HI8
LO8
I/O Ports
r
4
Figure 24. Register Pointer
r
3
r
2
r
1
r
0
R253
The lower nibble
of the register
file address
provided by the
instruction points
to the specified
register
R15 to R0
R15 to R0
R15 to R4
R3 to R0
OTP Microcontroller
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