Z86D99 ZILOG [Zilog, Inc.], Z86D99 Datasheet - Page 66

• Manufacturer Part Number: Z86D99
• Description: Low-Voltage Micro controllers with ADC
• Manufacturer: ZILOG [Zilog, Inc.]

PS003807-1002
Bit
Bit/Field
R/W
Reset
R = Read, W = Write, X = Indeterminate
Bit
Position
76543210
Stack Pointer (SP)
The Z86D99/Z86L99 family of products is configured for an internal stack. The
size of the stack is limited only by the available memory space or general-purpose
RAM registers dedicated to this task. An 8-bit stack pointer, as described in
Table 17, is used for all stack operations.
Table 17. SP Register [Group/Bank F0h, Register F (R255)]
7
Stack Pointer
R/W
X
Bit/Field
Stack Pointer
P
6
R/W
X
R
E
L
5
R/W
X
R/W
R/W
I
M
Z86D990/Z86D991 OTP and Z86L99X ROM
4
R/W
X
Value
X
I
Low-Voltage Microcontrollers with ADC
N
A
3
R/W
X
Description
Points to the data stored on the top of
the stack; an overflow or underflow
can occur if the stack address is
incremented or decremented during
normal stack operations
R
Y
2
R/W
X
1
R/W
X
0
R/W
X
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