PIC18F258 MICROCHIP [Microchip Technology], PIC18F258 Datasheet - Page 41

• Manufacturer Part Number: PIC18F258
• Description: High Performance, 28/40-Pin Enhanced FLASH Microcontrollers with CAN
• Manufacturer: MICROCHIP [Microchip Technology]

REGISTER 4-1:
FIGURE 4-3:
 2002 Microchip Technology Inc.
bit 7
bit 6
bit 5
bit 4-0 SP4:SP0: Stack Pointer Location bits
Note 1: No RAM associated with this address; always maintained ‘0’s.
TOSU
00h
STKPTR - STACK POINTER REGISTER
RETURN ADDRESS STACK AND ASSOCIATED REGISTERS
bit 7
STKFUL: Stack Full Flag bit
1 = Stack became full or overflowed
0 = Stack has not become full or overflowed
STKUNF: Stack Underflow Flag bit
1 = Stack underflow occurred
0 = Stack underflow did not occur
Unimplemented: Read as '0'
Legend:
R = Readable bit
- n = Value at POR
STKFUL
Note:
R/C-0
Bit 7 and bit 6 need to be cleared following a stack underflow or a stack overflow.
TOSH
STKUNF
1Ah
R/C-0
Top-of-Stack
TOSL
34h
Preliminary
U-0
W = Writable bit
’1’ = Bit is set
—
Return Address Stack
001A34h
000D58h
000000h
R/W-0
SP4
U = Unimplemented bit, read as ‘0’
’0’ = Bit is cleared
11111
11110
11101
00011
00010
00001
00000
R/W-0
SP3
(1)
STKPTR<4:0>
R/W-0
00010
SP2
PIC18FXX8
C = Clearable bit
R/W-0
SP1
DS41159B-page 39
R/W-0
SP0
bit 0