SN8F27E64LKB datasheet(39/192 Pages) SONIX

39 / 192 page

SN8F27E60 Series

8-Bit Flash Micro-Controller with Embedded ICE and ISP

SONiX TECHNOLOGY CO., LTD

Page 39

Version 1.4

2.4 STACK OPERATION

2.4.1 OVERVIEW

The stack buffer has 8-

level. These buffers are designed to push and pop up program counter’s (PC) data when

interrupt service routine and

“CALL” instruction are executed. The STKP register is a pointer designed to point active

level in order to push or pop up data from stack buffer. The STKnH and STKnL are the stack buffers to store program

counter (PC) data.

RET /

RETI

CALL /

INTERRUPT

STKP = 7

STKP = 6

STKP = 5

STKP = 4

STACK Level

STK7H

STK6H

STK5H

STK4H

STACK Buffer

High Byte

PCH

STKP

STK7L

STK6L

STK5L

STK4L

STACK Buffer

Low Byte

PCL

STKP

STKP - 1

STKP + 1

STKP = 3

STKP = 2

STKP = 1

STKP = 0

STK3L

STK2L

STK1L

STK0L

STK3H

STK2H

STK1H

STK0H

2.4.2 STACK POINTER

The stack pointer (STKP) is a 3-bit register to store the address used to access the stack buffer, 13-bit data memory

(STKnH and STKnL) set aside for temporary storage of stack addresses. The two stack operations are writing to the

top of the stack (push) and reading from the top of stack (pop). Push operation decrements the STKP and the pop

operation increments each time. That makes the STKP always point to the top address of stack buffer and write the

last program counter value (PC) into the stack buffer.

0EFH

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

STKP

GIE

LVD24

LVD33

STKPB2

STKPB1

STKPB0

Read/Write

R/W

After reset

Bit[2:0]

STKPBn: Stack pointer (n = 0 ~ 2)

Bit 7

GIE: Global interrupt control bit.

0 = Disable.

1 = Enable. Please refer to the interrupt chapter.



Example: Stack pointer (STKP) reset, we strongly recommended to clear the stack pointers in the

beginning of the program.

MOV

A, #00000111B

B0MOV

STKP, A

SN8F27E64LKB Datasheet(PDF) 39 Page - SONiX Technology Company

SN8F27E64LKB Datasheet(HTML) 39 Page - SONiX Technology Company

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL