SN8F2250B Series
USB 2.0 Full-Speed 8-Bit Micro-Controller
2.3 STACK OPERATION
2.3.1 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
PCH
PCL
STACK Buffer
High Byte
STACK Buffer
Low Byte
STACK Level
STKP = 7
STKP = 6
STKP = 5
STKP = 4
STKP = 3
STKP = 2
STKP = 1
STKP = 0
STK7H
STK6H
STK5H
STK4H
STK3H
STK2H
STK1H
STK0H
STK7L
STK6L
STK5L
STK4L
STK3L
STK2L
STK1L
STK0L
STKP + 1
STKP - 1
STKP
STKP
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