C8051F54X_14 Datasheet, PDF (99/275 Pages) Silicon Laboratories – Mixed Signal ISP Flash MCU Family

C8051F54x
SFR Definition 12.4. SFRLAST: SFR Last
Bit
7
6
5
4
3
2
1
0
Name
SFRLAST[7:0]
Type
R/W
Reset
0
0
0
0
0
0
0
0
SFR Address = 0xA7; SFR Page = All Pages
Bit
Name
Function
7:0 SFRLAST[7:0] SFR Page Stack Bits.
This is the value that will go to the SFRNEXT register upon a return from inter-
rupt.
Write: Sets the SFR Page in the last entry of the SFR Stack. This will cause the
SFRNEXT SFR to have this SFR page value upon a return from interrupt.
Read: Returns the value of the SFR page contained in the last entry of the SFR
stack.
SFR page context is retained upon interrupts/return from interrupts in a 3 byte
SFR Page Stack: SFRPAGE is the first entry, SFRNEXT is the second, and
SFRLAST is the third entry. The SFR stack bytes may be used alter the context
in the SFR Page Stack, and will not cause the stack to “push” or “pop”. Only
interrupts and return from interrupts cause pushes and pops of the SFR Page
Stack.
Rev. 1.1
99