C8051F360 datasheet(93/288 Pages) SILABS

93 / 288 page

Rev. 1.0

C8051F360/1/2/3/4/5/6/7/8/9

On the execution of the RETI instruction in the ADC0 Window Comparator ISR, the value in SFRPAGE

as it did prior to the interrupts occurring. See Figure 9.8 below.

0x0F

(OSCICN)

SFRPAGE

SFRLAST

SFRNEXT

SFR Page 0x00

Automatically

popped off of the

stack on return from

interrupt

SFRNEXT

popped to

SFRPAGE

Figure 9.8. SFR Page Stack Upon Return From ADC2 Window Interrupt

Note that in the above example, all three bytes in the SFR Page Stack are accessible via the SFRPAGE,

SFRNEXT, and SFRLAST special function registers. If the stack is altered while servicing an interrupt, it is

possible to return to a different SFR Page upon interrupt exit than selected prior to the interrupt call. Direct

access to the SFR Page stack can be useful to enable real-time operating systems to control and manage

context switching between multiple tasks.

Push operations on the SFR Page Stack only occur on interrupt service, and pop operations only occur on

interrupt exit (execution on the RETI instruction). The automatic switching of the SFRPAGE and operation

of the SFR Page Stack as described above can be disabled in software by clearing the SFR Automatic

Page Enable Bit (SFRPGEN) in the SFR Page Control Register (SFR0CN). See SFR Definition 9.1.

C8051F360 Datasheet(PDF) 93 Page - Silicon Laboratories